From all the team, I would like to thank you for your continued support of the magazine. We hope that you find this monthâ€™s edition packed with interesting, informative and inspiring articles. This month just gone has been packed with highs and lows for the scientific community. The congressional shutdown of the US had a massive impact on all sectors, but especially the scientific. The NASA website was shut down, and scientists sent home. The only project that was given special permission to continue working was the MAVEN project, the next probe to be sent to Mars as its launch date was looming. We have also seen a visit from the JUNO probe, as it whizzed past Earth during is gravitational assist en route to the Jupiter system, due to arrive in orbit in 2015. We also saw the penumbral lunar eclipse, which is the last eclipse of this year. The weather was pretty dire in most parts of England, so perhaps some of our international readers would be willing to submit some images if they have any. Going into the coming months, we wait for the arrival of comet ISON, speculated to be one of the best comets to pass in recent years. We keep our eyes on the sky, and await its arrival. From the editorial team, I wish you all dark nights, and clear skies. Mark Woodland FRAS The Editor
Petition for the Open University to offer MSc in Astronomy/Astrophysics With all the recent changes to higher education funding, times are pretty tough with some very uncertain futures for most upcoming science graduates, there is currently a massive ‘Postgraduate Gap’; the number of postgraduates, especially in the sciences, is dwindling with a quickly increasing average age of academics in the UK. The value of higher education is something that can be clearly visualised and seen; every science and engineering graduate brings back ~£1 million in their lifetime. The demand for such graduates is bound to increase with every decade thanks to advancements in technology, and this is where the postgraduate gap slots into the giant puzzle, there is no funding for postgraduate Master’s degree programmes unless you were enrolled on one as an undergraduate or received a bursary/scholarship. Not only is it expensive, but if you have work commitments/ family commitments/health problems, then doing one full-time becomes essentially an impossible task, that’s not even taking into account commuting/living costs if the University is not nearby. The Open University however with its years of experience in part-time distance learning might be a solution, hence why I’m petitioning the OU to construct a Master’s of Science degree scheme in Astronomy/Astrophysics, a subject that the OU also has had many years of experience lecturing and teaching. Not only that, but it has quite a few excellent tools in order to perform observations remotely from your own home! The OU’s robotic telescope, known as PIRATE (Physics Innovations Robotic Astronomical Telescope Explorer), is based in Majorca, Spain and presents an excellent remote interface for communicating with the dome, instruments and telescope itself. There is a planned robotic radio telescope being calibrated and fitted at the moment with the OU, there will even be eventual access to the public thanks to the new ‘Open Science’ programme. The OU is therefore a perfect and ideal remedy for helping to broaden access to physics and astronomy whilst solving the gap in postgraduates; the courses are cheaper, there are no additional living costs/hassle of moving away (again), latest technology, can do it in your own time (earn while you learn) and you receive plentiful amounts of support as an OU student. So if you value education and giving prosperity to the future minds of Astronomy and Physics, please support the petition for the Open University to Construct an MSc in Astronomy/Astrophysics. Lawrence Bilton
Image Source: http:// www.ashbydelazouchmuseum.or g.uk/Tudors.html
Are you in need of some Help & Advice? This month we are going to Have a look at polar aligning your telescope mount with advice from Mike Greenham
Polar Aligning an Equatorial Mount The following procedure shows the polar alignment of an NEQ6 mount. This procedure can be adapted to most equatorial mounts. Step 1 : Place the Tripod in position so that the locating lug seen in this picture is facing roughly North. If you are using your telescope in the same place every time, ie a patio, itâ€™s a good idea to mark the patio in some way so you can quickly put it back in the same position each time.
Step 2 : Level the tripod in all directions. I use a small level as this is much more accurate than the bubble levels built into mounts. Once this is done place the mount head on the tripod and tighten the bolt underneath Step 3 : Roughly set your altitude using the altitude bolts. You can find this info using your phone/ Google maps etc. I use a free app for the iPhone called Scope Help that has a few useful features .
