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ASTRONOMY

TECHNOLOGY TODAY Your Complete Guide to Astronomical Equipment

CANON EOS 60DA

A STELLAR ASTRONOMICAL AND TERRESTRIAL PERFORMER

Volume 6 • Issue 6 November-December 2012

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Contents

Cover Story: Pages 37 - 41

Shown is Canon’s 60Da DSLR, currently the only DSLR manufactured with spectrum sensitivity specifically formulated for astrophotography. Austin Grant’s cover story shares his experiences with the camera for imaging a variety of astronomical targets in combination with both a reflector and a refractor telescope, as well as for terrestrial photography. The background image of the famed Eagle Nebula (M16) was captured with the the 60Da shot through an 8-inch f/4 imaging Newtonian riding on a Hypertuned Orion Atlas. The image consists of sixty 180-second Lights at ISO and twenty Darks, Flats and Dark Flats, captured using BackyardEOS, including guiding with dithering, and processed with Images Plus 5.0 and Photoshop CS6.

In This Issue

In This Issue

12 Editor’s Note Apples to Apples

By Gary Parkerson

65 The Great Atlas of the Sky Is Biggest Really Best?

By Gary Parkerson

37 The Canon EOS 60Da Testing the 60Da on Astronomical and Terrestrial Targets

By Austin Grant

68 The Arizona Science & Astronomy Expo Attending the Inaugural 2012 Tucson ASAE

By Gary Parkerson

43 An Introduction to Astronomical Filters Part 6 Filters and Video Astronomy

By Jim Thompson 51 The Aggas 36-inch Dobsonian A Custom ATM Newt for the Apache-Sitgreaves Center for Astrophysics

By Steve Aggas 61 Driving Stepper Motors An ATM Solution

By Rick Saunders

New Products 15 STARLIGHT XPRESS LTD Oculus Camera

16 UNITRONITALIA INSTRUMENTS AND AVALON INSTRUMENTS New Avalon X-Guider 17 ASTRO-PHYSICS New Right-Angle Polar Alignment Scope

18 OPTEC Introduces FocusLynx FT for the FeatherTouch Focuser 21 JMI TELESCOPES Introduces New Accessories 22 OPTICSMART Introduces HALO Setting Circle and Leveling Base

72 Astro Tips, Tricks & Novel Solutions Adding a Fine-Focus Arm to Your Single-Speed Focuser

By Terry Alford

23 IOPTRON Introduces SkyTracker Camera Mount 25 SCOPESTUFF More New Stuff 28 STARIZONA Introduces Hyperion 16

Astronomy TECHNOLOGY TODAY

9

Contributing Writers Steven L. Aggas is an engineer and has 19 patents with 3 more pending with his name on them. He is also a black belt in Kenpo Karate. He has been into astronomy and scope building since 1981, starting with rebuilding the rickety mount of a 50-mm refractor into a smooth motion scope. He’s built award winning telescopes over the years and has been recognized at Stellafane and Astrofest.

Terry Alford has been an avid amateur astronomer for 32 years. He is currently a member of two astro clubs: Bays Mountain Astronomy Club (founding member) and Bristol Astronomy Club. For the last 11 years Terry has taught Astronomy Labs at East TN State University. His first ATM project was an equatorial pipe mount for an 8-inch reflector 32 years ago. His woodworking shop also turns out toys for grandkids.

Contents Industry News

29 GEOST DARPA Unveils SpaceView Program at ASAE 31 STARLIGHT XPRESS LTD Acquired by SX Imaging 31 SEVERAL COMPANIES ON THE MOVE Astronomics, Astronomik, and Diffraction Limited Have New Locations

Austin Grant, a high-school Chemistry and Biology teacher, is a self-described perpetual hobbyist, experienced in such areas as building computers and repairing arcade equipment.

Austin stumbled into astronomy several years ago and it soon became his primary interest.

Being a child of the digital age, it didn’t take long for him to find digital astro-imaging and he sold his last pinball machine to fund his current imaging rig. Austin shares his passion for stargazing with his students and is in the process of building a school astronomy club.

Gary Parkerson is a retired lawyer and the editor of Astronomy Technology Today. He enjoys old school visual observing as evidenced of his enjoyment of “The Great Atlas of the Sky” expressed in his review this issue. He also enjoys the opportunity to meet readers and talk shop with those in the industry as he discusses in this issue’s overview of the new ASAE event.

32 KNIGHTWARE New Version of Deep-Sky Planner 6 Rick Saunders is an amateur astronomer, inveterate tinkerer and member of the Royal Astronomical Society of Canada, London Centre. His passion is DSLR imaging and on cloudy nights he spends his time designing and building equipment to help further that passion.

Jim Thompson acquired his passion for astronomy growing up under the dark skies of Eastern Ontario (Canada) cottage country. His love of astronomy went on hiatus briefly while he completed his graduate studies in Aerospace Engineering and started a family, but Jim is now actively involved in local astronomy clubs and observing from his home in Ottawa, Canada. Jim is presently working as the manager of the Aerothermal & Performance Group at the aerospace company W.R. Davis Engineering Ltd.

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Astronomy TECHNOLOGY TODAY

35 TELESCOPE ENGINEERING COMPANY 300 F/5.6 ADL Prototype

The Supporting

CAST

The Companies And Organizations That Have Made Our Magazine Possible!

We wish to thank our advertisers without whom this magazine would not be possible.

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Optec www.optecinc.com page 47 Optic-Craft Machining www.opticcraft.com page 18 Opticsmart www.opticsmart.com page 15 Optical Supports www.opticalsupports.com page 58 Orion Telescopes and Binoculars www.oriontelescopes.com page 80 PreciseParts www.preciseparts.com page 49 ProtoStar www.fpi-protostar.com page 25 Quantum Scientific Imaging www.qsimaging.com page 76 Quarktet www.quarktet.com page 21 Rigel Systems www.rigelsys.com page 4

SkyShed Observatories www.skyshed.com page 24 Southern Stars www.southernstars.com page 17, 40 Starizona www.starizona.com page 3 Stellarvue www.stellarvue.com page 56 Tele Vue Optics www.televue.com page 8 THK Photo www.thkphoto.com page 50 Unihedron www.unihedron.com page 20 Unitronitalia Instruments www.unitronitalia.com page 52 Van Slyke Instruments www.observatory.org page 23, 37 Waite Research www.waiteresearch.com page 62

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ScopeStuff www.scopestuff.com page 23

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Eyepieces Etc. www.eyepiecesetc.com page 10

Meade Instruments www.meade.com page 79

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Woodland Hills Telescopes www.telescopes.net page 30

William Optics www.williamoptics.com page 74

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Editor’s Note

ASTRONOMY

TECHNOLOGY TODAY

Volume 6 • Issue 6 November - December 2012 Publisher Stuart Parkerson

Managing Editor Gary Parkerson

Gary Parkerson, Managing Editor

Associate Editors Austin Grant Chad E. Patterson

Art Director Lance Palmer

Staff Photographer Craig Falbaum

Web Master Richard Harris

3825 Gilbert Drive Shreveport, Louisiana 71104 info@astronomytechnologytoday.com www.astronomytechnologytoday.com Astronomy Technology Today is published bi-monthly

by Parkerson Publishing, LLC. Bulk rate postage paid at Dallas, Texas, and additional mailing offices. ©2012 Parkerson Publishing, LLC, all rights reserved. No part of this publication or its Web site may be reproduced without written permission of Parkerson Publishing, LLC. Astronomy Technology Today assumes no responsibility for the content of the articles, advertisements, or messages reproduced therein, and makes no representation or warranty whatsoever as to the completeness, accuracy, currency, or adequacy of any facts, views, opinions, statements, and recommendations it reproduces. Reference to any product, process, publication, or service of any third party by trade name, trademark, manufacturer, or otherwise does not constitute or imply the endorsement or recommendation of Astronomy Technology Today.

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Astronomy TECHNOLOGY TODAY

APPLES TO APPLES The ATT team got its first in-person, hands-on look at Canon’s 60Da at NEAIC/NEAF 2012 in April and immediately began arranging a sample for “review.” While awaiting delivery of the camera, we discussed the scope of the potential article, specifically whether it should include a comparison to other consumer, prosumer or pro Canon DSLRs that had been spectrum modified – after manufacture – specifically for astrophotography.

“We,” in that case, were associate editor Austin Grant, who would actually be using the camera and writing the article, ATT Publisher Stuart Parkerson, and me. Austin already had in hand two spectrum-modified Canons: one that he had modified himself and another that had been professionally modified by a wellknown expert in that procedure. So, comparing the 60Da shot-for-shot directly against those astrophotographydedicated Canon DSLRs would have been easy enough to do, and yet we ultimately decided to publish Austin’s impressions without such head-to-head comparisons. Here’s why.

My argument was that comparative reviews should be limited to comparison of apples to apples. Canon has brought to market an apple that has enhanced hydrogen-alpha spectrum reach right out of the box and that is still a very compe-

tent daytime terrestrial performer, again, right out of the box. Problem is, there are no other such apples on the market.

Simply put, there are no other DSLRs that can match 60Da’s range of out-ofthe-box performance. To compare it to a spectrum-modified, astro-dedicated anything else is to compare it to oranges, and what’s the point in that?

Once you start comparing apples to oranges, where do you stop? I watched Tom Simstad capture images earlier this week with a 12-inch f/3 Officina Stellare Veloce equipped with an FLI 16803 with a big 4096 by 4096, 52.1-mm diagonal sensor, and that astro-dedicated CCD camera is well beyond an orange! So, where indeed do you draw the line? For my part, I draw it strictly at apples-toapples and, for now, the 60Da is the only such dual-purpose apple in the produce market.

Austin argued briefly in favor of making the comparison and would have prevailed despite my narrow logic, but by the time the article deadline neared, he hadn’t gotten around to actually shooting the same deep-sky targets under identical imaging conditions with his two spectrum-modified Canons. Why? Because he was having too much fun imaging with the 60Da. Those two astrophotography-dedicated DSLRs had served him very well before the 60Da arrived, but

simply never returned to service after he started using the 60Da. Before long, Austin was shooting everything with the 60Da: daylight nature macros shots, birds in flight and at roost through an Orion ED80, wide-field expanses of the Milky Way, sporting events and even portraits!

Bear in mind that this is a guy who has included in his arsenal a very excellent Canon 5D Mark II. What gives? Was the 60Da better at astrophotography than Austin’s two Canon DSLRs that had been modified for use solely for that purpose or better at daylight terrestrial photography than his 5DII? No, but it was certainly better at both tasks than either the unmodified 5DII or the modified DSLRs and that made it temptingly convenient and irresistibly handy, factors that won out in more cases than not. The 60Da got more use because it could be used for both tasks. Plus, it was just so easy to use in either mode! Once Austin got used to the flip-out (Canon calls it “Vari-angle”), high-res, 3-inch, liveview monitor, he had a hard time going back to his fixed-monitor cameras.

So there you have it; no 60Da-versusspectrum-modified-DSLR shootout. What you’ll read instead is Austin’s straight-up report of his experiences with the 60Da based solely on its standalone merits. If that disappoints, blame me and blame the 60Da for being so very usable.

My only disappointment is that weather and publication schedules conspired to prevent a report of Austin’s planned use of the 60Da in movie mode for solar-system imaging, an omission ATT plans to rectify in a subsequent, supplemental article. But, if the 60Da proves as competent in that solarsystem-imaging mode as it has for both deep-sky astrophotography and daylight terrestrial photography – and other users report that it will – it will have indeed earned the status of the only DSLR that can do it all right out of the box. Meanwhile, Canon remains the only mainstream camera manufacturer to place a substantial bet on the astronomy market, and I, for one, am very glad it did.

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13

NEWPRODUCTS

STARLIGHT XPRESS LTD Introduces Oculus Camera Starlight Xpress Ltd has introduced the Oculus, a 180 degree coverage all-sky camera module, based on a 'SuperStar' camera core. It offers a high quality, low noise image, for sky conditions monitoring, meteor watches and more.

The Oculus is provided with a replaceable, scratch-resistant, polycarbonate viewing dome and a satin anodized aluminum body. The camera is USB powered, but an additional 12v anti-dew heater input is also provided.

The Starlight Xpress Oculus uses a SuperHAD CCD from Sony which offers low thermal noise and fast electronic shutter. The camera offers extremely low noise electronics as well as an f/2 180-degree fisheye lens. The SX Oculus is powered and driven by USB, however it does require a 12dc input to power the built in anti-dew heaters.

The camera was designed for long-

term exposure to the elements. Four drain holes have been included in the outer flange at the base of the dome allowing water to run off the dome and outside of the housing. Included with the

camera is a right-angle aluminum tripod bracket to secure it to whatever structure is chosen.

More information can be found at www.sxccd.com.

Astronomy TECHNOLOGY TODAY

15

NEWPRODUCTS

UNITRONITALIA INSTRUMENTS AND AVALON INSTRUMENTS New Avalon X-Guider Unitronitalia Instruments has introduced the Avalon X-Guider, a tangent mount assembly designed and built by Avalon Instruments. This new guiding device was developed for long exposure guiding during deep-sky imaging.

The Avalon X-Guider is a high precision and play-free guide scope aligning device. The Avalon X-Guider features a Vixen style dovetail mounting system for a quick-release attachment/detachment of the guide scope on the main telescope.

The X-Guider features a very compact body, innovative design and an attractive look. All metal aluminum parts are CNC machined and the screw knobs, which were specifically designed by Avalon Instruments, have a special ergonomic design and are made with a special polymer. The unit also features a very hard anti-scratch anodized surface finish with CNC engraved characters.

The Avalon X-Guider is used to easily locate guide stars during astro-imaging sessions.The ratio between the loading capacity, which is up to 5 Kg (12 lbs), and the device weight of less than 500 g (1.02 lbs), will be very useful for travelling astro imagers who must keep their equipment’s weight as low as possible.

The X-Guider mechanics are very simple, sturdy, and free from backlash in azimuth and free from flexures in typical

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Astronomy TECHNOLOGY TODAY

working situations.

The X-Guider can be operated using only one hand to turn the two thumb screws, a real plus when the user must operate in total darkness and uncomfortable positions.

Once you find the final position, you can lock the up and down movement by means of two thumb screws. The stability of the azimuth position is ensured by the pressure exerted by a very strong spring preload.

