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      Compute sun position from date/time and long/lat.


Calling Sequence

      sunaltazi, time, lng, lat, azi, alt


      time=t Date and time string or double in
          precision Julian Seconds.
      lng, lat = Longitude and latitude. May be arrays. in

Keyword Parameters


        ZONE=hrs Hours ahead of GMT (def=0). Ex: zone=-4 for EDT.
        SUBLNG=lng Subsolar point longitude (deg).
        SUBLAT=lat Subsolar point latitude (deg).
        /NOREFRACT Means return true altitude, not refracted.
        ERROR=err Time error flag (0=ok).


      azi, alt = corresponding solar azimuth and altitude out
          at given points. Altitude is refracted, not actual.

Common Blocks


      Note: true alt returned unrefracted if it is < -1 deg.

Modification History

      R. Sterner, 1995 Dec 13
      R. Sterner, 1998 Jan 19 --- Renamed from sunpos to avoid conflict
      with a routine of the same name in the IDLASTRO library from GSFC.
      R. Sterner, 2001 Jan 24 --- Added /NOREFRACT.
      R. Sterner, 2004 Jan 07 --- Fixed a bug for multiple times.
      R. Sterner, 2010 May 04 --- Converted arrays from () to [].
  Copyright (C) 1995, Johns Hopkins University/Applied Physics Laboratory
  This software may be used, copied, or redistributed as long as it is not
  sold and this copyright notice is reproduced on each copy made. This
  routine is provided as is without any express or implied warranties
  whatsoever. Other limitations apply as described in the file disclaimer.txt.

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