C+
C NAME:
C	ThomsonUBVConst
C PURPOSE:
C	Defines apparent solar magnitudes and limb darkening
C	constants to be used for the Helios UBV system
C CALLING SEQUENCE:
	subroutine ThomsonUBVConst(LT,U,APM)
C INPUTS:
C	LT	integer		= 1,2,3 for U,B,V light, resp.
C OUTPUTS:
C	U	real		limb darkening constant
C	APM	integer		apparent magnitude of the Sun
C CALLS:
C	(none)
C RESTRICTIONS:
C	1<=LT<=3
C PROCEDURE:
C >	Parameters for LT (HOS__U,HOS__B,HOS__V) are defined in the include file
C	thomson.h. Use these rather than hardwiring the values 1,2,3.
C >	UHOS(LT) is the limb darkening coefficient for Helios photometer
C	light from the U/B/V filter (LT=1,2,3). From a graph in RAUMFAHRT-
C	FORSCHUNG by LEINERT et al. LAMBDA=3650,4300,5250 A for U,B,V light.
C	From Allen (1985), p. 171, U=0.80,0.77,0.62 by linear interpolation.
C >	APMHOS(LT) is the apparent magnitude of the Sun for U,B and V light.
C MODIFICATION HISTORY:
C	JUL-1996, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
C-
	    integer	LT
	    real	U
	    real	APM

	parameter (NT = 3)
C 					  U      B      V
	real	APMHOS(NT)		/-25.96,-26.09,-26.73/
	real	UHOS(NT)		/   .8 ,   .77,   .62/

	I   = max(1,min(NT,LT))
	U   = UHOS(I)
	APM = APMHOS(I)

	return
	end