C+
C NAME:
C	HLngEarth
C PURPOSE:
C	Returns the heliographic or ecliptic longitude (in degrees) of the
C	sub-Earth point
C CATEGORY:
C	Celestial mechanics
C CALLING SEQUENCE:
	double precision function HLngEarth(tt)
C INPUTS:
C	tt(2)		integer			2-element standard time
C OUTPUTS:
C	HLngEarth	double precision	heliographic longitude (degrees, in [0,360)
C CALLS:
C	Time2SunNewcomb, Time2EclipticHeliographic
C SEE ALSO:
C	XMAP_SC_POS
C PROCEDURE:
C	Typically used as external function to e.g. href=XMAP_SC_POS
C MODIFICATION HISTORY:
C	JAN-1991, Paul Hick (UCSD/CASS)
C	JUL-1993, Paul Hick (UCSD/CASS; pphick@ucsd.edu), added option to return ecliptic longitude
C-
	    integer		tt(2)

	double precision	lat
	double precision	dis

	call Time2SunNewcomb(0,tt,HLngEarth,lat,dis)
	HLngEarth = dmod(HLngEarth+180.0d0,360.0d0)
	call Time2EclipticHeliographic(0,tt,HLngEarth,lat)

	return
	end