The following steps 4, 5 and 6 only need doing the first time you set up the mount. Step 4 : Now loosen off the RA clutch and rotate the mount though 90 degrees. Place the level on the counter weight shaft and get it perfectly level before locking the clutch. Adjust the RA clock by loosening the small screws and rotating the clock ring until the arrow is pointing to 6 oâ€™clock and lock the ring in place. Now loosen the RA clutch again and rotate in RA so that the clock OAS EZINE
shows 12 o’clock. The counter weight shaft should be now facing down. Take a black permanent marker and transfer a mark onto the mount as shown in the picture on the left. This has now marked the home position in the RA. When your black mark is in line with the arrow your mount is vertical. We need to do this because in further step we will be moving the RA clock. Step 5: With the RA still at 12 o’clock we will now set the declination clock. Loosen the Dec clutch and rotate until you can place the level as shown. Get this perfectly level and lock the Clutch. Now adjust the Declination clock as we did above setting it to 90 degrees. There is no need to mark anything as this clock has no need to be moved again. Now if you rotate the declination so that the clock reads 0 you mount will be exactly in its home position. Step 6: Now have a look into the polar scope. You will see something very similar to the image on the right. You can see Polaris is clearly marked as a small circle located on a large circle. Polaris isn’t actually stationary in the sky. It follows the path of the circle in the image. Loosen the RA clutch and rotate the mount in RA until Polaris is at the 6 o’clock position as shown in the image. Lock the clutch and now go back to the RA clock and set it to 0. This clock is now set and should be tightened as we won’t be moving it again. Step 7: Move the mount back to its Home position and put on your counter weights and scope and make sure everything is nicely balanced. Do this by firstly loosening the RA clutch and rotating the mount in RA. It should stay in any position you put it in. If it isn’t balanced it will swing so that either the weights go down or the scope does. Adjust the weights to obtain perfect balance. Next lock the RA in the position in the picture and then loosen the declination clutch. Now balance the scope by moving the dovetail within the mount or by sliding the telescope within the tube rings. Step 8: Ok now we are ready to turn on the mount and align with Polaris. If you haven’t got the Synscan handset then skip this step and obtain Polaris’s
position using your chosen method. Once you turn on your mount the handset will greet you with the version of software it is running before asking you to enter your location, time zone, date, time and daylight saving. Daylight Saving is British summer time so answer yes in the summer when the clocks have been moved forward.
Once we have entered all the above we will be faced with this screen. It tells us the last time Polaris transited (passed through the 6 o’clock position in our polar scope). What we do is loosen the RA clutch and rotate the mount in RA so that the RA clock shows the time shown at the top of this screen (00:24 ie 24 minutes past midnight). Lock the RA clutch and now look through the polar scope. By using only the altitude and azimuth bolts move the mount so Polaris is dead centre in its little circle. Depending on the Polaris time the small circle will be in different positions so don’t worry if it doesn’t look like my illustration. That’s it. Your mount is now Polar aligned and should track the night sky with a good degree of accuracy. After you have exited after this screen the handset will ask you if you want to begin alignment. If you answer yes it will give you the option of using 1, 2 or 3 stars. If I am imaging I normally only align on 1 star, choosing one that is near my target. If I’m just going to visually browse the sky hoping from one target to the next then I complete a 3 star alignment. I find that this then brings most objects nicely into the field of view when using the goto feature. Words & Images Mike Greenham
After writing the first article on the Royal Society, it seemed in order to do the institution complete justice another follow on was needed. As a brief recap to the first article, the Royal Society was formed one wet November day in 1660 at Gresham College, where 12 people thought it might be a good idea to form a society which specialised in Science and its development of knowledge. Christopher Wren (then 28) was giving a talk on Astronomy when the idea came about. This has never been done before, and would never be done again in this manner. The Society as the organisation become know, became the “Royal Society” after receiving its charter from King Charles II in 1662. The Royal society then went on to invent scientific publishing, peer review systematised experimentation. Brought about clarity in reporting and collated some of the best thinking minds in the world and in doing so, invented modern science. The Royal Society took an interest in all manner of things scientific from the behaviour of gases to the development of the pocket watch. Christopher Merrit invented a way of fermenting wine twice, in doing so invented champagne. John Aubrey contributed a paper on ancient stone monuments in Avebury and in doing so started the field of Archaeology. Three major things set the society apart The society was always truly international. For example German Born Henry Oldenburg became editor of the Royal Society’s first Journal (one of 7 in fact). The Philosophical Transactions It was this synergy that resulted in the Royal Society receiving offerings of papers from abroad, from Christian Huygens for example. So ideas could be exchanged globally The Society also remained neutral in all its dealings taking no political or religious bias. This fact was neatly demonstrated