Astronomical Coordinate System

ASTRONOMICAL COORDINATE SYSTEM

BY,

ISHAN K PATEL

B.TECH-AEROSPACE ENG./5TH SEM

THE ULTIMATE GOAL

• Position of the Objects

• Relative Motion

• Dimensions and Characteristics

TERRESTRIAL COORDINATE SYSTEM

THE CELESTIAL SPHERE

THE EQUATORIAL COORDINATE SYSTEM

THE HORIZON SYSTEM

TRANSFORMATION FROM HORIZONTAL SYSTEM TO

EQUATORIAL SYSTEMMeasured observed coordinates in the horizontal system, azimuth A and altitude a, can be transformed to (co-rotating) equatorial ones, hour angle HA and declination Dec, for an observer at geographical latitude B, by the transformation formulae:

cos Dec * sin HA = cos a * sin A sin Dec = sin B * sin a + cos B * cos a * cos A

cos Dec * cos HA = cos B * sin a + sin B * cos a * cos A

EFFECT OF EARTH’S ROTATION

• Objects seem to rotate around the celestial poles

• Move along the circle of constant declination

• Culmination of Circumpolar objects

QUESTIONS!