Department of Surveying Science and Geomatics, Faculty of Architecture, Planning and Surveying, University Technology MARA Arau, Perlis
At the end of the lesson, students should be able: To
explain the various defnition of astronomy and feld astronomy Able to explain the relationship between feld astronomy and land survey works. To describes terms and terminology of celestial sphere
Astronomy, derived from the Greek words for star law, is the scientic study of all objects beyond our world. It is also the process by which we seek to understand the physical laws and origins of our universe
“The scientifc study of the universe beyond the earth, especially the observation, calculation and theoretical interpretation of the positions, dimension distribution, motion composition and evaluation of celestial bodies and phenomena” – Morris 1997
“Queen� of Science Incorporate many discipline such as physics, particularly optics, mathematics and celestial mechanics.
“The science which treats of the heavenly bodies”
INVESTIGATES:
Their motions and the laws which govern them;
Their nature, dimensions, and characteristics
The infuence they exert upon each other either by their attraction, their radiation, or in any other way
The Sun provides energy to live.
The Sun and Moon cause the tides.
The Moon causes eclipses.
Earth's orbit provides our annual calendar.
The constellations are used for navigation.
Field of astronomy knowledge related to relative position of heavenly bodies.
useful for Land Surveyor in many of survey’s felds such as cadastral, Topography Survey, Geodesy, hydrographic surveying and so on…
Involved with theory and calculation of astronomy observation and solution from the observation.
Azimuth determination for cadastral surveying
To sort the cadastral work between land blocks and separated land lots
to check traverse bearing and inner angles or long distance traverse
Used in control survey for geodesy
To determine the position of geodetic and geographic points on the earth
Celestial Sphere
Celestial Equator
Horizon
Celestial Meridian
Zenith and Nadir
Prime Vertical
Celestial Pole
Altitude Azimuth
A big see-through imaginary globe around the Earth.
Earth is centered of celestial sphere
The astronomical objects (stars, moon, sun) are stuck on this sphere.
Something like a globe
Can be considered as a geometrical device to enables us to record and measured the direction of the stars
ď‚ž
Star A, B, C, D and E represent the actual position of the stars
ď‚ž
SA, SB, SC, SD and SE is imaginary position of the stars after it was projected through celestial sphere
EARTH
CELESTIAL SPHERE
Great Circle on the celestial sphere Imaginary plane “Tangent” (just touch) to the earth at your location. 90° form Zenith or Nadir Different location on the earth, different horizon plane Form through the intersection of the celestial plane and horizon plane
Z
EARTH
HORIZO N
N
• Geometrically, it is the point on the celestial sphere intersected by a line drawn from the observer's location on the Earth's surface through the center of the Earth.
ZENITH (z)
EARTH
NADIR (N)
Solar Zenith Angle
Points on the Celestial Sphere that are directly above the Earth's Poles Intersection between celestial and pole axis Celestial North Pole and a Celestial South Pole
ď‚ž
Is formed by a great circle and perpendicular to the axis pole where it coincides with the plane of the equator on the earth
A great circle that runs north – south and passes through your zenith and nadir and celestial pole
Your meridian divides your sky in half
ď‚ž
Vertical is the vertical circle passing east and west through the zenith and nadir, and intersecting the horizon in its east and west points
The “line” (really part of a great circle) that goes straight down from the star to the horizon.
Technically altitude is the angle along the vertical circle between the horizon and the star.
ď‚ž
The angle from the north point on the horizon to the foot of the vertical circle that goes through the star
W N
S AZIMUTH (A)
E
ď‚ž
The north and south points are points caused by intersection of two great circles of the celestial meridian and celestial horizontal circle.
ď‚ž
The east and west points are points caused by intersection of two great circles , prime vertical and celestial horizontal circle.
Angle measured north and south from the celestial equator
Object on the Celestial Equator has a dec of 0o
Object on the North Pole has a dec of +90o
Object on the South Pole has a dec of -90o
Lines of latitude are horizontal lines around the earth.
The equator is at latitude 0 degrees and is the longest line of latitude.
The poles are at latitude 90 degrees
The tropic of Cancer is 23.5 degrees north.
The tropic of Capricorn is 23.5 degrees south
N Pole = latitude 90 N Arctic Circle 66.5 N
Tropic of Cancer 23.5 N
Equator = latitude 0
Tropic of Capricorn 23.5 S
Antarctic Circle 66.5 S S Pole = latitude 90 S
West of Greenwich
West of Greenwich
Greenwich Meridian = 0
Lines of longitude run from pole to pole All lines of longitude are the same length They are sometimes called “great circles”. The Greenwich meridian which passes through London, UK is 0 degrees longitude. Places are either west or east of the Greenwich meridian. There are 360 degrees around the globe.