The system is free from mechanical flexures, an indispensable factor in a guiding system. The X-Guider features a particularly low-profile (only 38mm in the basic version), a detail that allows users to maintain a low center of gravity of the system, thus reducing the weight to counterbalance.

The X-Guider is equipped with an upper Vixen-style dovetail platform which is used for fastening the guide telescope. Three different accessories are available to mount the X-Guider on the

main telescope: 1) with female Vixenstyle plate for telescopes featuring a Vixen-style dovetail male bar mounted on the tube; 2) with male Vixen-style dovetail bar for telescopes mounted on double parallel female plates; and 3) with flat plate with two slotted holes for universal custom use.

All the mounting plates below the XGuider are removable and interchangeable to allow quick and effective installation on any type of platform. Special order plates can be manufactured based on customer’s design.

Pricing varies on model ordered and accessories. For more information on the Avalon X-Guider please visit their website at www.unitronitalia.com.

NEWPRODUCTS

ASTRO-PHYSICS New Right-Angle Polar Alignment Scope Astro-Physics has introduced its new Right-Angle Polar Alignment Scope (RAPAS) with LED Illuminator for A-P’s 1600GTO, Mach1GTO and all 900 and 1200 Mounts. This revolutionary design was introduced at the Northeast Imaging Conference (NEAIC) and the Northeast Astronomy Forum (NEAF) in April 2012. The reticle has since been updated for use in the Southern Hemisphere and includes finer gradations in response to suggestions from conference participants.

The advantages of the Right-Angle Polar Alignment Scope include: rightangle viewing which eliminates neck strain during polar alignment; suitability for Northern and Southern Hemispheres through 2040; precise adjustments made without rotating the Polar Alignment Scope or the Right Ascension axis; Polar alignment in light polluted areas (only Polaris needs to be seen); and batterypowered illuminator with adjustable brightness control.

Optical specs include: objective lens - 200 mm FL, 25-mm diameter; eyepiece – 22-mm wide-field orthoscopic, focusing ocular; field of view of 6 degrees; and right-angle prism diagonal.

The RAPAS was developed to attach directly to the 1600GTO mount and Astro-Physics has also designed it to retro fit into the Mach1GTO, 900 and 1200 mounts by the use of proprietary adapters for each mount type.

These adapters are push/pull adjustable for precise alignment. Once adjusted, they will retain their precision, allowing the polar alignment scope to be inserted and removed as needed while the adapter, itself, remains attached to the mount. This will also allow the polar scope to be used interchangeably with each of multiple mounts without further adjustment. The adapter’s alignment is

what allows this precision polar alignment scope to provide consistent accuracy when re-installed repeatedly with either a single mount or when used with many different mounts.

In order to obtain extreme precision, it will be necessary to perform a precise polar alignment using a traditional drift alignment (visually or with CCD camera), or by using Ray Gralak’s PEMPro/Polar Align Wizard the first time that the RAPAS is used. Once the alignment is spot-on, the push/pull adjustment screws on the adapter are used to orient Polaris into its specific location on the reticle.

The Right-Angle Polar Alignment Scope is priced at $390US and each adapter is priced at $80US. For more information visit www.astrophysics.com.

XXX TPVU IFS OTU BS T DPN

Astronomy TECHNOLOGY TODAY

17

NEWPRODUCTS

OPTEC Introduces FocusLynx FT for the FeatherTouch Focuser Optec has introduced the FocusLynx FT with QuickSync for automation of the FeatherTouch Focuser without sacrificing the FeatherTouch feel. Optec has joined forces with Starlight Instruments to provide full digital control of the FeatherTouch focuser while allowing both manual and remote operations from the same controller and motor. Dual focuser control, Wi-Fi and Ethernet network capabilities, industry standard ASCOM support, and Smartphone apps combine to provide the next generation control system for astronomical telescope focusers.

Jeff Dickerman, President of Optec, provided his thoughts on the development of the FocusLynx FT and the changes that technology has had on the astronomy products industry.

Said Dickerman, “Optec has been designing and manufacturing high-end instrumentation and devices for astronomers since 1979, including precision photometers, intelligent filter wheels, multi-port instrument selectors, camera field rotators, and temperature compensating focusers. We have watched the hobby of astronomy transition from a visual passion for the stars and wonders of the universe, into a high-tech, fast-paced and highly competitive industry filled with new electronic gadgets, high-end software products, and automation of disparate parts, products, and software seldom seen

in most hobby industries.”

He continued, “Consider that automated telescopes for the amateur were starting to appear as early as 1990. The skills required to operate a modern automated telescope may seem daunting. It is not unusual to require fluency in electronics, mechanics, networking, software, firmware, and optics, just to assemble a working telescope – regardless of whether the intent is visual use or imaging the heavens. Indeed, it seems today’s astronomer designing an observatory full of automated equipment must be as adept in all these disciplines as any systems integrator. Optec has always been on the forefront of automation though we remain essentially an “after-market” astronomy company. That is, our devices and instruments are almost always used with other excellent products – Celestron and Meade telescopes for example, or SBIG, Apogee, and QSI camera systems.”

“Optec seeks out the very best products in our industry and tries to make each just a little better. All the while, we enjoy pushing the limits of technology and automation.

Though generally known for creating devices that operate for years in remote, automated environments with little human interaction, we have recently been enjoying a renaissance of visual observing.

We find that many improvements can be

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Astronomy TECHNOLOGY TODAY

made for the visual astronomer, as well as the operator of remote automated observatories. With these thoughts in mind, our engineers looked at an excellent product competing with our venerable TCF-S Temperature Compensating Focuser – the FeatherTouch focuser manufactured by Starlight Instruments.”

He continued, “The FeatherTouch’s great claim to fame is that it is arguably the smoothest manual focuser available in astronomy today. The quintessential ‘FeatherTouch Feel’ is derived through an elegant reduction mechanism developed

by Werner Schmidt and perfected by Starlight Instruments president Jon Joseph. Werner’s design is so good that nearly every manual focuser available today has emulated the design in some

NEWPRODUCTS way. Our Optec TCF-S focuser was developed in 1999 by Gerald Persha and we feel remains the most robust and reliable digital focuser available. However, it was never really designed to be a manual device.

Indeed, the TCF-S is the ‘go-to’ focuser when you need to put a system in Antarctica with perhaps just one or two visits per year. Our focuser is robust, steady, reliable, and repeatable. While we do offer manual IN and OUT buttons with our TCF-S focuser, unattended operation remains our primary goal for the TCF-S and our new TCF-Lynx systems.”

“Because automation is our game, we looked at the problem of adding a motor to an essentially manual focuser. How do you add the ability to motorize the FeatherTouch without destroying that “smooth, buttery” feel (as my friend Jon likes to call it)? The FeatherTouch Feel is likely the reason most users choose Starlight Instruments in the first place. So the problem remains, how do you create a simple system that allows an astronomer to set up in the field and see the wonders of the universe though an eyepiece, then transform easily to a photographic setup with fully automated focusing? We’ve developed a solution to this problem, and the answer is the FocusLynx FT with QuickSync,” he concluded.

The FocusLynx FT reflects Optec’s digital automation and Starlight

Instruments FeatherTouch feel.

Combining the FocusLynx Controller Hub with a new motor housing featuring Optec’s QuickSync engagement system, the FocusLynx FT offers the best of both worlds.

Says Dickerman, “The FocusLynx Controller Hub design goals included: robust mountable case – no plastic; dual focuser capability; Ethernet and Wi-Fi connectivity; Smartphone compatibility and control; simple serial connectivity for the hobbyist; Pulse-Width Modulation control of stepper motors; higher focuser resolutions; higher torque for heavier payload capacity; and temperature compensation.”

The FocusLynx system consists of several components that can be purchased individually or as a complete package. The basic FocusLynx controller is a small, all aluminum case measuring 5 x 3 x 1-inches. On the bottom are well labeled connections for power, network, hand control, and serial cables. On top are two connectors for the focusers to be controlled. All cables are standard off-the-shelf cables with the exception of Optec’s proprietary USB/Serial cable which is included in the package.

Out-of-the-box, the FocusLynx controller will provide digital control for one focuser stepper motor. A second stepper board can be easily added to convert to

dual focuser control. Dual focuser kits are available providing everything needed to get started.

Also available in kits or as userinstalled options are a Wi-Fi add-on board for Smartphone and laptop access and an external Hand Control for users desiring push button ease and digital read-out.

The FocusLynx system was built from the ground up to be fully compatible with ASCOM focuser standards and allows multiple connections from multiple ASCOM clients. That means you can connect up through the FocusLynx Commander (included), Maxim D/L, and FocusMax simultaneously without having to disconnect and reconnect. Automation programs like ACP, CCD AutoPilot, and CCD Commander can access the dual FocusLynx focusers regardless of the physical connection.

Whether choosing serial, USB, Ethernet, or Wi-Fi connectivity, all ASCOM clients connect up easily.

Calibrating and aligning the FeatherTouch focuser is as simple as entering the actual focuser position and clicking the Sync button.

With the optional Wi-Fi module direct control of both focusers is available from a Smartphone. Free apps are available from the Google Play and the Apple Store.

While the FocusLynx system will conContinued on Page 20

Astronomy TECHNOLOGY TODAY

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NEWPRODUCTS

OPTEC (Continued from page 19) trol any unipolar stepper motor including the original TCF-S and MicroTouch motors, the PWM control circuitry really achieves peak performance with bi-polar motors. When considering a replacement for the unipolar MicroTouch motor, Optec engineers considered the most important needs for digital focusing today.

Among the most significant: high resolution using smaller step sizes; more power for heavier camera payloads; and temperature compensation for fewer re-focus adjustments.

Says Dickerman, “With new information revealing the Critical Focus Zone is smaller than originally thought, higher resolution and smaller step sizes are essential. The FocusLynx FT offers the highest resolution currently available with 1-micron steps. As camera and instrument packages continue to become heavier, the focuser must be able to move these

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Astronomy TECHNOLOGY TODAY

heavier loads without slipping. Lab tests with a FeatherTouch 2.7-inch focuser pushed 35-lbs. vertically without hesitation. FocusLynx FT incorporates a temperature sensor at the telescope, where it belongs, and produces a much more reliable temperature compensation algorithm for accurate automatic temperature adjustments. An easy-to-use Temperature Compensation Wizard makes determining the system TC (temperature coefficient) simple without loss of imaging time.”

He continued, “What really makes the FT motor assembly unique is QuickSync - a smooth clutch mechanism that allows simple manual engagement of the focus motor. Rotate the QuickSync motor housing forward to engage the motor and control the focuser electronically, then rotate the motor housing backward to disengage the motor and resume

manual fine focus.”

The FT QuickSync motor assemblies are available in three sizes packaged with the FocusLynx controller, power supply, and all required cables. The FT QuickSync motor assembly is also available separately as an add-on for a second focuser package.

FocusLynx FT is available in three models to match the various FeatherTouch focuser sizes: FocusLynx FT20 which fits the classic 2-inch FeatherTouch focusers; FocusLynx FT30 which fits the 2.5-inch, 2.7-inch, and 3-inch FeatherTouch focusers; and FocusLynx FT40 which fits the large 3.5-inch and 4-inch FeatherTouch focusers.

The FT20, FT30, and FT40 packages include the FocusLynx controller, power supply, cables, software, and FT motor housing. Offering a complete solution right out of the box, hardware and software installation takes less than 10 minutes.

For owners of existing MicroTouch motors, Optec offers a special low-cost cable option to control the unipolar motor of the original Starlight Instruments MicroTouch. While users won’t enjoy the higher resolution, higher torque, and QuickSync convenience the FocusLynx FT offers, the FocusLynx controller can drive the MicroTouch unipolar motor well with no other loss of performance.

Resolution remains at 6.5 microns per step for FeatherTouch classic Crayford focusers and 0.26 microns per step for SCT Micro focusers. A simple MicroTouch motor control cable can be made from any Ethernet Cat5 cable. Optec offers complete packages which include the FocusLynx hub and this motor cable, or a full temperature probe kit to allow temperature compensation with the FocusLynx controller and MicroTouch motor.

Pricing of the FocusLynx FT varies based on configuration. More information is available at ww.optecinc.com.

NEWPRODUCTS

JMI TELESCOPES Introduces New Accessories Sometimes the simplest accessories are some of our favorites. JMI has a long history helping amateur astronomers better accessorize their equipment.

The new Counterweight Caddy for German equatorial counterweights is one of those simple solutions that makes it much easier to transport counterweights.

It accommodates from one to three counterweights (up to 4-3/4-inch diameter and 6-1/4-inch total length) included with most German Equatorial mounts by containing them in a steel support with a carrying handle.

The Caddy will accommodate several different model mount counterweights including those from iOptron, Meade, and Orion. It is priced at $49.95US. JMI has also introduced a Rechargeable Power PAC for Wheeley Bars. The Power PAC (Power And Convenience) attaches easily to any Universal-style Wheeley Bars and the slotted mounting tabs make it easy to attach to other equipment.

The Power PAC has two versions, a 7.0 amp-hour unit (one 12vDC battery) and a 21.0 amp-hour unit (three 12vDC batteries in parallel). Output options include a standard 12vDC cigarette

lighter power jack and a barrel 12vDC power jack. An automatic reset circuit breaker is included. The batteries are charged by plugging the included 110vAC/60Hz to 12vDC wall adapter into the barrel jack.

For more information visit www.jimsmobile.com.

Astronomy TECHNOLOGY TODAY

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NEWPRODUCTS

OPTICSMART Introduces HALO Setting Circle and Leveling Base Opticsmart has introduced the HALO combination setting circle and leveling base that is used to set the Azimuth coordinates of a Dobsonian Telescope.

HALO's are machined from Extira, a proprietary composite wood product that is strong, light, and virtually weatherproof. They are capable of supporting several times the weight of the Dobsonian telescopes they are designed to support.

Intended to accommodate Opticsmart’s line of Apertura Dobsonians, the HALO is offered in several sizes that can also accommodate other telescopes includ-

ing Orion, Sky-Watcher, and Zhumell Dobsonians.

If your telescope base is something other than an Apertura, before ordering you should measure the diameter of your Dobsonian's groundboard (including the rubber bumper-edge) to ensure that your base matches other standard bases by your telescope's manufacturer and contact Opticsmart for confirmation of fit.

Also available is a Digital Angle Gauge which is sold separately. The HALO is priced from $159.95US. For more information visit www.opticsmart.com.