when Napoleon asked Humphrey Davy to attend to an issue he had in France, during the Napoleonic wars. A letter was passed to him, granting him safe passage through France. Much to the brief concern of his then apprentice Michael Faraday. This was highly unusual in those days, however the third major feature that separated the Royal Society from other institutions was that fellows did not need to be financially well off in order to be elected. Certainly it helped to be wealthy however if you were to demonstrate knowledge, skill, and ability in science this was enough to gain fellowship within the Royal Society. An example of point 3 was Leeuwenhoek had virtually no education, lived in Holland, and yet with a crude Microscope was producing some fine drawings of how the micro world appeared. Possibly being one of the first to observe bacteria. Perhaps one of the most amazing feats of the Royal Society was to elect fellows before they themOAS EZINE
selves became household names. For example Charles Darwin was elected 3 years before his trip on the Beagle, Edmund Halley was elected before he received his degree from Oxford. William Henry Fox Talbot was elected two years before he invented Photography. It is hard to write an article of this nature for an astronomy magazine keeping it on an astronomy bias, however this as I am sure you have discovered is not easy to do since the Royal Society had interests and did great things in various fields not just Astronomy. One could not discuss the Royal Society in The OAS Word without mentioning something about Isaac Newton. To give Sir Isaac Newton the treatment he deserves (though he was not a very nice man) would require another article. To delve further into the Royal Society would require a book in itself, never mind a magazine article. However it seems to be fitting to conclude by saying: The Royal Society still has as pivotal role to play today in Science. In fact as a keen scientist myself I have often thought that after winning the Nobel Prize and gaining membership to the Royal Society one has reached the pinnacle of their career. For the Society now sponsors 350 Research fellowships awards, many medals and prizes, is involved in countless debates on all manner of subjects. Supports some 3000 scientists in their work and runs the Summer Science Exhibition. References Seeing Further, By Bill Bryson, published Mixed Sources, 2010
LOOK UP! A GUIDE TO THE STARS Welcome to longer and darker nights, yes the clocks have gone back one hour (GMT). Here at OAS we have put together a small guide for cosmic bodies to view this coming month. The big event of the month and possibly this year will be Comet ISON.
THE MOON The new Moon will rise in Scorpio at 06:55 and set at 16:22 on Sunday 3rd. First quarter will be in Aquarius and will rise at 12:39 and set at 22:35 on Sunday 9th. Full moon occurs on Sunday 17th, it will rise in Taurus at 16:06 17th and will set 08:13 on Monday 18th. Last quarter will occur on Monday 25th it will rise at 23:26 in Leo and set on the 26th at 12:44 in Virgo Planets Mercury is low in the morning sky on the 13th @ 05:42 moving higher in the sky just before sunrise, caution is needed when viewing Mercury due to its position close to the Sun. Venus rises in the SE and is low to the horizon at 12.21, by 16:27 on the 5th Venus should be visible with the unaided eye however it becomes quite clear by the months end in the early evening. Mars will be observable during the early morning this month at around 01:30 on the 1st. Look out for Comet ISON near by.
Jupiter moves through our morning skies throughout the month. On the 20th at around 03:40 you will be able to see Jupiter, Moon, Orion, Sirius and Mars looking east panning round to the south. Image: Mike Greenham Saturn lies close to the sun this month as viewed from the Earth and viewing will be very difficult. Uranus for those with more powerful telescopes will be in the SW in the early hours on the 1st before moving below the horizon at approximately 04:20. On the 13th the Moon may viewing Uranus difficult after midnight. Uranus remains in the morning sky throughout November, however it will be low to the horizon by the 1st December. Neptune while faint is moving south on the 1st at 18:30, it remains in the early evening sky all month.
Comet C/2012 S1 (ISON) Credit: NASA/ESA,/J.-Y. Li (Planetary Science Institute), and the Hubble Comet ISON Imaging Science Team ISON promises to be the show stopper of the year, throughout November ISON will be seen in the early morning sky looking East.
Sky Notes by David Bood information from Stellarium software. This is a guide only. OAS EZINE
What is a black hole? Posted in Astronomy, Physics, Science, tagged Black Hole, Neutron Star, White Dwarf on 13/07/2013 | Leave a Comment »
Last weekend was a pretty big sporting weekend. Not only was there the Third and deciding test of the 2013 Lions’ tour of Australia, but there was also the men’s and women’s finals of Wimbledon, and the German Grand Prix. As far as I can tell there is no sport going on this weekend. Before someone comments below that England are playing Australia at cricket in the First Test of the Ashes, I should remind my readers (all 2 of you) that a bunch of overweight men standing around for 5 days not doing much does not constitute sport. So, with this lull in the sporting calendar, I thought I would write this post about black holes, which I have been meaning to do for a while. Nearly every one has heard of black holes, but what actually are they? And do they actually exist? Well, a black hole gets its name because it is an object from which not even light can escape. The radiation (light and other forms of electromagnetic radiation) which the central part of the black hole gives off is not able to escape the extreme gravitational field the black hole creates.
An artist’s impression of the black hole in Cygnus, with matter falling into the black hole.
