Problem A.1: Equatorial Coordinate System Astronomers need to identify the position of objects in the sky with very high precision. For that, it is essential to have coordinate systems that specify the position of an object at a given time. One of them is the equatorial coordinate system that is widely used in astronomy. (a) Explain how the equatorial coordinate system works. (b) What is the meaning of J2000 that often occurs together with equatorial coordinates? The object NGC 4440 is a galaxy located in the Virgo Cluster at the following equatorial coordi- nates (J2000): 12h 27m 53.6° (right ascension), 12° 17'36" (declination). The Calar Alto Observatory is located in Spain at the geographical coordinates 37.23°N and 2.55°W.

Problem A.1: Equatorial Coordinate System Astronomers need to identify the position of objects in the sky with very high precision. For that, it is essential to have coordinate systems that specify the position of an object at a given time. One of them is the equatorial coordinate system that is widely used in astronomy. (a) Explain how the equatorial coordinate system works. (b) What is the meaning of J2000 that often occurs together with equatorial coordinates? The object NGC 4440 is a galaxy located in the Virgo Cluster at the following equatorial coordi- nates (J2000): 12h 27m 53.6° (right ascension), 12° 17'36" (declination). The Calar Alto Observatory is located in Spain at the geographical coordinates 37.23°N and 2.55°W.