CARRINGTON_ROTS(3)

NAME

     carrington_rots -- central longitude of  Sun  observed  from
     SOHO

SYNOPSIS

     #include <soi_time.h>
     #include <soi_ephem.h>

     double carrington_rots (TIME obs_time)

DESCRIPTION

     carrington_rots() returns the  whole  number  of  Carrington
     rotations  that have elapsed from Nov. 9, 1853 to the obser-
     vation time plus the fraction of  a  rotation  necessary  to
     produce the central longitude as observed from SOHO.  Unlike
     the function carrtime(), the value produced is not simply  a
     linear  function  of time, even for observation times before
     launch (and after the epochs of tabulated  SOHO  ephemeris),
     for which the Earth ephemeris is used.

FILES

     ~CM/tables/ephemeris/summary
     ~CM/lib/libastro.a

SEE ALSO

     soho_ephemeris(3), carrtime(3)

DIAGNOSTICS

     none

BUGS

     Same as for soho_ephemeris().  It is assumed that  SOHO  (or
     the  Earth)  never  gets  more than 180 heliographic degrees
     away from the mean earth, a safe assumption.

AUTHOR

     Rick Bogart

HISTORY

     1997-01-03      SOI Version 2.1