Calculating the escape velocity Newton’s law of gravity allows us to calculate the force of gravitational attraction between two bodies of masses
. It is simply
Earth, which we are now going to call
. Let us suppose
face, we are going to call this second mass just
is the mass of the
is the mass of an object on the Earth’s sur. In order for the object on the Earth’s surface
19 to escape the Earthâ€™s gravitational field we have to give it a velocity. When something is moving it has kinetic energy, and that kinetic energy is given by
is the objectâ€™s velocity. The object also has gravitational potential ener-
gy, as it is in a gravitational field. The gravitational potential energy is related to the gravitational force, it is given by
Notice that the gravitational potential energy is negative, whereas the kinetic energy is always positive. The sum of the two, the total energy by
. In order for an object to escape the gravitational pull of another object, it
needs to be able to escape to infinity. If it does not escape to infinity but to a smaller distance then, technically, it has not escaped the gravitational field of the object. At infinity the PE is
as we are dividing by infinity. As the object travels further and further
away from its parent body it will slow down (as it is having to do work against the gravitational force), and so the KE will get less and less. At infinity it will be zero. So we can say that, at infinity,
is constant, so it is also going to be zero any distance from the
gravitational object, including at the surface of the planet.
Let us suppose the planet has a radius of sides can cancel giving us
, we can then write
and so, rearranging, we can write
velocity is then found by writing
. The escape
The escape velocity from Earth, a White Dwarf and a Neutron Star The equations we have just derived allows us to calculate the escape velocity from any object. We are going to calculate the value for the Earth, a white dwarf and a neutron star. The escape velocity from the Earth For the Earth, the mass is
and its radius
(note, the Earth is
not spherical, it bulges at the equator, so this is an average value). Before we plug these values of
into the equation above we need to note that the value I have quoted for the Earthâ€™s
radius is in kilometres. We cannot put it into the equation in these units, we have to convert it to metres.
, so this is the number we can plug into the equation for
we do this we get that, for the Earth, The escape velocity from a white dwarf A white dwarf is the stellar remnant of a star like the Sun. They are typically about the size of the Earth, but with about the mass of the Sun. So, for
we shall use the mass of the Sun, which
, and we shall use the radius of the Earth that we used
. These numbers give
which is 2% of the speed of light.
The escape velocity from a neutron star A neutron star is the end produce of more massive stars. The Sun is not massive enough to become a neutron star, but a star which is more than about 3 times the mass of the Sun is. In a neutron star all the space that exits in atoms is squeezed out, so it is essentially a pure lump of nuclei. A typical neutron star may have the mass of 2 Suns, but squeezed down into something the size of a city! So, for our calculation, we are going to assume a 2 solar mass neutron star,
. For the radius we will assume 10km,
. Plugging these values into the equation for the escape velocity
which is 77% of the speed of light.
The event horizon of a black hole The escape velocity from a neutron star is still below the speed of light. Pulsars are produced by radiation from the surface of a neutron star being beamed past us as the neutron star rotates. So, we have direct observational evidence that we can see radiation from neutron stars. But, in the same way that a star which is a few times the mass of the Sun will end its life as a neutron star rather than a white dwarf; an even more massive star will not end as a neutron star. This is because of something called theneutron degeneracy pressure. To put it simply, this is a physical law which says that neutrons do not all want to be in the same place. They resist this through a resistive component in the strong nuclear force. But, if a neutron star were to have more than about 3 times the mass of the Sun, the gravity is strong enough to overcome this neutron degeneracy pressure. There is no known force to stop the collapse of the neutron star, and this is what forms a black hole. We can work out the radius at which the escape velocity becomes equal to the speed of light for an e.g. 2 solar mass black hole. This is the same mass as our neutron star example above. But, as we shall see, it will need to be smaller than the 10km size of a neutron star. The radius at which the escape velocity is equal to the speed of light is what we call the event horizon of black hole. To do the calculation we just re-arrange our escape velocity equation to find
For event horizon to be
is the speed of light. The re-arrangement is that , and
we find the radius of the . Notice how close this is to the actual size of
a typical neutron star, just a little over half the size. It shows how little mass has to be added to a neutron star to tip it over the edge into becoming a black hole.
21 Notice that all of the above calculations have been done assuming Newton’s law of gravity. Newton’s law of gravity is not actually correct, it has been superseded by Einstein’s, which we call the theory of General Relativity. To do the calculations properly we should use this theory, but it is rather complicated. No, it is very complicated. But to illustrate the basic idea, Newton’s laws are fine. It is surprisingly often said that Einstein’s work led to the prediction of black holes. This is not true, they had been suggested by a geologist by the name of John Michell in 1783. But we do need Einstein’s work to do the calculations properly. Any radiation being emitted from inside of the event horizon will never get to us, the gravitational pull from the black hole stops it from escaping. How do we therefore even know that black holes exist? I will answer that question in a future blog, along with some discussion of what happens as matter crosses the event horizon of a black hole, and what might be right at the centre of a black hole.
