define	SECPERDAY	86400.D0	# number of sec in a day
define	MINPERDAY	1440.D0		# number of min in a day
define	HRPERDAY	24.D0		# number of hours in a day
define	DAYPERYR  	365.24219879D0	# days / tropical yr

define	LYPERPC		3.261633D0	# light years per parsec
define	KMPERPC		3.085678D13	# kilometers per parsec
define	AUPERPC		206264.8062470964D0	# how many AU in one parsec
define	KMPERAU		KMPERPC/AUPERPC
define	CLIGHT 		499.00479D0	# light travel time (in sec) of 1 AU