jyear_c

Index Page jyear_c
A B C D E F G H I J K L M N O P Q R S T U V W X
Procedure Abstract Required_Reading Keywords Brief_I/O Detailed_Input | Detailed_Output Parameters Exceptions Files Particulars Examples | Restrictions Literature_References Author_and_Institution Version Index_Entries
#### Procedure
       SpiceDouble jyear_c ( void )
#### Abstract
       Return the number of seconds in a julian year.
#### Required_Reading
       None.
#### Keywords
       CONSTANTS
#### Brief_I/O
       VARIABLE  I/O              DESCRIPTION
       --------  ---  --------------------------------------------------
       jyear_c    O   The number of seconds/julian year
#### Detailed_Input
       None.
#### Detailed_Output
       The function returns the number of seconds per julian
       year.
#### Parameters
       None.
#### Exceptions
       Error free.
#### Files
       None.
#### Particulars
       The julian year is often used as a fundamental unit
       of time when dealing with ephemeris data.  For this
       reason its value in terms of ephemeris seconds is
       recorded in this function.
#### Examples
       Suppose you wish to compute the number of julian centuries
       that have elapsed since the ephemeris epoch J1950 (beginning
       of the julian year 1950) at a particular ET epoch.  The
       following lines of code will do the trick.

          century = ( et - unitim_c ( j1950_c(), "JED", "ET" ) );
          century = century / ( 100.0 * jyear_c() );
#### Restrictions
       None.
#### Literature_References
       Explanatory Supplement to the Astronomical Almanac.
       Page 8. University Science Books, 20 Edgehill Road,
       Mill Valley, CA 94941
#### Author_and_Institution
       E.D. Wright     (JPL)
       W.L. Taber      (JPL)
#### Version
       -CSPICE Version 1.0.0, 08-FEB-1998 (EDW)
#### Index_Entries
       Number of seconds per julian year
#### Link to routine jyear_c source file jyear_c.c

    Thu Apr 16 08:58:26 2009