Uploaded byRathnavel Ponnuswami
Astronomical surveying
This document provides an overview of astronomical surveying concepts. It discusses the celestial sphere model used to depict celestial objects, important astronomical terms like right ascension and declination, and the motions of celestial bodies like the Sun, stars, and planets. It also covers different coordinate systems used in astronomy like the altitude-azimuth and equatorial systems. Finally, it briefly introduces various time systems used, such as sidereal, mean, and standard times.
More Related Content
Similar to Astronomical surveying
Astronomical surveying
- 1.
- 2. SYLLABUS • Celestial Sphere •Astronomical Terms & Definitions • Motion of Suns & Stars • Celestial Co-ordinate Systems • Different Time Systems • Use of Nautical Almanac • Star Constellations
- 3.
- 4. SOME BASICS ASTRONOMY -Study of celestial/astronomic/universal objects/bodies and the phenomenon surrounding them. CELESTIAL OBJECTS Stars Planets Comets Asteroids VIRGO>LOCAL GROUP>MILKY WAY>SOLAR SYSTEM>EARTH ASTRONOMICAL SURVEY / FIELD ASTRONOMY helps in determination of latitude & longitude determination of distances for satellite communication determination of route for space ships & shuttles
- 5.
- 6. SOME BASICS CELESTIAL SPHERE& FIXED STARS
- 7.
- 8.
- 9.
- 10. CELESTIAL SPHERE FIXED STAR Theyare celestial objects that do not seem to move in relation to the other stars of the night sky CELESTIAL SPHERE To make it easier to understand the motions of objects in our skies, astronomers often depict the space as a sphere concentric to the earth, surrounding the Earth with the earth as centre and a fixed star as a point in the circumference of sphere. CELESTIAL SPHERE - DEFINITION It is defined as an imaginary sphere upon the surface of which all stars in the sky appear to be studded to an observer stationed at its centre. CELESTIAL BODY & OBSERVER
- 11.
- 12.
- 13.
- 14. T17 1. SMALL CIRCLE 2.GREAT CIRCLE 3. ZENITH 4. NADIR 5. CELESTIAL POLES 6. CELESTIAL EQUATOR 7. ECLIPTIC 8. OBLIQUITY 9. EQUINOCTICAL POINTS 10. HORIZON 11. MERIDIAN 12. VERTICAL CIRCLE 13. DECLINATION 14. RIGHT ASCENSION 15. ALTITUDE 16. AZIMUTH 17. HOUR ANGLE
- 19. MOTION OF SUNS& STARS
- 20.
- 21.
- 22.
- 23.
- 24. TRACKING THE MOVEMENTS EARTH– SUN MOON – EARTH SUN – STARS STARS – EACH OTHER
- 25.
- 26. MOVEMENT OF SUN Althoughthe stars are fixed relative to each other, the Sun moves relative to the stars. Once a year, the Sun traces out a circle on the celestial sphere called the ecliptic, which is tilted at an obliquity of 23.5° with respect to the celestial equator. The Sun crosses the celestial equator at exactly two points, called equinoxes, from the Latin for "equal nights“ The equinox where the Sun ascends from the southern to the northern hemisphere is called the spring or vernal equinox because the Sun is there on March 21. The vernal equinox is chosen to be 0 h R.A. The Sun again crosses the celestial equator halfway around, at 12 h R.A. This position is called the autumnal equinox because the Sun is there on September 23.
- 27. MOVEMENT OF SUN Thepositions where the Sun reaches its highest and lowest points are called solstices, from the Latin for "the Sun stops" as it changes direction. The Sun is highest in the sky (in the northern hemisphere) when it is at 6 h R.A. This position is called the summer solstice because the Sun is there on June 21. The Sun then has a declination of +23.5°. The Sun is lowest in the sky (in the northern hemisphere) when it is at 18 h R.A. This position is called the winter solstice because the Sun is there on December 21. The Sun then has a declination of -23.5°.
- 28. MOVEMENT OF STARS PROPERMOTION DIURNAL MOTION
- 29.
- 30. CO – ORDINATESYSTEMS 1. ALTITUDE & AZIMUTH SYSTEM (HORIZONTAL SYSTEM) 2. DECLINATION RIGHT ASCENSION SYSTEM (INDEPENDENT EQUATORIAL SYSTEM) 3. DECLINATION HOUR ANGLE SYSTEM (DEPENDENT EQUATORIAL SYSTEM)
- 31. CO – ORDINATESYSTEMS
- 32. CO – ORDINATESYSTEMS
- 33. CO – ORDINATESYSTEMS
- 34.
- 35. TIME SYSTEMS SIDEREAL TIME MEANASTRONOMICAL TIME MEAN SOLAR TIME STANDARD TIME