PRO ZENPOS, date, ra, dec, latitude=latitude, longitude=longitude, degrees = degrees
 COMMON SITE, lat, lng

 if N_params() EQ 0 then begin
     print,'Syntax - zenpos, dte, ra, dec, [latitude = , longitude =, /Degrees]'
     print,'         dte = Julian Date
     print,'         Ouput Ra, Dec in radians (unless /Degrees is set)'
     return
 endif

 ; Override common block parameters with keywords
 if N_elements(latitude) ne 0 then lat = latitude
 if N_elements(longitude) ne 0 then lng = longitude

 if N_elements(lat) eq 0 then read, $
       'Enter latitude and longitude (in degrees): ',lat,lng
;
;                            Define the needed conversion factors.
;
 d2rad = !DPI / 180.D0
 h2rad = !DPI / 12.D0
;
;                Get the sidereal time corresponding to the supplied date.
;
 ct2lst, lst, lng, tzone, date  ;tzone dummy parameter since we give Julian date
;
;                            Compute the RA and Dec.
;
 if keyword_set(degrees) then begin
    ra = lst*15
    dec = ra*0.0d + lat
 endif else begin   
    ra = lst * h2rad
    dec = ra*0.0d + lat * d2rad
 endelse
;
 RETURN
 END