Introducing the 1600GTO German Equatorial Mount We proudly introduce the new 1600GTO German Equatorial Mount, which features optional Absolute Encoders available for both R.A. and Dec. - the pinnacle of precision. The Absolute Encoders provide completely error-free tracking, software readable absolute position, homing and customizable limit functions.

“Thirty plus years of mount building expertise has been employed to engineer and build our new 1600GTO mount into the most robust, high precision mount in its class. We have enhanced its design and utility by incorporating additional optional features like absolute encoders, sophisticated control systems and a new precision polar scope to exceed the needs of even the most demanding astro-imager or visual enthusiast.” Roland Christen, President & Owner of Astro-Physics, Inc. With a capacity of 220 lbs (100 kg), the 1600GTO is ideal for refractors up to 250mm, or 18-20” Cassegrains, Ritchey-Chretiens and CDKs. It has the ability to image past the meridian for up to six hours. The 1600GTO is transportable with through-the-mount cabling and keypad and/or computer control. Every part is hand finished and inspected. All assembly is done by hand to guarantee the quality and reliability we at Astro-Physics demand and that our customers have come to expect.

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Astronomy TECHNOLOGY TODAY

NEWPRODUCTS

IOPTRON Introduces SkyTracker Camera Mount iOptron has introduced the new iOptron SkyTracker camera mount for astrophotography. This portable mount makes it easy to take long exposures of the night sky without streaking or star trailing.

The SkyTracker is simple to set up. Just attach the unit to any standard camera tripod. Then slide and lock your digital camera into the saddle.

Align SkyTracker to Polaris, the North Star, using the included dark field illuminated polar scope. Then turn on the motor and it keeps your camera tracking at the same speed the earth rotates. The DC servo motor keeps the

camera in motion to avoid star trails and allows you to take long exposures for beautiful images of the night sky.

SkyTracker runs on 4AA batteries for portability at any location.

Features include: accepts cameras weighing up to 6.6 lb (3 kg); auto-tracking for long-term exposures’ up to 24 hours of operation on 4AA batteries; included padded carry bag; and optional ball heads available separately.

It is priced at $399US and is being offered for a limited time promotional price of $348US. For more information visit www.ioptron.com.

Telescope Accessories & Hardware FEATURING ITEMS FROM:

TeleGizmos Covers - Astrozap Dew Shields Dew-Not Dew Heaters - Peterson Engineering Antares - Telrad - Rigel Systems - Sky Spot Starbound Chairs - Smart Astronomy David Chandler - Lightwedge - Baader ScopeStuff Piggyback & Balance Kits Rings, Rails, Dovetails, Cables, ATM, Eyepieces, Filters, Diagonals, Adapters Green Lasers - And MUCH more!

www.scopestuff.com 512-259-9778

Astronomy TECHNOLOGY TODAY

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NEWPRODUCTS

SCOPESTUFF More New Stuff ScopeStuff ’s new TV2S Mount Adapter lets you mount your Orion, Vixen, Skywatcher, and other scopes on mounts that have the 3-inch wide Losmandy or Tele Vue head. The adapter features anodized aluminum components, large clamp knobs with round tip brass bolts, and stainless steel hardware.

It weighs 1.9 lbs and is 9.125-inches in overall length. It solidly holds 1.7-inch base width dovetails as short as 6.5-inches. It is priced at $109US.

They are offered in three sizes including: 1) #EQBF - shaft with 8-mm threads fits LXD55/75 mounts; 2) #EQBE - shaft with 6-mm threads fits CG5, EQ3 type mounts and CGEM with 6mm hole; and #EQBG - shaft with 12-mm threads fits CGEM with 12-mm hole. Each is priced at $34US.

tional clearance. Available with 3-inch, 3.5-inch or 4-inch cradle rings each is priced at $99US.

Of course there is much more stuff to see at www.scopestuff.com.

Their new 6-inch Counterweight Shaft Extensions for GEM Mounts are stainless steel extensions that are 6-inches long and weigh 3/4 lb. They feature a stainless steel male threaded stud on one end and tapped hole on the other end.

Your toe-saver cap screws into the end.

Mount and cap screw not included.

ScopeStuff ’s Finder Mounting Rail and Rings for Orion, Synta, and Vixen type finder shoes offer a versatile way to mount finders or small scopes on a finder mounting shoe. The mounting foot fits these type shoes with a 1.3-inch wide dovetail slot. The cradle rings have threepoint flat-tip nylon thumbscrews and can be secured anywhere on the 8-inch long rail. For added stability a thumbscrew can support the front of the rail.

Supplied spacer washers can be added between the rail and the foot for addi-

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Astronomy TECHNOLOGY TODAY

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NEWPRODUCTS

STARIZONA Introduces New Hyperion Telescopes Building upon the success of its 12.5inch f/8 Hyperion astrograph, Starizona has developed a larger 16-inch f/7.3 version of that platform designed to deliver an exceptionally large, high-quality field of view. With a 70-mm diffraction-limited image circle, this new Hyperion telescope produces ideal star images over a field large enough to accommodate even the biggest CCD sensors. The Hyperion was engineered to deliver exquisite optical performance and high-quality mechanical design at a very competitive price.

Standard features include a high-precision instrument rotator, integrated telescopecontrol panel, and wireless computer control.

The instrument rotator is integrated into the back of the telescope and uses a custom 6inch brass worm gear and unique stainlesssteel bearing system, allowing for a precise and robust design. The telescope control panel, built into the back plate of the telescope, fea-

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Astronomy TECHNOLOGY TODAY

tures a digital readout display and controls the instrument rotator, cooling fans, dew heaters, and two MicroTouch autofocusers (one for the Hyperion 16 and one for an optional piggyback instrument). All telescope electronic functions are controlled from the user’s computer via a tiny wireless USB box, eliminating the tangle of cables normally associated with running imaging accessories. All features are ASCOM compatible, allowing for automation with popular imaging control software.

Features and Specifications Flat-field, Harmer-Wynne optical design; 70-mm (1.4°) diffraction-limited image circle; no chromatic aberration over 350 nm-to-1100 nm range; low thermal expansion carbon-fiber truss poles; 18-point flotation mirror cell; Starlight Instruments 3.5-inch Feather Touch focuser; MicroTouch temperature-compensating autofocuser; high-

precision instrument rotator; integrated telescope control panel with automatic and manual control of telescope electronics; digital readout display; wireless computer interface; ASCOM-compliant electronic features; CNC machined 6061 aluminum construction; heavy-duty Losmandy-style dovetails (top and bottom); two rear-cell cooling fans for rapid thermal stabilization.

Aperture: 16 inches (406 mm); Focal Ratio: f/7.3; Focal Length: 2960mm; Secondary Mirror Diameter: 6.9 inches; Overall Length: 41 inches (48 inches with focuser); Overall Height (between dovetails): 20.4 inches; Overall Width: 19.7 inches; Total Weight: 98 lbs.The introductory price of the Hyperion 16 is $20,000US.

INDUSTRYNEWS On display at the Starizona exhibit at ASAE 2012 was a new truss-tube configuration of its popular 12.5-inch Hyperion astrograph.

The truss-tube option offers the same optical and mechanical advantages of the solid carbon-fiber version, but in a format that also offers inherent air-circulation advantages.

Standard features still include a flat-field, Harmer-Wynne optical design that produces a 70-mm (1.6-degree) diffraction-limited image circle and an RMS spot radius of less than 6 microns over an 84-mm (1.9-degree) field. Also standard are a Starlight Instruments 3.5-inch Feather Touch Focuser with MicroTouch temperature-compensating autofocus system, a builtin , high-precision instrument rotator, an integrated control panel with digital-readout display for automatic and manual control of the telescope electronic systems, a wireless computer interface, all ASCOM-compliant electronics, primary and secondary dew heaters and rear-mounted cooling fans.

Additional information, including introductory pricing, is soon to be posted at www.starizona.com.

GEOST, INC. DARPA Unveils SpaceView Program at ASAE NASA estimates more than 500,000 pieces of hazardous space debris orbit the earth, threatening satellites that support peacekeeping and combat missions. These objects include spent rocket stages, defunct satellites and fragments from other spacecraft that are the result of erosion, explosion and collision. A collision between one of these small pieces of debris and a satellite could release more than 20,000 times the energy of a head-on automobile collision at 65 mph.

To help address the threat, DARPA created SpaceView, a space debris tracking project that provides amateur astronomers with the means to make a difference.

Amateur astronomers had their first opportunity to sign up in person for the program at the Arizona Science and Astronomy Expo in Tucson, November 10-11, 2012.

The vision behind the SpaceView program is to provide more diverse data to the Space Surveillance Network (SSN), a U.S. Air Force program charged with cataloging and observing space objects to identify potential near-term collisions. SpaceView hopes to achieve that goal by engaging U.S. amateur astronomers by purchasing remote access to an already in-use telescope or by providing a telescope to selected astronomers. When a telescope that is provided by the program is not in use by the SpaceView program, DARPA will provide its use for astronomy and

astrophotography.

“There is an untold amount of potential in the amateur astronomy community that we hope to use to broaden our situational awareness in space,” said Lt Col Travis Blake, USAF, DARPA program manager. “SpaceView should provide more diverse data from different geographic locations to ensure we have a robust understanding of the current and future state of our space assets.”

Interested astronomers may learn more about the program and sign up at www.spaceviewnetwork.com. Participants will be selected based on geographic location and access to a permanent site for a telescope, among other criteria. In the first phase of the program, the program team will evaluate options for commercial offthe-shelf telescopes to determine which capabilities are best suited to the task.

SpaceView is part of a larger DARPA program, OrbitOutlook, which seeks to improve the accuracy and timeliness of the SSN, a worldwide network of 29 space surveillance sensors (radar and optical telescopes, both military and civilian) that are focused on observing space objects.

GEOST, Inc., a research and development firm in Tucson, Arizona, has been contracted to develop the SpaceView network. A similar effort, StellarView, will focus on engaging the academic community and is scheduled to kick-off in 2013.

A big Dob on an Equatorial Platform is the ultimate observing machine. The Platform gives you precision tracking, whether you are observing with a high-power eyepiece, imaging with a CCD camera,or doing live video viewing with a MallinCam. Just check out this image of NGC3628 taken by Glenn Schaeffer with a 20-inch Dob on one of our Aluminum Platforms!

Visit our website for details about our wood and metal Equatorial Platforms, as well as our line of large-aperture alt/az SpicaEyes Telescopes. You can also call or email for a free color brochure.

274-9113 • tomosy@nccn.net EQUATORIAL PLATFORMS (530) www.equatorialplatforms.com Astronomy TECHNOLOGY TODAY

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Tired of fighting to get the best prices AND the best customer service?

INDUSTRYNEWS

STARLIGHT XPRESS LTD Acquired by SX Imaging Berkshire, UK’s SX Imaging has announced the completion of its acquisition of Starlight Xpress Ltd, a designer and manufacturer cooled CCD cameras for astronomy, life science and industrial applications.

The transaction was finalized in July 2012. Under the terms of agreement, Starlight Xpress Ltd will become a wholly

owned subsidiary of SX Imaging Ltd which is majority owned by Terry Platt and Michael Hattey, two of the founding members of Starlight Xpress Ltd. Terry Platt, Technical Director of SX Imaging Ltd. said, “The acquisition of 100% control of Starlight Xpress Ltd will allow us to continue to advance the excellent growth that we have seen over the previous

years and allow us more freedom to explore and develop new ideas, increasing our portfolio of world class imaging products.”

Established in 1991, Starlight Xpress Ltd will continue trading as its own entity with a seamless transition throughout the acquisition process.

For more information please visit their website at www.sxccd.com.

SEVERAL COMPANIES ON THE MOVE Astronomics, Astronomik, and Diffraction Limited Have New Locations Astronomics celebrated the grand opening of its new showroom and location in Norman, Oklahoma on Saturday, September 29. The new showroom features over 4,000 square feet with over 120 telescopes on display (Image 1).

While they have been open in the new location the past two months prior to the event, the official grand opening was an opportunity for vendors, customers and employees to get together to check out the new store.

The event featured numerous giveaways including a set of Ethos eyepieces from Tele Vue, a Celestron NexStar 8SE telescope, a Meade LS-6 Advanced ComaFree LightSwitch telescope, and more.

Factory reps and well-known astrophotographers were on hand to demo products and answer questions. For more information about Astronomics’ new facility, please visit www.astronomics.com.

Canadian based Diffraction Limited has announced that it has moved to new offices in Ottawa, Ontario. Diffraction Limited was founded in 1993 by President/CEO Douglas B. George to develop high quality software and hardware tools for scientific imaging applications.

Their products include imaging software for astronomical, biomedical,

industrial, and general laboratory use.

They also produce OEM hardware and software, including dome automation systems, control and data reduction systems for genome scanners, and imaging software for electron microscopes.

The company’s astronomy product offerings include MaxIm DL astronomy imaging software, MaxDome II observatory dome control systems, Boltwood Cloud Sensors systems, MaxPoint telescope mount modeling software, and Quick Fringe quantitative optical wavefront analysis. For more information visit www.cyanogen.com.

Gerd Newman and the crew at Astronomik have moved into its new headquarters in Hamburg, Germany.

Moving is never fun and Gerd sent us this pic (Image 2) of a piece of equipment being lifted with a crane to be placed in the facility, obviously the move was a lot of work!

For more than 10 years Astronomik has offered a full line of visual and photographic filters for the astronomical community. The company developed the innovative Clip-Filter system for Canon EOS cameras that clips in above the mirror without affecting the normal functions of the camera. For more information please visit www.astronomik.com.

Image 1

Image 2 Astronomy TECHNOLOGY TODAY

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INDUSTRYNEWS

KNIGHTWARE New Version of Deep-Sky Planner 6 Knightware has announced the release of a new version of its Deep-Sky Planner planning and logging software. Deep-Sky Planner 6 provides a complete set of planning features, upto-date and comprehensive database of visual and imaging targets, extensive logging facilities and easy to use interface. This complete package allows users to plan imaging and observing in advance, and provides real-time telescope control and observing information while working at the telescope.

The Deep-Sky Planner 6 database has been expanded to 1.25 million objects and is extensively cross referenced. The database contains professional, peer-reviewed data taken from the most up-to-date catalogs, including the Revised NGC/IC by Dr. Wolfgang Steinicke.

The database also includes data for individual members of Arp Peculiar Galaxy groups that have never been published before (see image).

