Skip Navigation Links

Ephemeris

e·phem·er·is (-f m r -s)

     n. pl. eph·e·mer·i·des (f -m r -d z)

A table giving the coordinates of a celestial body at a number of specific times during a given period.
[Late Latin eph meris, from Greek, diary, from eph meros, daily]

Pocket Stars uses data files containing ephemeris data for the sun, moon, and planets derived from the Jet Propulsion Laboratory DE405 database.  Unfortunately, these files are large so you may wish to download a smaller version containing a restricted date range. Or, you may wish to download an ephemeris with extended date ranges. This download is completely optional.

The default installation of Pocket Stars include ephemeris files covering the range of 2005 to 2015.

The ephemeris data files currently available are:

Date Range Size MB Files
2000-2010
 1.2 PocketStars.405
PocketStars.40c

2000-2020

 2.3 PocketStars.405
PocketStars.40c

1980-2040

 6.6 PocketStars.405
PocketStars.40c

1700-2200
WARNING: See note 3 below!

 54 PocketStars.405
PocketStars.40c

Instructions

Pocket Stars PDA and Pocket Stars SP

  • Exit Pocket Stars if it is currently running. (Menu.About.Exit).
  • Select an ephemeris date range from the table above.
  • Download both files to your PC (right click, then "SaveAs...").
  • Manually copy both files to your Pocket PC or Smartphone, replacing the existing files of the same name. The default installation directory for Pocket Stars PDA and Pocket Stars SPis "\Program Files\Pocket Stars\". To copy the files, use "ActiveSync.Explore".
  • Restart Pocket Stars.

Pocket Stars PC

  • Exit Pocket Stars if it is currently running. (File.Exit).
  • Select an ephemeris date range from the table above.
  • Download both files to your PC (right click, then "SaveAs...").
  • Manually copy both files to your Pocket Stars installation directory, replacing the existing file of the same name. The default installation directory for Pocket Stars PC is "\Program Files\Nomad Electronics\Pocket Stars\".
  • Restart Pocket Stars.

Notes

  1. You can verify the ephemeris date range currently installed by clicking in the lower left hand corner of the Menu.About page. This also displays diagnostic information which can be hidden by clicking the same spot again.
  2. The PocketStars.405 file contains the ephemeris for the date range. The PocketStars.40C file contains pre-calculated locations for the inner planets on each day for the date range to speed the display of orbital paths. Both files must be downloaded and copied together.
  3. The Microsoft provided calendar control used on the Sextant page and Time pages does not accept dates prior to September 1752. This marks the date when the transition was made from the Julian to the Gregorian calendar. Thus, you can only select dates after September 1752. However, it is possible to use the animation features to set the star chart to earlier dates.
  4. The same ephemeris files are used on both the PC and PDA versions of Pocket Stars.

Top support links