Image of Sgtr A* the black hole at the centre of the Milkyway, as seen by the Chandra X-Ray Observatory http://en.wikipedia.org/wiki/File:Chandra_image_of_Sgr_A.jpg
Like many amateur and professional astronomers alike, I am excited about viewing comet ISON. If the hype turns out to be correct then we may be able to see this wonder with the unaided eye. Before we get into what a comet is and some details on the comet, let’s have a little look at some of the myths surrounding comets from bygone years and present day myths, and to some extent scare mongering that has popped up on the internet and mainly YouTube. Before humanities understanding of the cosmos, before our understanding of nature, humans associated things that they did not understand with the paranormal. Be it a solar eclipse, Vikings thought they had angered one of their Gods, and the God was swallowing up the sun, they would chant or scream at the sky and of course the eclipse would come to an end. Today we know what natural event causes solar and lunar eclipses. Comets were thought by some ancient cultures to be the harbingers of doom, or messengers from mythical Gods. Today we have the power of global communications, and such stories and myths pop up on places like YouTube. One such story is NASA is covering up what comet ISON really is! Believers or conspiracy theorists propagate a myth about a rogue planet that sweeps through our solar system every 3600 years called Nibiru or planet X. They believe that ISON is this planet or brown dwarf star. However all these claims are baseless and untrue, Comet ISON is just that, a comet. Comets have been dubbed ‘Dirty Snowballs’ but why? Comets are interesting celestial bodies; they originate out in the Kuiper belt and Oort cloud region. This area is the outer limits of our solar system, where it is cold. Gravity pulls together lumps of rock, dust, gases and water* to form these dark bodies. * water is frozen It is thought like asteroids, comets were formed with leftover material from when the solar system was formed. Comets are hard to detect from Earth, they are dark or have a low albedo. “Albedo- Reflection coefficient, In Latin means Whiteness or reflecting power” Comets can orbit the sun much like planets, however there orbits can be long and take many thousands of years, or once in a lifetime opportunities to view like Halley's comet. Comets can also sit out in the outer reaches and events such as a collision can send those inwards. It is only when they venture into the inner solar system that comets start to become more visible, certainly more visible to the amateur astronomer. As they move in, energy from the sun in the form of the solar winds and radiation pressure causes the volatile gases and ices to melt. The main body of the comet, the nucleOAS EZINE
us forms a thin atmosphere around it called the ‘coma’, the energy from the sun acts on the coma forming a tail. While the nucleus can be up to 60 km across the coma can be as big as the sun, and the tails can stretch for thousands of kilometres. The Coma and tail have a high albedo, the ices, gases and water are now very reflective which for astronomers is a good thing as we can now observe the comet. One thing to mention the tail points away from the heat source. Comet - Chemical Composition It is possible that comets were responsible for bringing water and life to planet earth. Astronomers and scientists now know there is plenty of water out there in the cosmos be it in a frozen state and as hard as rock. However comets are made up of frozen gases too. These gases include carbon monoxide, carbon dioxide, ammonia and methane. Other properties include compounds such as methanol, hydrogen cyanide, formaldehyde, ethanol and ethane. Comets also can contain more complex molecules such as amino acids (building blocks of life) and long chain hydrocarbons. Comet ISON (C/2012 S1) Discovery: 21st September 2012 by two Russian astronomers working for the the International Scientific Optical Network, their names are Vitali Nevski and Artyom Novichenok. Dubbed the comet of the century, ISON could be a truly spectacular comet. On the 1st October 2013 @ 17:27 UTC ISON made its closest approach to Mars, and passed within 6.74 million miles. Through October it has an average speed of 78,717 mph and will continue to accelerate until the 28th November where it will speed up around the sun to a staggering 845,000 mph. Size: Approx 3 miles in diameter, conclusion from data analyzed by NASA’s swift satellite. Viewing The comet will pass within 1.2 million miles of the suns surface on the 28 th November 2013 when it reaches perihelion. On its outward journey it will pass over the Earths northern hemisphere at a distance of 40,000,000 mile on the 26 th December. If estimates are correct you should be able to observe the comet with the unaided eye anywhere between November 28th 2013 and January 2014, depending on your location. Clear Skies! Dave Bood Sources NASA, www.cometison2103.co.uk Image by Hubble Team. OAS EZINE