The observing log is fully integrated with planning features and provides extensive capability, including support for attaching video and audio clips to observations. Observations can be shared with any other software that supports OpenAstronomyLog 2.x standard format.

Reports include detailed data that help determine when and what to observe, such as real-time altitude/azimuth, surface brightness and morphology for appropriate objects and equipment metrics (on the Equipment Bar).

Data filters and sorting options are applied dynamically as an observing plan runs in realtime, allowing access to updated information

throughout an observing session. New features have been added that assist double and variable star observers. These include high precision ephemerides for well-studied visual binary stars, and light extrema predictions for variables.

Knightware’s Smart Chart Inter-operation allows users to select a celestial object in a report and switch instantly to a planetarium view of the object. The view may be scaled to a field of view defined by the user, a selected optical system or the object being observed. DeepSky Planner 6 offers flexibility by supporting several commercial and free planetarium programs including TheSkyX, TheSky6, Starry Night, Redshift and Cartes du Ciel.

Deep-Sky Planner 6’s well-designed user

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Next Generation Roll off Roof and Dome Controllers are now available.

Now is the time to automate your astrophotography!

CHECK OUT OUR WEBSITE FOR ALL THE DETAILS! www.fostersystems.com

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Astronomy TECHNOLOGY TODAY

interface complies with Windows Software Logo guidelines, which means the software behaves like a normal Windows product and users have a smaller learning curve. It is designed for the User Account Control security scheme in Windows 8, 7 and Vista, thereby eliminating the security problems many products can have with newer versions of Windows.

Deep-Sky Planner 6 provides import and export functions in several formats for the observing log, observing plans and equipment lists. Observing plans can be imported from other software, and they can be exported directly to Argo Navis, Sky Commander and SkySafari (on iOS, Android and Mac OS).

Users can browse the online Plan Library in the Licensed User’s Community for hundreds of pre-built observing plans that accompany many popular books, magazines and online articles. Plans in the Library can be viewed in the field from any internet-connected mobile device with a web browser.

Deep-Sky Planner 6 operates on Windows 8, 7, Vista and XP. It includes thorough online and printable documentation, online product support and online product updates. Deep-Sky Planner 6 is available by digital delivery ($72) and on CD ($80.95) directly from Knightware. For full product description please see www.knightware.biz.

INDUSTRYNEWS

TELESCOPE ENGINEERING COMPANY Exhibits 300 F/5.6 ADL Among the new telescope prototypes displayed at ASAE 2012 was TEC’s latest project, a 300-mm f/5.6 (1680-mm focal length) dubbed “ADL” for Astrograph Diffraction Limited. The five-element design includes a three-lens field corrector and illuminates a field diameter of 52 mm, covering a 36- by

36-mm sensor.

The mirror substrates are composed of quartz or zero-expansion Astrositall, and the primary mirror is cooled by four Papst low-vibration fans. The OTA is constructed from aluminum alloy and titanium tubes, and is fully thermocompensated.

Overall weight of the new scope is approximately 36 pounds (16 kilograms) and its overall length is 29 inches (735 mm). The focuser is of helical design and features a travel of 10 mm.

Optional accessories include a Kendrick Astro Instruments dew controller with secondary-mirror heating, an FLI Atlas focuser and a 9-inch TEC dovetail.

Introductory pricing for the new astrograph is targeted at $12,600US.

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Astronomy TECHNOLOGY TODAY

Testing the 60Da on Astro and Terrestrial Targets

The Canon EOS 60Da

By Austin Grant

Editor’s Note: The proof of the following evaluation of Canon’s 60Da is ultimately in the pudding of the photos that accompany this article, and, as always, the photos display with far greater fidelity in their online digital form than on these newsprint pages. Fortunately, your subscription includes online access to this entire issue of ATT. In the world of astrophotography, many an endeavor begins with a DSLR. This type of camera comes highly recommended, as it’s quite versatile and readily available. Realizing this, in 2005 Canon was the first company to release an astrophotography-specific DSLR, the 20Da. When they announced a successor, the 60Da, I knew I had to get my hands on one. I saw my first 60Da at NEAIC and NEAF 2012, and was immediately impressed with it, so it was only a matter of time before I had one to use under the night sky.

The manual controls of a DSLR make it

easy to immediately take wide-field astrophotos, and it only takes a couple of inexpensive accessories to attach these cameras to a telescope for prime-focus imaging. Where these cameras really shine is in the fact that, unlike dedicated astro-cameras, they are also excellent for taking conventional photographs.

The 60Da is essentially a factory-modified version of the 60D, a refined “prosumer” camera with a robust feature set wrapped into a slick package.

What’s Included?

In the box, there are a few more accessories than you’d get with a standard DSLR purchase. Of course, you’ll get the camera body, a battery and charger. Then there are the common accessories, including software, a neck strap, USB and AV cables, and instruction manuals. What’s different about this package is the inclusion of an AC adapter and a remote-controller adapter.

There are two big disadvantages to using batteries for astrophotography: They don’t last forever (especially in cold weather) and they generate heat. The minor annoyance of changing batteries isn’t a big deal, but that extra heat causes extra thermal noise. The cooler the camera is, the less noise the images will have. This is where the AC adapter comes in. Not only do you get endless power, you reduce that extra heat buildup.

The other accessory, the RA-E3 remotecontroller adapter, is included so you can use Canon’s TC-80N3 Timer Remote Controller with the 60Da. Though not included, the TC-80N3 is an accessory that’s easy to recommend. It allows you to set exposure durations up to 99-hours, control the intervals, and set up how many images to take, all without having to connect to a computer.

The camera is built around an 18.0 Megapixel CMOS sensor, with 4.3-micron pixels. This provides excellent sampling for Astronomy TECHNOLOGY TODAY

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THE CANON EOS 60DA

Image 1 - M16, The Eagle Nebula: 60 times 180-second, Lights at ISO 1000. 20 Darks, Flats and Dark Flats. Captured with BackyardEOS, including guiding with dithering, using a Canon 60Da shot through an 8-inch f/4 imaging Newt riding on a Hypertuned Orion Atlas. Processed with Images Plus 5.0 Beta and Photoshop CS6.

short- to medium-focal-length telescopes as well as telephoto lenses. The DIGIC 4 proces-

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Astronomy TECHNOLOGY TODAY

sor makes shooting snappy, with a continuous shooting speed of 5.3 shots/second and

maximum bursts of 58 or 16 shots, in JPEG or RAW respectively. Where the processor really shines is when you choose to shoot photos in JPEG format. Autofocus is precise, with nine cross-type points, and the camera has 63 metering zones for accurate exposures.

All these features would be great in any housing, but the body of the 60Da is especially nice. I’ve got a 5D Mark II and a 40D, and, in my opinion, the contours and ergonomics of this camera eclipse either of those. The grip has been redesigned, and it just feels better in my hand.

A controversial move has been the change from a Magnesium-alloy body to a polycarbonate composite, but I found it to be lighter and easier to use while still being plenty durable.

My favorite feature is the flip-out 3.0inch Vari-angle LCD. The high-resolution display coupled with 5X and 10X zoom made finding sharp focus a breeze and was especially useful when shooting video. I also found it to be a game changer for focusing astrophotos, when not using a computer, and for birding,

THE CANON EOS 60DA where it’s often tough to get right behind the camera.

Astrophotography I glossed over it earlier, but the main difference between this camera and a standard 60D is the increased sensitivity to hydrogenalpha light. The human eye is not very sensitive to this light at the red end of the visible spectrum, so camera manufacturers filter incoming light to help the camera recreate what we see. This is great for terrestrial photographs, but can often be a hindrance to obtaining quality astrophotos. Many astrophoto targets are hydrogen-alpha emission nebulae, so that filter plays a huge part in reducing what the camera picks up. Enter the 60Da, where Canon has installed a much less aggressive Infrared-cut filter, resulting in the camera collecting three times more data in that hydrogen-alpha zone than a stock 60D. While it’s not as sensitive as having no filter, it’s more than adequate for capturing impressive shots of the heavens. It also filters enough of that extra data that, in combination with the Auto White Balance algorithm for this camera, or a Custom White Balance, it’s easy to get very usable daytime shots. Any noticeable color cast is easily corrected in post processing.

When I set up to test this camera, I decided to first use the very handy EOS Utility software that comes bundled. Once I’d gone through the settings and satisfied that curiosity, I transitioned to BackyardEOS. If you do any DSLR astro-imaging, it’s worth your time to check it out, as it’s low cost and simple to operate, but crammed with fantastic features that will help you image more effectively.

Once everything was ready to roll, I spent several hours hopping around the sky taking test shots. For framing, I usually shoot at the incredibly high ISO (in the astronomy world, anyway) of 6400. Of course, it was noisy, but not nearly as much as I’d expected.

Once I had tested a few targets, I decided to spend some time imaging M16, The Eagle Nebula. I selected this target because it’s primarily composed of hydrogen-alpha data, and it certainly didn’t disappoint. I’ve shot it

Image 2 - M33, The Triangulum Galaxy. 54 times 300-second Lights at ISO 800. 9 Darks, Flats and Dark Flats. Captured with a Canon 60Da through an 8-inch f/4 imaging Newt riding on a Hypertuned Orion Atlas. Processed with Images Plus and Photoshop CS6.

Astronomy TECHNOLOGY TODAY

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THE CANON EOS 60DA

Image 3 - M31, The Andromeda Galaxy. 60 times 300-second Lights at ISO 800. 10 Darks, Flats and Dark Flats. Shot with a Canon 60Da through an Orion ED80 (with reducer/flattener), riding on a Hypertuned Orion Atlas. Processed in Images Plus and Photoshop CS6.

with a couple different cameras before, and the results this time were superior to all my prior efforts. Finding adequate hydrogen-

alpha in M16 is like looking for water at Niagara Falls.

My next target would put up slightly

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Astronomy TECHNOLOGY TODAY

more of a challenge: M33, The Triangulum Galaxy. I collected several hours of data on it, and was surprised at how strong the Halpha data was. Again, this was no challenge.

Beautiful, detailed pockets of H-alpha were everywhere.

Finally, I decided to move to M31, The Andromeda Galaxy. This one was tough! It’s often one of the first astrophotos that people take, but I find it very difficult to process. My initial data showed lots of muddy color in the core, but no significant H-alpha data and none of the characteristic blue halo. After another night of imaging, with data totaling 5hours, I was able to make the colors pop. The data revealed a rich outer layer of blue and white stars that was peppered with zones of H-alpha gas.

I typically image with a reflector, but wanted to also get some shots using a refractor with this camera. One of the possible concerns with reducing IR filtration is that stars can get bloated. I didn’t expect that to be the case, and saw no indication of it. Depending on what type of camera or filtration you have, because of refraction, it’s often necessary to add a Luminance or IR filter to the equation.

Again, it wasn’t an issue with the 60Da, and the stars were nice and tight.

One thing I didn’t get to try before the deadline for this article was shooting in movie mode. This camera has a very good movie mode, and one setting in particular is useful for solar system imaging. If you change the settings to the 640x480 Movie Crop mode, you end up with a 1:1 pixel resolution video at 60 frames per second. This is an excellent setting for solar, lunar and planetary imaging, as there is no scaling of the image. You’re left with lots of true detail, and it’s captured very quickly. There are lots of great shots floating around taken with a 60Da in Movie Crop mode, and I hope to test it soon myself now that Jupiter is back and to report those experiences in a supplement to this article.

All in all, I found the 60Da’s performance for astrophotography to be, well, stellar!

The camera picked up more than enough Halpha data for successful deep-sky imaging. At the ISOs I used, ranging from 800-1600, the

THE CANON EOS 60DA RAW files displayed fairly low noise while retaining plenty of usable dynamic range. The next task was to see how this thing performed during daylight.

Terrestrial Photography For daylight shooting, I took the camera on several outings and photographed a variety of targets under a range of shooting conditions. I started by using it for some sideline shooting at a high school football game where I was able to put the 9-point AF to the test, and it didn’t fail to impress. The camera was quick to snap to focus, and was very accurate in AI Servo mode. Low-light performance was pretty good, and I was easily able to use shots at ISO 3200 after some noise reduction.

The next task I used the 60Da for was as a second camera at a portrait session. I used it primarily with a Canon EF 50mm f/1.4, and after shooting a gray card for a custom white balance, colors were spot on. I shot wide open, and the camera consistently nailed focus – not an easy task with such a narrow depth of field – and I was very impressed with how good the shots were.

Finally, I took the camera out for some birding and macro photography. For the macro shots, I used a Canon EF 100mm f/2.8, and for the birding I used an Orion ED80. In both cases, I got extensive experiences that forced me to realize that I must have a camera with this flip-out, Vari-angle LCD. I’ve grown accustomed to the contortion acts that accompany good macro and birding with a telescope, but that all disappeared with the 60Da. Simply rotating the LCD allowed me to stay in a comfortable position at all times. Words can’t describe how much I love this camera for these types of shots. I didn’t bother with a custom white balance, as the colors were close already and easy to perfect after the fact. As with all my other experiences, noise was low and the detail was rich.

Image 4: Macro of a dragonfly taken with a Canon 60Da and Canon EF 100mm f/2.8 lens.

been suggested that this camera is a compromise between a great astronomy camera and a great traditional camera. While I can see that point, I think it’s fair to say that, for many people, it represents not compromising. Some of us have to make the choice between a dedicated astronomy camera or a camera for family pictures and everyday uses. This camera does both, and more than adequately. Then there’s the simplicity of just having one camera. No need to carry different gear for different occasions – just grab and go.

And consider this: If the percentage of Halpha data capture is all that is limiting your astro imaging success – meaning your data capture and post processing techniques have reached perfection – it’s probably time for you

to graduate to a high-end, astro-dedicated CCD. Until you’ve reached such lofty heights of astrophotography competence, the 60Da will not be your limiting factor.

If there is a compromise, it’s certainly not one sided. You can modify a DSLR yourself and get even more H-alpha data, but you won’t have a warranty should something go wrong.

Then you have to hope that you, or whoever modified the camera, got the sensor back to perfectly orthogonal or you’ll have a whole new set of compromises. Perfect autofocus after removing or replacing glass in front of the sensor? Sure, it’s possible, but I’m skeptical. The day that I received the 60Da, I owned two other modified DSLR cameras, and, out of the three, I’ve still got the 60Da!

