Name

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      AITOFF

Purpose

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      Convert longitude, latitude to X,Y using an AITOFF projection.

Explanation

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      This procedure can be used to create an all-sky map in Galactic
      coordinates with an equal-area Aitoff projection. Output map
      coordinates are zero longitude centered.

Calling Sequence

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      AITOFF, L, B, X, Y

Inputs

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      L - longitude - scalar or vector, in degrees
      B - latitude - same number of elements as L, in degrees

Outputs

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      X - X coordinate, same number of elements as L. X is normalized to
              be between -180 and 180
      Y - Y coordinate, same number of elements as L. Y is normalized to
              be between -90 and 90.

Notes

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      See AIPS memo No. 46, page 4, for details of the algorithm. This
      version of AITOFF assumes the projection is centered at b=0 degrees.

Revision History

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      Written W.B. Landsman STX December 1989
      Modified for Unix:
              J. Bloch LANL SST-9 5/16/91 1.1
      Converted to IDL V5.0 W. Landsman September 1997