;+
; NAME:
;	usno_close
; PURPOSE:
;	Closes asteroid ephemeris files and frees heap memory used by ephemeris
; CATEGORY:
;	smei/gen/idl/ephem; USNO Asteroid Ephemeris
; CALLING SEQUENCE:
	PRO usno_close
; INPUTS:
;	(none)
; OUTPUTS:
;	(none
; SEE ALSO:
;	usno_init
; CALLS:
; INCLUDE:
	@compile_opt.pro		; On error, return to caller
; COMMON BLOCKS:
	common USNO_INFO, USNO_PNTR
; SIDE EFFECTS:
;	Opens an ephemeris file and defines a heap variable.
; RESTRICTIONS:
;	usno_close must be called separately to close all open asteroid
;	files and free the memory used by the heap variables.
; PROCEDURE:
; >	Common block USNO_INFO contains the pointer array USNO_PNTR.
;
; >	If a pointer in the array is a valid heap pointer, then the associated asteroid
;	has been initialized (file is open; heap variable exists).
;	After usno_close is finished all asteroid files should be close
;	and all heap memory released.
; MODIFICATION HISTORY:
;	SEP-1999, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
;		Modified from USNO AE98 C-software
;-

FOR i=0, n_elements(USNO_PNTR)-1 DO BEGIN
	IF ptr_valid(USNO_PNTR[i]) THEN BEGIN
		free_lun, (*(USNO_PNTR[i])).iU
		ptr_free, (*(USNO_PNTR[i])).jd, (*(USNO_PNTR[i])).span, (*(USNO_PNTR[i])).order
		ptr_free, USNO_PNTR[i]
	ENDIF
ENDFOR

RETURN  &  END