Conclusion After using this camera for a plethora of astro- and terrestrial-photography excursions, I must admit that I’m quite impressed. It’s

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An Introduction to Astronomical Filters Part 6 Filters and Video Astronomy

By Jim Thompson

When I first became involved with astronomical filters, my interest was solely for visual observing. I live in a large city where light pollution is a real problem, so I was hungry to find a way of seeing more from my backyard than simply the Moon and planets.

Using light-pollution (LP) filters did help significantly to increase the range of objects I could observe from inside the city, but still the list of possible targets was very short. To be honest, my interest in observing, at least on any sort of regular basis from my home, was beginning to wane.

Then, in November 2010, I was introduced to a new way of observing that blows away the limitations of traditional visual observing: video astronomy. It was on the fairly new but quickly growing live video streaming site, NightSkiesNetwork.com, that I was introduced to observing using a specially designed video camera instead of an eyepiece. I was amazed at the views that were possible and the remoteness of the objects that could be viewed, all from a light-polluted backyard.

Three main things make video astronomy so appealing: (1) full-colour images in

near real-time, (2) a sensor that has a wider spectral response and much higher absolute sensitivity than the human eye, and (3) highperformance video-processing circuitry to manipulate and optimize the image live. I purchased my Mallincam (MC) Xtreme in

January 2011, and have loved it ever since.

Video astronomy is a combination of live observing and imaging, and, as a result, it is able to take advantage of the best aspects of both fields, including the use of filters. No longer limited to viewing objects in the narAstronomy TECHNOLOGY TODAY

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AN INTRODUCTION TO ASTRONOMICAL FILTERS PART 6

Figure 1. Spectral Sensitivity Comparison: CCDs used for video astronomy and imaging in general are much more sensitive than our eye, especially at the red end of the spectrum.

row cyan-green band that our eyes can see at night, video astronomy opens the door to using filters normally used for CCD imaging.

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The most notable changes over eyepiece observing is being able to see hydrogen-alpha emissions from nebulae and being able to see near-infrared emissions from galaxies. Un-

fortunately, astro-video cameras are also more sensitive to the main wavelengths for light pollution as well. Without using filters, an astro-video camera is able to view dim objects that would normally not be possible from inside a city. By effectively applying the right LP filter, however, the views that can be achieved are simply stunning.

Being now able to use filters meant originally for imaging adds to the problem of choosing the right filter. I had to add four new filter categories in order to capture these new additions: H-alpha groups A and B, IR Cut, and IR Pass. The first three new categories are all interference-type filters like the other LP filters, but the IR Pass is an absorption type, essentially a colour filter. I have not included extremely narrow-band filters in my list such as NII and SII filters since the length of the integration time required to use them makes them not practical for live observing.

To compare the performance of filters when used on an astro-video camera I have used the same methodology as I used for visual observing (see my preceding article). I used the

AN INTRODUCTION TO ASTRONOMICAL FILTERS PART 6 same telescope setup, same background lightpollution cases, and same three DSOs. The detector selected for the analysis was the Sony ICX418AKL, the same CCD used in the standard Mallincam Xtreme. The only difference in my analysis was the unit of measure used to evaluate each filter’s performance. SNR was not a good measure of performance since the video-processing circuitry in the camera is able to adjust the contrast and brightness (and thus SNR) on-the-fly. Instead, I chose to use the max predicted difference in RGB level between the DSO and the background. Assuming a 24-bit digital colour system, the maximum contrast in a video image is achieved when the DSO is at the saturation limit (RGB=255) and the background is black (RGB=0). Using the same 2-percent rule from my previous article, the minimum ΔRGB level for detection of the DSO is 5.

The predicted ΔRGB level is calculated using the following equation: ΔRGB = 255 *(1 – (Luminancesky/Luminancesky+DSO)) * C. The constant “C” was used to calibrate my predicted ΔRGB against what I have measured in the past using my Mallincam.

As with the visual analysis, I began with one representative from each of my filter categories: multi-band (IDAS LPS-P2), extrawide band (DGM GCE), wide-band (Lumicon Deepsky), medium-band (Astronomik UHC), narrow-band (Meade Narrowband), OIII (Astronomik OIII), H-beta (Astronomik H-beta), H-alpha (Astronomik H-alpha 6nm), special (Canadian Telescope Moon & Sky Glow), and IR-pass (generic 680nm high-pass).

I did not include IR-cut filters as a separate category, but instead evaluated all the other filters with and without an idealized IRcut: a filter with 100-percent transmission between 400 and 700nm, and 0.0-percent transmission everywhere else. I plotted the predicted ΔRGB values for a MAG +3.5 (LP), +2.3 (Moon), and +2 (LP + Moon) sky, with and without filters.

On bright nebulae, light-pollution filters were found to be very effective at increasing ΔRGB in the image when there was no

Figure 2. Typical DSO Spectrums: Using video astronomy, the observer is able to see things never before possible with just the naked eye.

Moon out. When the Moon is out, the effectiveness of the filters was greatly reduced.

This is consistent with what I have observed using my MC. Medium- and narrow-band

filters perform reasonably well, with the OIII filter being slightly better again. The H-alpha filter provided the best level of ΔRGB, being almost equivalent to the no-filter case under

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AN INTRODUCTION TO ASTRONOMICAL FILTERS PART 6

Figure 3. Comparison of Different ΔRGB Levels: In this simulated image, the relative appearance of different ΔRGB levels is illustrated.

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AN INTRODUCTION TO ASTRONOMICAL FILTERS PART 6 dark skies. In all cases, adding the IR-cut filter to the LP filter improved the ΔRGB slightly, with the biggest improvement showing up on medium-band, narrow-band, OIII, and H-beta filters.

When applied to dim nebulae, LP filters help somewhat, but not enough to bring the ΔRGB level significantly above the detection limit for my telescope setup. The exception is the H-alpha filter, which increased the ΔRGB to a level several times more than what would be achievable with no filter under dark skies. Amazing! Even with the Moon up, the H-alpha filter increased the ΔRGB level above the detection limit. Applying an IR-cut filter did improve filter performance slightly, as was observed for bright nebulae.

When LP filters were used on the galaxy, there was a small improvement in ΔRGB. The medium-band, narrow-band, and Hbeta filters provided the best improvement out of the LP filters tried. More interesting was the large improvement in ΔRGB realized by using the IR-pass filter. This filter was able to produce ΔRGB levels twice that predicted for the LP filters. For all filters, adding an IRcut filter resulted in a significant drop in ΔRGB, the opposite of what was found when viewing nebulae.

I have had an opportunity to test many of the filters in this short list using my MC. I have observed much the same filter performance as predicted by my analysis. The only exception is that my analysis predicts that even with LP filters, galaxies are not detectable with my telescope setup when the Moon is up. In practice, I have found that galaxies are detectable when the Moon is out, albeit at a much decreased ΔRGB, and their view is improved with the use of an LP filter.

This observation varies depending on the surface brightness of the particular galaxy, i.e., low surface brightness galaxies are indeed not visible with my setup when the Moon is out.

The consistency between my predictions and actual observations gave me confidence to proceed with analyzing the rest of the filters in my library.

As in the preceding article, I plotted the

predicted ΔRGB for each filter versus its Luminous Transmissivity (percent LT). Doing so revealed some very definite trends in filter performance. Figure 5 shows a simplified version of the results, identifying the general trend in performance for the different filter categories. In reality there was a large amount of scatter in the results. The scatter is due to the fact that most LP filters, being designed for visual use, do not all pass H-alpha and nearinfrared to the same extent.

Some filters are clearly superior due to their inclusion of good H-alpha and NIR responses in their design.

The plots in Figure 5 also Figure 4. Filter Video Performance by Category: A representashow the shift in filter per- tive filter from each category has been plotted above for a formance when an IR-cut range of LP levels and DSOs.

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AN INTRODUCTION TO ASTRONOMICAL FILTERS PART 6

Figure 5. All Deep-Sky Filters Compared: These plots are a simplified view of predicted performance for all interference type filters for which I have data.

filter is added: up and left on nebulae, down and left on galaxies.

On bright nebulae, H-alpha and OIII filters appear to provide by far the best contrast. With no Moon, narrow-band H-alpha filters edge out OIII slightly, to the point of getting saturation in the nebula image when the integration is maximized. When the

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Moon is out, OIII filters seem to edge out Halpha. Narrow- and medium-band LP filters also provide a good improvement in image contrast at a much decreased integration time over H-alpha and OIII filters.

Dim nebulae benefit from LP filters much like bright nebulae do. The performance of OIII filters is reduced to the point of

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being useless on this type of target, but Hbeta filters step up to fill the roll. Again, Halpha filters are the best performers for contrast over H-beta and narrow-band filters, at the cost of longer integration times. When the Moon is up, it would appear that H-alpha filters are the best bet on dim nebulae.

The performance of LP filters on galaxies was the most scattered plot of them all.

The response of LP filters in the NIR band seems to play a large part in how well each filter performs. Of the conventional multiband LP filters, medium-band filters seem to perform the best. I was surprised at how well H-beta filters were predicted to perform. This result prompted me to include an H-beta filter in a recent test with my MC, the result being my prediction seems to be true.

Before you run out and get an H-beta filter, I should point out another more interesting discovery: high-pass filters, specifically reds and infrareds. In Figure 5, an outlier has been marked, the Lumicon H-alpha Pass filter. This filter is essentially a dark-red highpass filter. The performance of this filter on galaxies encouraged me to include colour filters in my analysis, including infrared highpass filters. The simplified plot of colour filter performance is shown in Figure 6. I have left out lines for colour groups that did not improve the ΔRGB by a significant amount.

On bright nebulae, there was some improvement realized from the blue and green filters, but not enough to make them competitive with traditional LP filters. On dim nebulae, there is an improvement predicted using red and the shorter wavelength infrared pass filters, especially when combined with an IR cut filter. This is not surprising since this filter combo essentially makes a broadband H-alpha filter. The really interesting result was the performance of red and infrared filters on galaxies. Infrared-pass filters are clearly superior to LP filters, with peak contrast occurring for an IR-pass filter with a cutoff wavelength around 800 nm. If you don’t mind black-and-white images (you’ll have to put your Saturation = 0), IR-pass filters may be the way to go on galaxies. Note that if you want to see H-alpha regions in some of the

AN INTRODUCTION TO ASTRONOMICAL FILTERS PART 6 closer galaxies, you’ll have to select the appropriate high-pass filter (i.e., a filter that does not cut off 656nm).

It appears that IR-cut filters are beneficial when observing nebulae, but not galaxies. For galaxy observing you want your camera to see all the IR it can. IR-cut filters were not originally designed for reducing infrared LP; they were made for improving image quality in astrophotography.

Refracting type telescopes and lenses are designed to focus all the colours of the visible spectrum to a single point in space. Early lens designs are not perfect at focusing all the wavelengths of light, resulting in a visible blue-red halo around bright objects called chromatic aberration. These early lens designs are still used today in some achromatic camera lenses and telescopes because they are easy and inexpensive to make. When people began using this type of lens for astrophotography, they found that their Hα sensitive films (and more recently DSLR and CCD detectors) produced slightly out-of-focus images and bloated stars. The cause was the contribution of infrared light to the image, which the lens is not designed to focus at the same point as the visual band light. The simple answer to this problem was to add an IR-cut filter. Ultraviolet light results in a similar blurriness to the image, so most IR-cut filters block UV as well.

The additional sharpness and reduction in star bloat achieved by using an IR-cut filter in astrophotography can also be realized in video astronomy. In my experience, the improvement in image sharpness and reduction in star bloat is quite significant when using an achromatic scope or lens. With an apochromatic lens, the improvement is less pronounced since this more complex design does a better job of focusing all the wavelengths of light. On a Schmidt-Cassegrain design, the improvement is just barely noticeable since the only refraction that occurs is in the corrector plate. I do not know from experience, but I assume that the benefit realized from using an IR-cut filter on a Newtonian reflecting telescope would be only that provided by the reduction in infrared light pollution.

Figure 6. Colour Filters Compared: These plots are a simplified view of the predicted performance of colour filters. Only colour groups that showed a significant improvement in ΔRGB are shown.

It was mentioned in one of my earlier articles that interference type filters are sensitive to the angle at which the light passes through the filter. As the angle increases, the response of the filter widens and shifts down in wavelength. I’ve tested this behaviour using a very short focal-length lens, and have found that as long as you stay slower than f/2 (scope-filter-camera) or a field of view < 30 degrees (filter-lens-camera), you should be fine.

The final thing to discuss is percent LT. This filter characteristic defines the percentage of the total incoming light that is getting to the camera detector. In all cases, the filters that provide the best image contrast are also the ones with the smallest percentage of LT. Thus, if you plan to use these top-performing filters, you must be prepared to deal with the large increases in integration time. If you plan to use filters with percentages of LT less than

20, you will need to consider guiding of your telescope or at least using an equatorial mount.

Based on the results of my analysis, LP filters can dramatically improve the images produced by astro-video cameras. A good all round performer seems to be a medium-band filter with good H-alpha and infrared response. I recommend starting there, and after you have played with that filter for a while and know what it can achieve, you can branch out into more specialized filters. I also recommend having an IR-cut filter, certainly to improve the view with refractors, but also just for an extra boost to your views of nebulae.

For questions or access to more details of my results, contact me at karmalimbo@yahoo.ca, or visit my website at http://karmalimbo.com/aro.

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The Aggas 36-inch Dobsonian A Custom ATM Newt for the ApacheSitgreaves Center for Astrophysics

By Steve Aggas

Located in a world-class dark-sky site on top of the Colorado Plateau in northern Arizona, amid neighbors such as the Lowell Observatories at Flagstaff and Anderson Mesa and the 4.2-meter Discovery Channel Telescope just completed in Happy Jack, the Aggas 36-inch telescope at Apache-Sitgreaves Center for Astrophysics in Overgaard, Arizona, recently became operational and not only provides delightful views, it’s a delight to use.

I built the 36-inch telescope in my garage in Gold Canyon, Arizona, using mostly run-of-the-mill tools, and then transported it in a moving truck to a dark-sky site in Overgaard. While initially used primarily for visual observing, the telescope has been upgraded very recently with servo motors for tracking the stars.

There are Pro-Am activities that will keep me busy observing and building astronomy-related equipment. A custom spectrograph is currently in construction to match the mirror’s focal ratio of 4.5. The 20-pound device will bolt to the upper cage.

