Equinox

Because precession is a large effect, we must know the equinox to which these coordinates refer. Although this is usually a constant for a whole table, and so might be stored in a descriptor, observers may want to use lists of program stars compiled from heterogeneous sources. Therefore, the year of the equinox must be stored in a separate column of Real*4 values, with the label EQUINOX. This column is easily created for a star catalog with a single equinox date using the COMPUTE/TABLE tablename :EQUINOX = year command. A format of F7.1 is satisfactory.

 

Column Label Contents Units Variable Type Format Req'd?

OBJECT Object name C*32 string A32 Y

RA Right Ascension degrees R*4 real R11.6 Y

DEC Declination degrees R*4 real s12.6 Y

EQUINOX Equinox date years R*4 real F7.1 Y

MUALPHA Annual p.m. in R.A. sec/y R*4 real F7.4 N

MUDELTA Annual p.m. in Dec. arcsec/y R*4 real F7.3 N

EPOCH Position date years R*4 real F5.0 N

SPTYPE Spectral type C*15 string A14 N

MAG Approx. mag. C*11 string A11 N

COMMENT Comment C*32 string A32 N