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+.help calyd Jun99 "Slalib Package"
+.nf
+
+      SUBROUTINE slCAYD (IY, IM, ID, NY, ND, J)
+
+     - - - - - -
+      C A Y D
+     - - - - - -
+
+  Gregorian calendar date to year and day in year (in a Julian
+  calendar aligned to the 20th/21st century Gregorian calendar).
+
+  (Includes century default feature:  use slCLYD for years
+   before 100AD.)
+
+  Given:
+     IY,IM,ID   int    year, month, day in Gregorian calendar
+                       (year may optionally omit the century)
+  Returned:
+     NY         int    year (re-aligned Julian calendar)
+     ND         int    day in year (1 = January 1st)
+     J          int    status:
+                         0 = OK
+                         1 = bad year (before -4711)
+                         2 = bad month
+                         3 = bad day (but conversion performed)
+
+  Notes:
+
+  1  This routine exists to support the low-precision routines
+     slERTH, slMOON and slECOR.
+
+  2  Between 1900 March 1 and 2100 February 28 it returns answers
+     which are consistent with the ordinary Gregorian calendar.
+     Outside this range there will be a discrepancy which increases
+     by one day for every non-leap century year.
+
+  3  Years in the range 50-99 are interpreted as 1950-1999, and
+     years in the range 00-49 are interpreted as 2000-2049.
+
+  Called:  slCLYD
+
+  P.T.Wallace   Starlink   23 November 1994
+
+  Copyright (C) 1995 Rutherford Appleton Laboratory
+  Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.
+
+.fi
+.endhelp