How did this 36-inch telescope come about? Let’s just say, it helps that my wife is a fellow amateur astronomer when she has the final say in the appropriations committee meetings!

Planning the Project I started planning this project years ago, accumulating parts over a 15 year period, knowing that, one day, I’d built a big telescope. For instance, the mirror’s sling is 1/4-inch stainless rigging from my Dad’s sailboat. He upgraded, I saved it and

eventually used it.

When a suitable primary mirror became available, I started planning the project in earnest, designing it in Microsoft Excel. If you don’t already have computeraided drafting software, Excel is a great solution.

One can make unique shapes in Excel, creating scale representations of a project, and, if you compare the design in Image 2 to the actual telescope, they’re quite similar.

I’ve used Excel for many projects: the 36inch f/4.5, a 6-inch f/3.5, and, for the classic spectrograph.

From the execution of the first Excel drawings to completion of the usable telescope involved thirteen months of work, with the final four months of construction consuming every night after work and most weekends.

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THE AGGAS 36-INCH DOBSONIAN The Mirror Cell The mirror cell was the first major component that I completed, and I did that work before the primary mirror arrived, substituting a trace drawing of the mirror to confirm placement and verification of hardware.

The mirror cell integrates some unique features. It was constructed of 3inch square-steel tubing to minimize flexure and has fans installed at the far left and right of the outer frame to push air through the tubular steel frame and eventually exit blowing air onto the back of the mirror. Additionally, there are twelve fans that blow air into the hexagon honeycomb structure and six 5-inch fans incorporated into the back mirror box cover to pull cooling air down the tube, past the mirror and out the back. As large as this telescope is, these six fans in the back mirror cover pull the entire telescopeâ&#x20AC;&#x2122;s volume of air through the telescope every 18 seconds. Three other fans mounted on the inside sidewall of the mirror box blow the primaryâ&#x20AC;&#x2122;s heat bound-

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ary layer away.

Bolted to the main tubular frame of the cell are two support-beam structures at 45-degree angles, shown at the bottom of Image 4, with linear bearings that contact the edge of the mirror. The mirror can move for alignment purposes but is confined to motion that is only on-axis as the collimation bolts are turned. This guarantees the mirror will stay centered in the mirror cell, which position was carefully measured and set when the mirror was first installed.

As mentioned, the cell uses stainlesssteel cable for the sling, and critical for sling support is placing it accurately around the mirror edge by calculating the center of gravity from front to back edge of the mirror, taking into account that the mirror has a curved front surface and, also, its varying thickness, as well as its backside contours.

In this case, the mirror is 6-inches thick, but 5-inches of that is a honeycomb pattern with 19 large hexagon holes. When completed, the mirror cell weighed 250

pounds.

Attached to the back of the mirror cell is the main control box. (See Image 5) A 50-amp circuit breaker is the main disconnect between the control box and the deep-cycle batteries that are positioned 25 feet away when the scope is set up in the field. 4-gage welding cable feeds the control box. Such large-gage wire was used to minimize the voltage drop over those 25 feet. The control box has a battery-bank voltage-monitoring display built into it, and I wanted the voltage reading to match within 0.1VDC the other display connected at the batteries.

The system includes custom op-amp circuits which convert sensor signals into display values to show the relative humidity within the mirror box, and there is a thermocouple meter next to the control box to display the temperature at the points of five different thicknesses of the mirror, plus outdoor air temp. And, of course, there are control switches for cooling fans, heaters, etc.

THE AGGAS 36-INCH DOBSONIAN

Image 1: The author using his 36-inch ATM Dobsonian.

Image 4: The primary-mirror cell assembly.

Image 2: Drawings of the 36-inch Dobsonian executed in Mircrosoft Excel.

Image 5: A control box is mounted to the back center of the mirror cell.

Image 3: Basic primary-mirror cell structure with trace drawing in place for locating hardware.

Image 6: Remotely operated motors are mounted on to each of the three collimation bolts.

Image 7: Detail of mirror-box Image 8: Upper view of finished mirror box with interior layout showing the two mirror cover in place. points of connection of the truss pole.

Image 9: An adjustable router jig was used to cut the upper-cage rings and primary-mirror box bulkhead plate.

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THE AGGAS 36-INCH DOBSONIAN Remote Collimation One feature required to make the 36inch Dob a one-person-portable telescope is its remote collimation feature. Where one would typically see collimation knobs, motors are instead positioned on springloaded mounts to keep tension on the sprocket-pulley systems that rotate the collimation bolts. (See Image 6) The motor wirings are tied into the control box and controlled by a hand paddle. Its 25-foot cord allows primary collimation while standing on a ladder at the focuser.

The hand paddle has three momentary switches in an on-off-on configuration, with one switch allocated to each of the three motors. Adjustment of the primary is done while looking directly into the eyepiece. When collimation is complete, the master switch disconnects power to the toggles so the user doesn’t acciden-

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tally move the primary. The hand-paddle cable is then unplugged and stowed.

The Mirror Box With the primary-mirror cell completed, the next task was construction of the mirror box that surrounds the primary mirror and cell. I chose wood, specifically 1-inch Baltic Birch plywood, because of the high-frequency dampening characteristics that wood or plywood provide.

Whereas metals ring, wood does not.

Starting with a pallet of sixteen, 5-foot square sheets of 1-inch thick Baltic Birch (each weighing 86 pounds) I carefully laid out the lines of the side panels and the bulkhead plate that contains the mirrorcover disk. The mirror box’s bottom perimeter would surround the mirror cell and connect to it using carriage bolts. The interior corners of the mirror box were reinforced with long, triangular shaped pieces of White Oak and the walls extended above the bulkhead plate by 6 inches.

The reason for this extension is that I wanted the Surrier-truss poles to have a total of three points of contact when the scope is fully assembled: (1) near the mirror cell (but not touching), (2) the wall just above the bulkhead plate (so the poles would be held mechanically stable by just these two points before the upper cage was installed), and (3) at the upper cage where two poles would meet (but, again, poles not touching).

The lower pole connection is composed of a 3-inch length of 3/8-inch thick angle iron and is bolted to the mirror box wall just above the mirror cell. The other face of the angle iron faces upwards at a slight angle and is equipped with a 3/8-16 threaded stud that the pole threads onto.

The poles are 2-inch (outside diameter) aluminum with 1/8-inch wall thickness, and both ends have pressed-in 3/8-16 threaded inserts. Each pole is first passed through the clamp block above the bulkhead plate, then passes through the bulkhead plate and screws onto the bottom angle iron stud. Finally, the clamp is tight-

ened securing that pole.

The pole mechanical connections at both ends also double as the electrical connections. The control box wires are routed and attached to the angle iron, and, within each of the pole seats on the upper cage, there are fender washers with wiring soldered to them. When the cage is set on top and bolted, the circuit is complete. Unused truss-tube wires are just bundled within the cage and zip-tied against the cage’s interior wall for future use. Wires in use within the cage are routed around the cage interior as needed using sticky-back anchors.

The Upper Cage Assembly With so many large circular features to cut, I built an adjustable router jig to hold a true circle of up to 54 inches in diameter for cutting the cage rings, as well as the mirror opening in the bulkhead plate. I managed to burn out a router while cutting these pieces. Granted, I was trying to plunge and route 1-inch thick Baltic Birch in a single pass! Because I had spent so much time making a circle jig for the original router, I bought an identical one to replace it, which, fortunately, lived to finish the scope.

As mentioned, each truss pole is a current-carrying conductor used in bringing either a signal, voltage or ground connection to the upper cage. The upper cage power jacks, used for eyepiece dew-heaters and such, are on a 5-amp circuit breaker, just one of the many individual circuit breakers powered with the 50-amp main.

There are truss tubes currently dedicated for powering the two secondary mirror fans that bring cold air into the holder, as well as the thin-film heater strips adhered to the secondary mirror’s backside should the dew point start to rise and the mirror require some warming.

For power to reach the secondary mirror, each of the spider vanes is electrically isolated using poly tubing surrounding each screw that mates the center cross-hub with a vane and also using PTFE-coated Nylon sheeting wrapped around the vanes’

THE AGGAS 36-INCH DOBSONIAN

Image 10: Thin-film heater strips are attached to the backside of the secondary mirror for dew control.

Image 13: LEDs are positioned near the focuser to indicate which filter-slide position is currently in use.

Image 11: The secondary heater strips and fans are powered and controlled by three wires that are, in turn, powered by electrically isolated spider vanes.

Image 14: The filter-position indicator lights.

Image 16: The UCAâ&#x20AC;&#x2122;s integrated eyepiece holder is shown at the top of this image.

Image 12: Electrically isolated spider vanes transfer power to the secondary heater strips and fans.

Image 15: A remote touch-screen display is positioned near the eyepiece and controls a laptop mounted near the mirror box.

Image 17: Sections of White Oak board were cut to length, mitered and then glued end-to-end to form rough blanks for the large altitude bearings.

Image 18: A sanding drum and drill press were used to form perfectlycircular altitude-bearing blank.

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THE AGGAS 36-INCH DOBSONIAN ends.

As I mentioned, there are two fans installed inside the secondary-mirror holder which pull in cooler air and blow it past the mirror’s backside and then exits through exhaust ports, but there are also two more fans mounted on the inside cage wall to blow across the front face of the secondary mirror. The secondary mirror, with a minor axis of 6-inches and a thickness of 1 inch, also has a thermal boundary layer that must be removed for optimum performance, just like that of the primary.

The Filter Slide There is one electrical system not tied to the main control box, and that is for filter-slide indicator lights. Those indicator

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lights are 6-mm LEDs mounted in 10-mm holders, each labeled for identification of a specific filter type. (See Image 13) They are only partially lit for unused filters (filters not in the light path) and brighter if a filter is in that position’s light path, and all powered by an external jack mounted on the underside of the Telrad finder using the batteries of that finder. When the Telrad is attached to the scope, the filter slide electrical connection is automatically made.

There’s also a dial potentiometer with an off position mounted in the Telrad for adjusting the indicator lighting systems’ overall brightness to personal preference.

The filter slide itself is integrated directly behind the focuser and is operated by a rotary knob on the outside of the cage

positioned next to the focuser. (See, again, Image 13) Rotating the knob moves filters in and out of the light path. As the filters pass behind the focuser and come into position, a mini-limit switch on the slide is activated which, in turn, turns that filter’s indicator light slightly brighter than the rest. The system is very intuitive, because you can read the labels of the filters on the LED holders and see which filter is currently used without having to ask anyone.

(See Image 14) Computer-aided astronomy is the norm, with planetarium software replacing printed star charts. On the 36-inch scope, there’s a laptop bolted to a plate on a truss tube near the mirror box and connected to it is a remote touch-screen display that’s

THE AGGAS 36-INCH DOBSONIAN

Image 19: Arranging the spoke patterns. Image 20: 1-inch holes were drilled at all points of spoke intersection.

Image 22: The full-circle altitude-bear- Image 23: While visually appealing, ing assembly was cut in half to form the the spoke pattern has a function: suptwo separate bearings. porting the flying arc of each bearing that extends past the mirror box.

Image 25: Shown is the underside of the ground board with electrical connection.

Image 21: The individual spokes were then installed with the gather ends fitting into slot pockets.

Image 24: The ground board transfers power to the rocker box via two copper rings.

Image 26: Power is routed to the ground board Image 27: A frame of 1-inch square by wires that pass through one of the patio tubing was constructed to stabilize the blocks that form the telescopeâ&#x20AC;&#x2122;s observatory ground board. foundation.

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THE AGGAS 36-INCH DOBSONIAN

Image 28: The steel stabilizer frame is shown installed on the ground board.

located near the eyepiece. (See Image 15) With the stylus provided, one can perform any action within the planetarium program that they’d do on the laptop itself, or any other program for that matter. This setup allows complete computer control right at the eyepiece. I built a flip cover to block the light from this display when it’s not in use, but it’s very handy when you’re 12 feet in the air and want to identify an object. There’s also an eyepiece holder mounted on the cage, capable of holding five 2-inch barrel eyepieces and two 1.25inch eyepieces. The amount of weight added from an entire eyepiece set has no effect on balance with a scope like this.

There’s very little motivation to come down the ladder except when it’s time to

Image 29: A custom “Rover” cart was constructed for moving the lower assembly as needed

do another automated go-to and reposition the ladder.

The Altitude Bearings The rocker box, the portion of the scope that rotates the whole scope in azimuth and that allows the mirror box to pivot in altitude, has sidewalls composed of three individual Baltic Birch boards cemented together. The resulting 3-inch wall thickness transfers the scope’s weight without flexure.

The altitude bearings of the scope, cradled in the arc of the rocker box wall, are arcs of 3-inch thick White Oak. To me, altitude bearings bear heavily on the esthetics of a Dobsonian. Those of the 36-inch scope feature Cherry Wood spokes in a

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Astronomy TECHNOLOGY TODAY

radial burst pattern. Individual White Oak sections were first cut to length; the ends of each were then mitered to the proper angle and glued end-to-end to form a rough circle, alternating where the ends met for each layer to create a roughly 5-inch-wide ring blank. (See Image 17) Next, the center axle was installed, and the outer portions were routed off using that same circle jig mentioned earlier, leaving a roughly 3-inch square ring structure.

The finish grinding of the altitude bearing rings was done after the outer material was routed off but the inner axle was still intact.

(See Image 18) 50-grit Garnet paper on a drill-press-mounted 4-inch sanding drum made forming perfectly-round altitude ring easy. I was astonished how fast that

THE AGGAS 36-INCH DOBSONIAN Garnet chewed the White Oak into sawdust.

Next, the Cherry spoke pattern was laid out, and then 1-inch holes drilled into the inner arc, into which the spokes would eventually be glued. (See Images 19, 20 and 21) This is one step that left me scarred! A couple times, the Forstner bit jumped out of the hole and rolled across the top of my hand while trying to drill angled holes. There are a couple holes that are about a 10-degree angle to the arc.

Drilling straight into the arc is no problem; drilling at an angle is tough.

I cut pockets in the side of the bearing from which all of the spokes would radiate and contoured them so that the spoke ends would be hidden when the altitude bearings were mounted on the mirror box.

