;	(25-jan-91)
FUNCTION SUN_R,DAY79
;+
; NAME:
;	SUN_R
;	
; PURPOSE:
;	Calculate the solar radius in arc seconds measured outside
;	earth's atmosphere for the date specified by D79
;
; CALLING SEQUENCE:
;	R = SUN_R(DAY79)
;
; INPUT:
;	DAY79 = Decimal days since 1 January, 1979
;
; OUTPUT:
;	R = Solar radius in arc seconds measured outside earth's
;	    atmosphere
;
; MODIFICATION HISTORY:
;	Version 1.0 - Jan, 1991, Written, G. L. Slater, LPARL
;
; NOTES:
;	See PB0R.PRO for more information on this calculation.
;-

dont_use_this, 'GET_RB0P', 'SUN_R', 'Sample calling sequence: r = get_rb0p(times, /radius)'

  a0 = 0.01720197d*(day79-3.5)
  return, 959.874d + 16.044d*cos(a0 + 0.033685d*sin(a0))
  end