01	Astronomy	Observations of celestial bodies, their distances and positions. Includes all observation equipment and techniques. For spectroscopic and radio observations and their related data analysis of celestial bodies and interstellar space, See 03/02, Astrophysics. For chemical aspects of celestial bodies, See 03/02, Astrophysics.
02	Astrophysics	Physical and chemical aspects of celestial bodies, their origin and evolution. Includes astronomical spectroscopy, radio astronomy, planetary atmospheres and luminosity. For earth atmosphere, See Field 04, Atmospheric Sciences.
03	Celestial	The motions of celestial bodies under the Mechanics influence of gravity; Ephemerides; Eclip.