The full-circle altitude-bearing assembly was then cut into halves to form the two separate bearings. (See Image 22) Each bearing was bolted to the mirror box wall, but there are no bolts to strengthen the arc past the edge of the box, so the spokes alone must provide the compression strength needed when observing lowaltitude objects. (See Image 23) The Rocker-Box/GroundBoard Assembly The rocker box floor is 2-inches thick and contains an electrical power-transfer system composed of spring-loaded pins within the power distribution box. This box also has three sockets on 20-amp circuit breakers. The pins ride on copper rings coated with conductive grease and that are attached to the ground board. The rings electrical wiring continues through the ground board to a 50-amp circuit breaker and a cable quick-disconnect mounted on the edge of the ground board’s underside.

The observatory’s underground wiring comes up under the scope through patio blocks and has the mating cable quick-disconnect. (See Images 24, 25 and 26) Extended use of the original groundboard assembly eventually revealed gradual increases in the force needed to move the

scope in azimuth. There was enough flexure to require adjusting the center lift system even further to transfer the same amount of the scope’s weight to the central pivot bolt, which reduced the weight on the three outer bearing surfaces on which the scope rode, and, in turn, reduced the force needed to move the scope. While initially stiff enough, the rocker box floor wasn’t good enough in the long run. After numerous adjustments, the center was quite high compared to the edge, and the spring-loaded electrical rods that ride on copper rings were not making good contact.

To resolve this, I built a frame composed of 1-inch square steel stock and inserted it on the floor of the rocker box.

(See Images 27 and 28) The center of the frame structure was purposefully made lower than the edge and welded this way, so that after installation and the full weight of the scope was applied, the frame would then be flat and so would the rocker box floor. A website called Engineer’s Edge was very useful in calculating flexure under a variety of scenarios. Once the frame was installed and adjusted, no further adjustments have since been needed, and the azimuth motion moves with the same force every time I use the scope. It’s very critical that the force required to move the scope stay the same when considering installing a telescope drive system such as ServoCAT. The Rover Hardware With a ground-board/rocker-box/ mirror-box/primary-mirror assembly weighing a total of 1150 pounds, I solved the problem of moving the assembly by creating a mobile platform. A steel rectangular frame of 3/8-inch angle iron was cut such that two sides of it would bolt to the outside walls of the rocker box, then the remaining two sides of the steel frame would bolt to the corners of the first two pieces. A motorized scissor jack lowers the dual axle, thereby lifting the scope on one end, and a trailer jack lifts the other. The

trailer jack was modified to allow steering, and the dual-wheel assembly was motorized with drive chains. The “Rover” makes for a funny looking car, but I was happy with it! (See Image 29) We used the Rover to move the lower assembly into a rented truck and to move it from the truck and into position at its permanent home. Once the scope was completely assembled at the observatory site, the Rover framework was removed and the computer attached along with the Telrad and remote touch-screen.

The scope was finally ready for the “first light” views most people think of with new scopes. Panning around Abell 2065, the Corona Borealis Galaxy Cluster, was awesome with 19 galaxies seen with direct vision and another 20 objects detected as galaxy cores (not as sharp as stars), for a total of 39. Not bad for objects about a billion light years away!

For more information, please feel free to visit my website at www.darksky observing.com.

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Driving Stepper Motors AN ATM SOLUTION

By Rick Saunders

When putting together all of the equipment needed for imaging, there are many places that a stepper motor could come in handy. Focusing and moving masks (focusing, flat, etc.) in or out of the optical path come directly to mind.

Commercial stepper-motor implementations are usually single-purpose, i.e., a focus controller won’t move masks and vice-versa. If you’re handy with a soldering iron you can build your own controller for a few dollars and tailor it to your needs.

I started out on this project thinking that it would be nice to be able to move a Bahtinov mask into and out of position remotely. While this could be done using regular DC motors, it would either take some fancy electronics (with microswitches to limit travel) or I’d have to be in sight of the telescope. A stepper motor that I could tell “turn clockwise 500 steps” would be much simpler and more accurate.

The first consideration with this project was whether to design it for a unipolar (5-wire) or bipolar (4-wire) motor. There are other styles of motors with more or less wires, but these are the most common configurations. I had both on hand and eventually decided on the bipolar part only for simplicity of design.

Next I had to decide which chip to use to actually power the motor. There

Image 1 - Components of Stepper Project

are dedicated chips, but these can be expensive and difficult to find, so a more generic chip such as the L293D dual Hbridge chip seemed to be the best way to go. The L293D takes care of setting the changing polarities going to the motor’s two sets of terminals and will be connected to an Atmel micro-controller programmed using Arduino tools.

I like to use the Arduino platform for projects. Arduino is a hardware and software solution to programming micro-controllers. The development boards (Image 2) are cheap and the software is free. The Arduino programming

environment uses a language called Wiring which is just C++ wrapped in a simplified interface. This comes with a set of pre-written libraries for doing things like talking to an LCD display or controlling a stepper motor. Once programmed, the micro-controller can be moved from the development board onto a circuit board of one’s own creation, which is what I did with this project. A twist that I added on my board is that I’ve added an “In Circuit Serial Programming” interface that allows me to write the chip’s firmware in Arduino’s Wiring and then use a different program-

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DRIVING STEPPER MOTORS

Image 2 - Arduino Board

mer to write the code to the chip as it sits in the board. It just makes things a bit simpler.

There are many different “shields” that plug into the sockets on top of the Arduino board that do chores like talk on Bluetooth or Ethernet, provide an interface to GPS, or to handle motors. The most common of the motor shields is

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Image 3 - Stepper Wiring Diagram

that provided by Adafruit, which not only sells the motor control board but also provides libraries and software. The original Arduino Focuser Project by Eric Holmes was designed around the Adafruit board. The project I am describing is command compatible.

The board in this project was built on perf-board. For those who have never

used it perf-board, it has properly spaced holes to plug components into and solder in place. Any connections are done using fine-gauge wire. It can look messy, but it’s a good way to debug a circuit and, if it works, the board can be used as is.

I wanted to be able to talk to the board via USB, which meant that I’d

DRIVING STEPPER MOTORS

Image 4 - Front of Autofocus-Board Layout

have to incorporate a USB-to-serial chip and a connector. As perf-board is for “through-hole” parts, and there are none of these available for USB, I purchased a “breakout board” from SmartFun which provides some pins to mate the surfacemount USB chip to a through-hole board.

The first step was to design the circuit or create a schematic diagram. This would give me the “map” of where the wires on the perf-board would be going.

I created the schematic using the free version of a package called Eagle that allows you to both create schematics and to lay out boards. I needed to incorporate two chips, four connectors, the SmartFun board and a few parts to make the microcontroller happy. The schematic was turned into the wiring diagram shown in Image 3.

Image 5 - Back of Autofocus-Board Layout

Once I knew where the wires were going, I could gather together my components and start soldering. I’ve found that it’s much simpler to layout all the parts on a perf-board, get them where they’re wanted, and then tape them all in place and solder them in a batch. A good iron with a fine tip is required as it’s best to keep the solder “blobs” small. The top and bottom of the board I created are shown in Images 4 and 5.

Image 4 is the top of the stepper control board. The SmartFun USB breakout board is on the left and the rest of the connectors to the right. The micro-controller and motor-control chip receive their operation power from the USB connection. The power connection on the right of the board is to provide power to the motor (not many are 5v, and they would probably draw too much

current from the USB). There is a connector for the 4-wire motor and another four pin connector that allows a pair of buttons that can enable the motor to spin in either direction for initial setup. The USB has to be plugged in and working for the buttons to function.

The ICSP interface allows me to program the micro-controller on the working board.

The top of the board looks pretty clean. Only a few wires needed to be brought out to the top side of the board, and this is only to keep things simple.

The bottom of the board (Image 5) is where all the connections are made and, to one not familiar with these, may look bewilderingly complex. Believe me, it’s not. Most of the connections could be done with wire of smaller size than I used, but I did with what I had available.

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M 1 2 3 4 5

DRIVING STEPPER MOTORS

Image 7 - Micro-Controller Outputs for Bipolar Stepper Motor

Image 6 - Stepper-Board Schmetic

If you’re going to do a project like this, get some very thin wire for carrying “signals,” i.e., low-current connections as between chips. Use larger size wire where some current carrying capability is needed such as between the motor control chip and the motor, etc.

After all of the wiring was placed and the board tested for short circuits using a multi-meter, it was time to start programming. At first, I used one of the provided Arduino examples to load the chip and see if the motor actually turned. This little bit of firmware actually just spins

SAMPLE CODE: 1#include <Stepper.h> // initialize the stepper library on pins 2 through 5: Stepper myStepper(200, 2, 3, 4, 5); void setup() { myStepper.setSpeed(60); Serial.begin(9600); }

// Set the speed to 60 RPM // Start serial communications at 9600 bits/sec

void loop() { Serial.println("clockwise"); // Print clockwise to the serial port myStepper.step(stepsPerRevolution); // Spin the motor then wait ½ second delay(500); Serial.println("counterclockwise"); // Print counterclockwise to the serial port myStepper.step(-stepsPerRevolution); // Spin the motor the other way then wait ½ second delay(500); }

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Astronomy TECHNOLOGY TODAY

the motor one way, pauses, then spins it the other way. It was a simple method of testing the board.

Shown in the box to the left is some example code to show you how simple it is to program in the Arduino environment.

As you can tell, the programming is fairly straight forward in Wiring.

The autofocuser code for the board in this project is quite a bit more complex and is therefore too long to include in this article. I will provide it on-line. Look for a link at http://www.togastro .com/ozzzy.

There will also be links to the Eagle schematic which can be used to create a board layout for etching. Other useful links include: Sparkfun USB breakout board: www.sparkfun.com/ products/718 Arduino Diecimila development board: http://store.fungizmos. com/items/180 AdaFruit: http://adafruit.com Arduino Focuser Project: http://ejholmes.github.com/2010/03/28 /the-arduino-focuser.html

The Great Atlas of the Sky Is Biggest Really Best?

By Gary Parkerson

In astronomy, bigger is often better.

And if bigger is better, then it stands to reason that the biggest should be best of all.

Of course, digital technology is changing how we use astronomical equipment and thus our concepts of size, so the bigger-isbetter presumption may not now always hold, especially when the subject is printed star atlases. And Piotr Brychâ&#x20AC;&#x2122;s Great Atlas of the Sky is not only bigger, it is, to my knowledge, the largest ever printed for commercial distribution.

The Pages The atlas consists of 296 maps printed on the front and back of 148 pages measuring 17 by 24 inches (43x61 cm). To put that into context, that is 419.3 square feet of paper or about the floor space of a standard two-car garage. Buy two of the atlases (because the charts are printed front and

back) and you could paper the walls of a room measuring 26 by 26 feet without repeating a single chart and for far less than you are likely to spend on traditional wall paper. Now thereâ&#x20AC;&#x2122;s a thought!

The scale of the maps is 1.38 inches (35 cm) per degree, and each chart covers an area of 10 by 15 degrees. At this scale, the moon at perigee would measure more than 3/4 inch in diameter!

The pages are of high-quality gloss stock resulting in crisply delineated stars, symbols and lines. The stellar-magnitude scale ranges from -1.5 to 12 in ten increments. Double and multiple stars are indicated, and individual components are plotted if their separation is greater than 36 arc seconds. Galaxies are denoted by a foursymbol scale and a scale of three symbols is dedicated to globular clusters. Traditional symbols are also dedicated to open clusters,

planetary nebulae and bright nebulae.

Galaxies of diameter greater than 2 arc minutes and clusters and nebula of diameter greater than 5 arc minutes are plotted with symbols that reflect their individual sizes and shapes.

2,430,768 stars are plotted to limiting magnitude of 12, and 70,000 deep-space objects are also plotted. More than 130,000 stars are accompanied with the Greek letter assigned by Bayer or the numbers used in the Flamsteeed and Hipparco catalogs, as well as sysmbols for all variable stars in the GCVS and NSV catalogs.

The Binder The binder measures approximately 14.5 inches (36.8 cm) wide by 19 inches (48.3 cm) tall by 2.5 inches (6.3 cm) thick and features a zipper closure. An internal front diagonal pocket holds the accessories

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THE GREAT ATLAS OF THE SKY

Image 1 - Map Number 1, the North Pole. Visit http://www.greatskyatlas.com/e2.html for an enlargeable version of this image.

and four large “D” snap rings secure the chart pages, which are stored in the binder pre-folded in half. The binder feels like high-quality leatherette, and the fit and finish are excellent – worthy of a star atlas of this stature.

hold a folded chart. The grid film displays four angular scales along with stellar magnitudes. The plastic stock used for both is heavy enough to withstand a lifetime of regular use, and the print on the grid film is notably fine and sharp.

The Accessories The atlas includes two important accessories: a clear-plastic sleeve that protects individual pages when used in the field and clear-plastic grid film for locating precise coordinates between the coordinates plotted on the charts.

The protective sleeve measures approximately 13.3 inches (33.8 cm) by 17.9 inches (45.5 cm): large enough to

Some Assembly Required The atlas is delivered with its pages safely wrapped in separate packaging and nestled within the leatherette binder, but not installed onto the binder’s four D rings.

The owner is therefore required to assemble pages into the binder, and I found myself doing so with more than a little reverent ceremony, as befitted the quality and status of this Great Atlas.

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The Packaging The Great Atlas arrived in perfect condition thanks to its careful packaging within double boxes. Every element was well protected, and it’s hard to imagine the contents being damaged during even the most protracted shipping route.

Impressions I practiced law for a couple of decades before that industry was digitized along with most others and still resort to printed books when doing serious legal research.

Ditto real estate title work. Yes, digital indices are faster and, perhaps, even more thorough for those who are better acclimated to that mode of content delivery,

THE GREAT ATLAS OF THE SKY but, although I rely on digital tools daily in most other aspects of work and life, I resort to the comforting familiarity of print when the stakes are highest. Similarly, when planning observing sessions or star hopping to the smallest targets, I resort to printed charts when success is important to me.

I weighed the Great Atlas at just less than 14 pounds, which is a lot to carry into the field, but that’s not how I used it. Instead, I left the atlas binder in my van and only carried individual charts to my observing table as needed, storing them in the included protective sleeve when in use. Because using the atlas regularly involves removing and reinstalling individual charts, I would eventually apply reinforcement stickers to the four holes in each of the pages, not that any showed undue wear from my extensive use of the atlas, but just to ensure against inadvertent damage.

