toddcarnes/novas

This is my copy of the US Naval Observatory's NOVAS-C software (https://aa.usno.navy.mil/software/novasc_intro) with a couple bug fixes applied. I've also enhanced it with the ability to open many more versions of the JPL ephemerides. Please give the USNO proper credit if you use this software.

novas's Issues

Add Support for DE440 and DE441

JPL has released two new ephemerides, DE440 and DE441. Support needs to be added for them.

ephem_close does not reset the EPHFILE pointer

The check to see if an ephemeris file is already open will always be true if an ephemeris file was open at any point in the program, even if ephem_close was called. ephem_close does not reset the EPHFILE pointer to NULL. This bug will be addressed during the next overhaul of the ephemeris-access software.

Memory errors occur when a call to ephem_close occurs between two calls to ephem_open. The second time ephem_open is called, if (EPHFILE) is TRUE because EPHFILE is still the address that was assigned the first time.

Two calls to ephem_open without an intervening call to ephem_close will work because the EPHFILE still is open when if (EPHFILE) checks during the second ephem_open call.

Users who open multiple ephemeris files within a particular program may wish to edit the ephem_close function as follows:

if (EPHFILE) 
{ 
  error = (short int) fclose (EPHFILE); 
  EPHFILE = NULL; // new line, reset pointer 
  free (BUFFER); 
} 
return error;

Add Access to Newer JPL Ephemerides

Original Naval observatory code only allows you to access ephemerides DE200, DE403, DE404, DE405, DE406 & DE 421. Access to newer versions of the JPL ephemerides needs to be added.

sidereal_time units bug

When NOVAS C 3.1 computes Greenwich Mean Sidereal Time (GMST; gst_type = 0) using the method based on the Celestial Intermediate Origin (CIO; method = 0), the units for the equation of the equinox are calculated incorrectly.

In sidereal_time, the line

ha_eq -= (eqeq / 240.0);

should read

ha_eq -= (eqeq / 3600.0);

since the eqeq variable has been previously converted to arcseconds instead of seconds in time.