tyear_c

Index Page tyear_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 tyear_c ( void )
#### Abstract
       Return the number of seconds in a tropical year.
#### Required_Reading
    None.
#### Keywords
       CONSTANTS
#### Brief_I/O
       VARIABLE  I/O              DESCRIPTION
       --------  ---  --------------------------------------------------
       tyear_c       O   The number of seconds/tropical year
#### Detailed_Input
       None.
#### Detailed_Output
       The function returns the number of seconds per tropical
       year.  This value is taken from the 1992 Explanatory Supplement
       to the Astronomical Almanac.
#### Parameters
       None.
#### Exceptions
       Error free.
#### Files
       None.
#### Particulars
       The tropical year is often used as a fundamental unit
       of time when dealing with older 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 tropical centuries
       that have elapsed since the ephemeris epoch B1950 (beginning
       of the Besselian year 1950) at a particular ET epoch.  The
       following line of code will do the trick.

          century = ( et - unitim_ ( b1950_c(), "JED", "ET" ) )
                    / ( 100.0 * tyear_c() );
#### Restrictions
        None.
#### Literature_References
       Explanatory Supplement to the Astronomical Almanac.
       Page 80. University Science Books, 20 Edgehill Road,
       Mill Valley, CA 94941
#### Author_and_Institution
       W.L. Taber      (JPL)
       E.D. Wright     (JPL)
#### Version
       -CSPICE Version 1.0.0, 08-FEB-1998 (EDW)
#### Index_Entries
       Number of seconds per tropical year
#### Link to routine tyear_c source file tyear_c.c

    Thu Apr 16 08:59:25 2009