Why would you need an atlas that

plots stars to the 12th magnitude? Well, consider this scenario: A recent outing consisted of observing a stellar occultation by a minor asteroid using an 8-inch telescope at an site that offered magnitude-5.5 skies, so my telescope-aided reach was approximately magnitude 12. Locating the star in question first on the appropriate Great Atlas chart therefore greatly aided in identifying the star patterns of the immediate field that contained my target.

Given my connection to this print magazine, it’s little surprise that I have retained a strong affinity for print well into the digital age. I suspect I’ll always use print charts in the field, no matter the sophistication of the digital devices and planetarium programs, if only to supplement those amazing digital tools. But, I would want to own the Great Atlas of the Sky even if I never carried it into the field, for the same reason that I use and display other significant references in my home and office. The

Great Atlas of the Sky is beautiful and impressive and represents well the reverence I feel for astronomy. The shear scale of the night sky is often hard to communicate, but the Great Atlas comes closest to doing so than any other star chart I’ve had the pleasure of using. So, even if it never left my coffee table, I’d consider it a wise purchase, not that I’d ever relegate anything as useful to the coffee table!

The Great Atlas of the Sky was provided to ATT by Manish Panjwani, owner of Agena AstroProducts, from which company the atlas is currently available for $139US, including shipping within the USA. I rarely comment on prices, but given what this atlas is, as well as what it represents, this seems a remarkably small price for such a remarkably impressive resource. Bottom line: If astronomy is as integral to your individual identity as it is to mine, you will not be disappointed in this investment.

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The Arizona Science & Astronomy Expo

Attending the Inaugural 2012 Tucson ASAE

By Gary Parkerson

Alan Traino, former ringleader of the Northeast Astronomy Forum (NEAF), has applied his years of experience at planning, promoting and running that world’s-premier astronomy event to the creation of the Arizona Science & Astronomy Expo (ASAE), the inaugural edition of which was presented this November 10 and 11 in Tucson, Arizona. The show was held at the Tucson Convention Center, which dedicated two floors of its impressive facilities to ASAE activities. And there were a lot of activities!

Speakers included Astronaut Donald Pettit, who recently returned from a 198-day tour of duty on the International Space Station, as well as famed Astronaut Story Musgrave. Presenters also included Dr. Steele Hill of ESA’s and NASA’s Solar and Heliospheric Observatory, Dr. Phil Plait, “The Bad Astronomer,” who discussed Myan Prophecies, Geoff Notkin of the Science Channel’s The Meteorite Men, Dr. Carin Bondar, Biologist with a Twist, Adam Block of the Mount Lemmon Sky Center, Dr. Melissa Morris, a presenter on the event’s meteorite panel, Dr. Pamela L. Gay, presenting Solar System Exploration from Your Desktop, and Stephen Ramsden of the Charlie Bates Solar Astronomy Project. Given the feedback we received from the thousands who attended the event, this star-packed roster was as entertaining as it was informative, leaving many visitors actively anticipating who might be on hand for the second edition of ASAE. Events associated with this first ASAE included tours of the University of Arizona’s famed mirror lab, remote viewing from the Mount Lemmon Sky Center and an imaging

workshop presented by its resident astrophotograph-guru, Adam Block. The Kitt Peak National Observatory also hosted tours. Science exhibits included many provided by NASA, the James Webb Space Telescope project and the Challenger Space Center Arizona Solar-System Planet Program. There were also regular planetarium shows throughout both days.

If there was a dark cloud over the event, it was ... well ... the clouds that covered the Tucson area on Friday and much of Saturday, but the Tucson Amateur Astronomy Association adjusted nicely, and what the clouds interrupted Saturday night was successfully rescheduled to Sunday evening at its nearby Chiricahua Astronomy Complex, and the viewing was perfect! By the way, it should come as no surprise that, given the Tucson area’s focus on astronomy, TAAA is among the largest and most vibrant astronomy clubs in the nation.

Solar viewing was provided by Stephen Ramsden and a host of volunteers, including Pamela and Randy Shivak, whose amazing

solar photos I enjoy almost daily on Facebook.

The sun teased attendees on Saturday, but was on full cloudless display Sunday and many ASAE visitors were treated to their first ever telescope views of Sol. Of course, if you’re reading this magazine, you are likely more interested in the exhibitors and vendors who represent the industry side of astronomy and there were plenty on hand.

ATT’s booth was advantageously between the Kitt Peak exhibit and Aerolite Meteorites, both of which were among the most popular exhibits in the vast hall. Whether because of the popularity of The Meteorite Men or simply on for their inherent merit, commerce in meteorites was reassuringly brisk!

Anthony Davoli and ADM accessories displayed their latest products, one of which we brought home for a future review. Marcus Ludes of APM Telescopes displayed his newest creation, an ED refractor designed with the help of the Cloudy Nights community. Meanwhile, we returned with another of Marcus’ creations for a future review as well.

Tim Puckett, of Apogee Imaging Sys-

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THE ARIZONA SCIENCE & ASTRONOMY EXPO

Image 1 - NASA provided extensive exhibits for ASAE 2012.

tems, displayed that company’s newest CCD imaging systems and, yes, we’re already in the planning stages of an article covering one of those new configurations. David and Priscilla Brotherston displayed one of their unique 7foot Astro Haven clamshell observatories in a corner of the hall that also featured The Meteorite Men’s field-equipment display.

Ted Ishikawa, of Astro Hutech, displayed that company’s extensive Borg line and provided our first in-person, hands-on experience with Sightron Japan’s new nano.tracker. Look for a feature article on that new compact tracker in a future issue of ATT. The Astro-Physics team was on hand and we were delighted for the chance to admire Marj and Roland Christen’s new 1600GTO. We also enjoyed seeing Richard Taylor, owner and inventor of the Astrotrac, who teased us with upcoming news of a new, higher-capacity tracking system.

Giovanni A. Quarra Sacco represented UnitronItalia Instruments in displaying the new Avalon Instruments M-Uno and Linear Fast Reverse mounts as well as a 10micron mount, and we are always delighted by a chance to see the latest equipment and literature displayed at Canon’s exhibits.

Celestron presented one of the largest exhibits in the hall, and Mark Kfoury of

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Chroma Technologies displayed its expanding selection of astronomical filters. Ed Thomas of Deep Space Products, whose handiwork was featured in the previous issue of ATT, exhibited his growing line of mount-improvement services and products, and Exploradome’s big 12-foot observatory was also on display.

Scott Roberts and Sheldon Faworski of Explore Scientific presented the latest in that company’s expanding astro-products offerings, including a mammoth prototype of a 3-inch, 30-mm, 120-degree über-wide eyepiece for which Explore has designed a special 3-inch to 2-inch adapter to permit use of the eyepiece with 2-inch diagonals and focusers. Having experienced the eyepiece within the confines of the exhibit hall, we can’t wait to try it under a night sky.

Finger Lakes Instrumentation presented its latest CCD systems and we were treated to an imaging session using its amazing ProLine 16803 through a Officina Stellare Veloce RH 300 while visiting the New Mexico Skies Astronomy Enclave during our return trip to Louisiana. The N.M. Skies Astro Enclave, another ASAE exhibitor, will also be featured in an upcoming issue of ATT. Among the most exciting discoveries we made at ASAE was of GEOST, a Tucson-

based enterprise founded by Dr. Anthony Gleckler in 2004. GEOST has been contracted by DARPA to develop its SpaceView program (www.spaceview network.com), which program was debuted at ASAE 2012.

SpaceView enlists the aid of amateur astronomers in tracking space debris and interested astronomers were provided their first opportunity to sign up for the program at ASAE. Gary Hand of Hands On Optics was ... well ... also “on hand” for the show (sorry), and displayed some interesting vintage equipment, as well as his Astro Telescopes line of refractors, of which the 6-inch f.5.9 Achro was featured in the cover article of the previous issue of ATT. Meanwhile, David Ho of Hotech demonstrated his popular Advanced CT Laser Collimator system for Cassagrain telescopes.

Local astro-gear heads were delighted by the chance to score Howie Glatter’s Laser tools at road-show discounts and Tom Field, better known as the creator of RSpec, manned the Imaging Source booth. Among the busiest vendors was InfiniTees, the ever-popular source of astro-wear.

We were treated to our first in-person view of two new iOptron products while at ASAE: its SkyTracker Camera Mount and a novel combination battery-pack/counterweight system that prompted as many “Why didn’t I think of that!” responses as anything else at the show.

Tucson-based Lunt Solar Systems not only displayed its extensive line of solar scopes inside the arena, but visitors were treated to actual solar views using its tools, and the Lunt team also helped staff the ASAE event. Mathis Instruments displayed one of its larger fork mount configurations carrying a Planewave CDK, while the Planewave Instruments team was stationed next door exhibiting its main CDK telescopes and components.

Meade Instruments’ extensive product lines were also on display, and Lance Frederick of Monstar Prints exhibited a variety of his large-format printing services and products.

ASAE also provided our first in-person view of the new Olivon Manufacturing astroproducts line of telescopes and related equip-

THE ARIZONA SCIENCE & ASTRONOMY EXPO ment. Olivon was represented by Greg Bragg, who we’ve known for years through Meade.

Craig Weatherwax and crew brought an impressive selection of OPT inventory to the show and visitors were, of course, thrilled with the event bargains, as were we.

Optec and Starlight Instruments were stationed side-by-side and it was refreshing to see the extent to which those two companies are cooperating in product development, borrowing from the unique strengths of both companies. Starlight demonstrated a new camera-lens motor-focus system and Optec’s control systems are being extended to a growing list of accessories.

Opticsmart demonstrated its new Halo Dob setting-circle/leveling-base system, as well as its Apertura line of Dobsonians, and Kevin Nelson of QSI displayed its latest CCD imaging cameras and accessories. Larry Fisher, of ScopeBuggy demonstrated that company’s popular telescope carts and Rob and Heather Teeter exhibited Teeter’s Telescopes custom Dobsonians and Shrouds by Heather trussDob shrouds.

Steve and Tom Bisque of Software Bisque provided our first chance to see the new Paramount ME II, and SkyShed’s original POD observatory was on display as well. We also enjoyed a demonstration of the most recent edition of SkyTools 3 from Skyhound, and got our fist look at Starizona’s new truss-tube version of its Hyperion astrograph.

Michael Hattey of Starlight Express introduced that company’s new Oculus All-Sky Camera at ASAE, as well as the new Nebulus advanced micro-radiometer Sky Scanner. We also enjoyed lengthy visits with Vic Maris of Stellarvue and learned more of the lens systems that Stellarvue is now producing in its new California-based optics facility.

Art Campi was on hand to exhibit Takahashi’s most popular products and Yuri Petrunin introduced TEC’s new 300 f/5.6 ADL, a 5-element astrograph that incorporates a 3-lens field corrector.

It’s always a treat to visit with David Nagler and his wife Sandy, and we were even able to plan a new article featuring Tele Vue’s latest refractror imaging systems. The Telescope Support Systems team was set up across the

Image 2 - From left to right, Gary Parkerson, Terry Atwood and Jody Raney in the ATT booth.

isle from us and we’ve coverage planned of its unique camera-mount system in the near future.

Brian Deis of Vixen Optics, a.k.a MrStarGuy, presented Vixens current crop of astroproducts, including the popular Polarie Star Tracker, and Farah Payan of Woodland Hills Camera & Telescopes brought a large inventory for sale at the event. We were also pleased to see that Wally Pacholka (AstroPics.com) did brisk business at his booth as well.

Obviously, there was too much new on display at ASAE for full coverage here, but ATT will detail each discovery in the news sections of this and future issues. Similarly, far more photos of the show are available in the online version of this article, detailing the dis-

plays of many of the event’s exhibitors.

ASAE 2012 was a considerable success and is destined to be repeated for years to come. The ATT booth was manned by myself and daughter, Rachel Parkerson, who served as Assistant Editor during the formative years of this magazine. We were joined at ASAE by members of our local astronomy club, Jody Raney, its current president, and Terry Atwood, the professional photographer who provided most of the images that accompany this article.

As is always the case at such events, we were delighted to have the opportunity to meet so many ATT subscribers in person, and we hope to see even more of you at ASAE 2013!

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Astronomy TECHNOLOGY TODAY

71

ASTRO TIPS tips, tricks and novel solutions

Adding a Fine-Focus Arm to Your Single-Speed Focuser

By Terry Alford Do you have trouble achieving critical focus with your single-speed focuser? Owners of fast-focal ratio telescopes with single-speed focusers usually have this problem, and there are several solutions.

One is to replace the stock focuser with a dual-speed unit. (I found one with a 10-to-1 fine focus to fit my 4-inch refractor, but it cost $150!) Another solution is to install larger-diameter focus knobs. Since I have a lathe, it would not be too hard to make my own oversized knobs, but I wanted something that gave an even greater focus control. How about an arm sticking out of the side of one of the focuser knobs? That would work.

Hmm, after studying the stock focuser, it was obvious that a permanently attached arm would be unwieldy and might actually hit the rear of the focuser body as the knob rotated.

But, maybe I could make a simple

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Astronomy TECHNOLOGY TODAY

focusing lever that could be easily attached/ detached?

The accompanying photo shows my solution. I cut a 1/2-inch slice off of a piece of thick-walled PVC pipe that had a slightly larger inner diameter than the outer diameter of the focusing knob. I drilled and tapped a 1/4x20 hole and added a 2-inch long matching nylon bolt. Now, when I get close to focus and it seems I need a little more control, I slip the PVC ring over the knob and hand tighten the screw. The ring distorts slightly and grips the knob securely. So, I now have a focusing aid that gives a 3.7-to-1 finer focus advantage over the stock focuser 3.7-to-1? How did I figure that?

Well, it is actually pretty simple math.

The circumference of a circle is measured by this formula: C = 2 x pi x r. Pi

is approximately 3.14. The radius of the original focus knob is 20 mm. So the circumference of the original knob is 3.14 + 3.14 x 20 mm: C=126mm.

When the focusing lever is added to the knob, the new radius becomes 75 mm. Plugging in this new number I get 3.14 + 3.14 x 75 mm. The new circumference is 471 mm and that is just a tad above 3.7 times the diameter of the original focuser knob. If I had wanted a 10-to-1 ratio, like the aftermarket focuser mentioned above, I would need a new radius of 200 mm, about 8 inches.

While this is certainly “doable,” I find the lever I made that gives an almost 4-to-1 ratio works very well indeed. This is an inexpensive and easy to make project for anyone that needs finer control over their focuser.

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