.help galsup Jun99 "Slalib Package"
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      SUBROUTINE slGASU (DL, DB, DSL, DSB)

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      G A S U
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  Transformation from IAU 1958 galactic coordinates to
  de Vaucouleurs supergalactic coordinates (double precision)

  Given:
     DL,DB       dp       galactic longitude and latitude L2,B2

  Returned:
     DSL,DSB     dp       supergalactic longitude and latitude

  (all arguments are radians)

  Called:
     slDS2C, slDMXV, slDC2S, slDA2P, slDA1P

  References:

     de Vaucouleurs, de Vaucouleurs, & Corwin, Second Reference
     Catalogue of Bright Galaxies, U. Texas, page 8.

     Systems & Applied Sciences Corp., Documentation for the
     machine-readable version of the above catalogue,
     Contract NAS 5-26490.

    (These two references give different values for the galactic
     longitude of the supergalactic origin.  Both are wrong;  the
     correct value is L2=137.37.)

  P.T.Wallace   Starlink   25 January 1999

  Copyright (C) 1999 Rutherford Appleton Laboratory
  Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.

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