Capturing the full disc of the Sun. Andy Devey This month I thought that I should cover how to capture the Sunâ€™s full disc. The Sun is a very large target and beyond the size of most CCD chips in the video cameras that are now available to the amateur astronomer. Some of my friends use the larger chips in their SLRâ€™s to capture the full disc through a telescope but these cameras have colour CCD chips and this will wash out much of the detail that is available to the monochrome CCD chip. The options available to todayâ€™s amateur solar astronomer are dependent on the personal goals that individuals set in this field. Some of my friends have opted for large frame CCD cameras such as the new DMK51 combined with a focal reducer such as a 0.5x Barlow, this will allow the user to shoot full frame video of the full solar disc. With this option every part of the Sun is shot at exactly the same time a real must with such a dynamic target in the field of view. Further the processing required to achieve the complete photo is restricted to just a few minutes. One friend uses this system to produce time-lapse full disc animations, these will show solar flares in the context of full disc and they are also very useful to capture associated shock waves [Moreton waves]. The images captured by the GONG network telescopes also capture full disc images, each image is a composite of two exposures one for the disc and another for the prominences. This is the easiest way to get full disc images but it does not deliver high-resolution full disc images. If your goal is to achieve medium resolution full disc images then you will need to take shots of the separate parts of the Sun and then merge them together in a suitable program such as Photoshop to create the full disc. Most imagers that I know will merge 4 or 9 panels to create the full disc. When tackling such a work it is essential to work fast as your target is moving [through plasma flow] and with a long delay the features will not match up across the different panels. If you have never tackled a mosaic I would recommend that you initially experiment on a static target that is about the same apparent size as the Sun, I am suggesting the Moon! If like me your goal is to achieve a very high resolution full disc, then longer focal lengths are necessary and this reduces the field of view so far more images are required to produce a full disc. The time element to process these larger images is significantly longer as I have recently found out. Making a mosaic Download the latest image from the active GONG site as this will help you rotate your camera to get the correct solar orientation before starting on your imaging run. OAS EZINE
To produce a successful mosaic it is vital to make sure that as the telescope is traversed across the face of the Sun and carefully ensure that the whole disc is covered with the photos taken. If an area is missed this is like trying completing a jigsaw only to find a piece missing! When I am making a mosaic I ensure that I have plenty of overlap with successive photos on all sides of the images. I normally start at the left side of the top of the Sun and traverse right while shooting 500 frame video sets and then move down working to the left and so on. The next stage is to process all the images to the same standard, this is fairly easy if the seeing is consistent and there are no thin cloud present but more difficult if not. I use Photoshop CS5 to construct my mosaics and I presently have no experience of other programs but there are many that are suitable. I start by opening a new document and initially select the International paper option [a large size sheet]. I then default the background colour to black using two brightness/contrast background masks and then I click on “layer” and “flatten image”. I import the first photo and set it in position, I then select and import the second photo and use the “move tool” and make it 50% transparent in “layer” this allows for fine positioning of one photo over the other [zoom in a few times to check for exact alignment]. Turn the layer back to 100% [fully on] and then select the eraser tool to merge the two together and remove any hard edges that show a clear indication that they are separate photos. Some of my friends use this process to build ¼ of the image as separate pieces and then at a later stage put the four quarters together to achieve full disc. Once the full disc is fitted together it may still look patchy with areas of dark and lighter tones. This can be smoothed out by selecting the eraser tool again at a low percentage say 2% and gently work on the darker patches to blend them lighter so that the image acquires a more even appearance. The colour layer can then be added after this stage. When I add the colour to my photos and movies I always use the colour balance mask with three separate layers for shadows, mid tones and highlight colours. I try to recreate an impression of the colours that I see in the eyepiece. The photographic equipment available and the image processing techniques are continuously changing and improving as technology advances. I personally am not expert in computing or advanced image processing techniques but I am always experimenting, willing to learn and also share my experiences and mistakes. Mistakes are a very valuable part of the learning process so just analyse what went wrong and then find the solution. The internet and particularly solar observing forums are an invaluable link to tap into the experiences of lots of expert amateur solar images and everyone is welcome to join in. I would recommend joining SolarChat and the solar section of the Cloudy nights forum. One expert solar imager Ken Crawford has posted an absolutely brilliant tutorial on solar image processing in Photoshop CS5 here is the link. I would recommend you OAS EZINE
work through this tutorial a great way to get your desired result without reinventing the wheel. Have fun with our Sun Andy Devey
Photo 1: Here is my first attempt at a high resolution solar mosaic; it comprises 40 separate photos taken at 1.6m focal length. At this stage I have merged the photos but not balanced the tones to make it look like a single image..
Photo 2 my first ever large scale mosaic attempt: a photo of the Moon in Memory of Neil Armstrong
Photo 3: Here is my first attempt at a large scale high resolution solar mosaic achieved with only very basic skill level in Photoshop CS5 usage. There is 20 hours work in this image and I shall revisit it from time to time in the future as my skill levels increase.
Not so many years ago it was a common occurrence that if you mentioned an interest in astrobiology to a gathering of scientists you’d be met with raised eyebrows, polite coughs, and sympathetic noises. The science of ‘life in the universe’ has had a rocky path to follow. There was good reason for skepticism. As much as people could agree that the fundamental questions of astrobiology were incredibly interesting – tackling such tasty morsels as life beyond the Earth, life’s origins, and the cosmic significance of life – they could also agree that meaningful answers were a long way off. A sample size of ‘one’ presents a steep challenge. Times have changed though, and perhaps the most profound shift in this scientific endeavour has come from the ‘astro’ part of astrobiology in the past couple of decades. Before the 1990’s professional astronomy had more than its fair share of planet-hunting corpses littering the landscape. As far back as in the late 1800’s, claims of planets in places like the 70 Ophiuchi system (a binary some 16.6 light years away) were quickly refuted. In the 1960’s and 1970’s claims of planets around Barnard’s Star received a confusing mixture of support and devastating criticism from different sides of the astronomical community. These efforts were pushing the boundaries of feasibility. Some relied on micrometre-level measurements of stellar motion on photographic plates, a tricky enough thing made even more so by error sources such as unreported equipment realignment and well-meant cleaning. It was not a happy situation. By the 1980’s it was only a few very dedicated, and brave, professional astronomers who carried on, developing spectroscopic techniques for sensing the Doppler shift of light from stars that might be wobbling around a common center of mass with unseen planetary companions. But believable detections of planets were thin on the ground, and it was only in the 1990’s that a quick succession of discoveries began to transform the field. First was the detection of planetary mass bodies around a pulsar, and close behind came the first truly robust evidence of a giant planet tightly orbiting a sun-like star. Flash forward nearly twenty years and we’re awash in planets. Close to a thousand confirmed worlds now adorns the public listings, and my colleagues assure me that the database of NASA’s Kepler mission almost certainly contains 3,000 more bona fide objects awaiting the seal of approval. Extrapolating the statistics tells us that there must be billions of planets roughly the size of the Earth in our galaxy that are also orbiting their parent stars at distances where a temperate surface environment could exist. In fact, some analyses posit that a ‘habitable’ world ought to exist around one of the low-mass stars within about 16 light years of us, with a ninety-five percent statistical confidence. This is one of the turning points for astrobiology, I think it could perhaps be the biggest. Now we actually know that it’s reasonable to ask questions about life on other worlds because there are other worlds in abundance, and some should be pretty close by. These provide tempting targets for the next generation of telescopic instruments, from NASA’s budget-crippling-but-amazing JWST, to the new 30-metre class observatories that are slowly moving from drawing board to mountaintops. JWST may be able to detect molecules like water and carbon dioxide in the atmosphere of a transiting Earth-sized planet around a nearby low-mass star. The great ground based observatories may complement this with an ability to spot oxygen. And all such instruments, together with observatories like the millimeter and sub-millimeter sleuthing ALMA, should reveal other properties of exoplanetary systems, such as the presence of zodiacal dust and its progenitor asteroids and comets that may provide important clues to the planetary environments.
Much closer to home, astrobiology is helping pull together disparate fields of scientific inquiry. As the Curiosity rover hauls its bulky science laboratory around the surface of Mars, it is scouring the dusty terrain at the beck and call of geologists, geochemists, planetary scientists, atmospheric chemists, and even biologists. This rover’s ground truth, and the wealth of data from other rovers and missions – from Spirit and Opportunity to the Phoenix polar lander, and great orbital craft such as the Mars Reconnaissance Orbiter and Mars Express – is creating a picture of Mars that speaks to a rich, wet, history that could have been more amenable to life. Right now there is also good evidence of seasonally varying water runoffs from subsurface ice or aquifers, and for the presence of all the base elements for life. As of yet though there is no smoking gun that points to living things on Mars; no complex organic molecules have been detected, and there are conflicting measurements of atmospheric methane, a molecule that would be a potent signal of metabolic activity. On the other hand, since the Viking missions of the 1970’s there have been no instruments on Martian soil with the specific abilities to test for the presence of live organisms or their direct fossil presence. A proposed NASA rover, Mars 2020, might change that, and might even prepare samples for eventual return to Earth.
Image: Mike Greenham
biochemistry. Also, although the modern Earth Here, on the home planet, an array of new technol- may be a poor representative for Earth’s state ogy and new thinking is being brought to bear on throughout its 4.5 billion year history, we’re getscientific questions that reach out to some central ting pretty good at unraveling the paleontological and profound aspects of the search for life. What and geophysical clues to its past, and the relationare life’s origins? How does life take over a plan- ship to life’s remarkable pathway. et? How does complex life arise? How does the human microbiome influence our evolution, and But I think, again, that the most profound shift has how does the planet-wide microbiome influence come from, and will continue to come from, our our entire environment? newly found knowledge of worlds around other suns. To put it quite simply; here finally is the opThese are tough topics, but our increasingly good portunity to expand our sample size beyond a sinability to manipulate the microscopic world of at- gle planet, and beyond a single planetary system. oms and molecules, and our still growing computational capacity is making inroads. We’ve made That is a huge leap, which is already influencing the first ‘artificial’ life (or at least cobbled together our thinking. Papers are now written that compare a franken-organism of sorts), and chemists are our circumstances to those of other worlds, and studying an array of possible routes that lead from unlike such efforts in the past, we actually have simple molecules to the emergent complexity of real data to go on. For example, a few months ago
the first simultaneous spectra were obtained of four planets orbiting the young star HR8799, one hundred and twenty-nine light years from us. These are giant worlds, not yet the terrestrial-analogs we hope for, but they present a truly alien picture that may be a portent of what is to come. Spread across this system from about 14 astronomical units from their star to 68 (a distance equivalent to the very outer limits of our Kuiper belt) they look like almost nothing we’ve seen before. Each has a unique spectral fingerprint, compounds like methane, acetylene, and carbon dioxide swirling in their atmospheres. Only one of these planetary spectra bears a slight resemblance to that from the night side of Saturn, all the others have no solar system equivalent. Glimpses like this are telling us that it’s a brave new galaxy out there; and despite the inertia of science funding, and illconceived political priorities across much of the world, very real progress is being made. In fact, I think it’s fair to say that astrobiology is starting to earn some long hoped for respect, and that’s a good thing, because who hasn’t asked the very same questions when gazing up at a night sky full of other suns? Caleb Scharf Director of Astrobiology, Columbia University, New York. Author of the best selling book “Gravity’s Engines” and his new book “ The Copernicus Complex” out Autumn 2014.
Image from: http://phl.upr.edu/press-releases/fivepotentialhabitableexoplanetsnow
What Is Lurking Around The Plough? Some of you may have a telescope . Some may have a set of binoculars sitting in a draw which need a dusting off, or you may just wonder in awe at the delights of a clear night sky. It is easy to become overwhelmed with the millions of stars overhead, you may find it difficult to find an object in the sky. So to give you your bearings starting this month we are going to have a look at
constellations to get your bearings. However to make it easier we are going to take part of a constellation which is easy to identify and find. This is called an â€˜asterismâ€™. This means a small formation of stars which is recognisable, but is part of a larger constellation. The image below left shows the constellation Ursa Major or the Great Bear.
The Plough which is part of Ursa Majo is part of the night sky which most people find easy to find and pick out. Finding the plough helps you find you
bearings and you coordinates. The plough shape is quite distinctive in the sky and once found you can find North or the pole star Polaris. Ursa Major is a constellation which is in the night sky all year round. It appears to rotate around the Pole Star Polaris. Generally speaking the Plough is in a northerly direction. At this stage will imagine you are standing in a circle and you are standing in the centre. We can divide the circle into two halves, one we will call North and the other South. The image to the left is an illustration, be it a simple one of finding north. Finding North and the North Star (Polar Star, Polaris) is how we polar align our telescopes. This is really a brief and simple way of finding North and from here you can find
other objects in the night sky. However these days many of you have smartphones, tablets, laptops etc. So downloading software such a Stellarium will help you navigate around the
sky. ( http://www.stellarium.org/ ) The image to the right is an image taken using the Stellarium software. If you have a telescope or binoculars then there are some interesting objects to find and look at. The Plough is in my opinion an area of the sky which many overlook, however with a little patients you too can view the wonders of this region of the sky. What to See! Here are some objects
Planetary Nebula: M97 Owl nebula Galaxies: M51 (Whirlpool), M81,M82,M101,M108,M109 Double Star M40 Meteor Showers: Alpha Ursa Majorides, Ursiden, Leoniderâ€”Ursiden Multiple Stars: Mizor and Alcor Words: Dave Bood
Mike Greenham OAS EZINE
Coming in the next edition of the OASCast, Alastair Leith discusses the role of Social media and the internet in astronomy. How it made communication and networking easier than back in the day where people relied on snail mail and conferences mainly to keep up to date. He also takes the opportunity to look at how online astronomy societies have evolved over the years and the tools they use to collaborate, integrate and keep in touch
Comet ISON, Royal Society Part 2, Equatorial Mounts Errate, the article on Black Holes was kindly provided by Professor Rhodri Evans of Uni...
Published on Oct 31, 2013
Comet ISON, Royal Society Part 2, Equatorial Mounts Errate, the article on Black Holes was kindly provided by Professor Rhodri Evans of Uni...