Eclipses, Moon Phases and Seasons
Windows software to calculate exact times of solar and lunar eclipses,
txtextension). When it is loaded into Excel (as a Text File — accept the defaults) and the column widths, etc., are adjusted, it looks like this:
IM-TS Imbolc BE-TS Beltane LU-TS Lughnasadh SA-TS Samhain SPR-EQ Spring equinox SUM-SO Summer solstice AUT-EQ Autumn equinox WIN-SO Winter solstice DM Dark Moon 1QM 1st quarter moon FM Full moon 3QM 3rd quarter moon PELE Penumbral lunar eclipse PALE Partial lunar eclipse TOLE Total lunar eclipse PASE Partial solar eclipse ANSE Annular solar eclipse TOSE Total solar eclipse
For an explanation of the concept of the chronological Julian Date, and its relation to the more well-known concept of the astronomical Julian Date, see here.
Some web pages (in particular, those of Fred Espenak) give eclipse dates using a calendar-switch-over, according to which the dates of eclipses occurring after the date of the official introduction of the Gregorian Calendar (October 15, 1582) are given in the Gregorian Calendar, and dates of eclipses occurring before this date are given in the Julian Calendar — sometimes with no indication of which calendar is being used. Thus if comparing eclipse dates given by this software with dates available on other websites one must be careful as to whether the dates given on those websites are in the Gregorian Calendar or in the Julian Calendar (and don't forget about astronomical year numbering).
This program implements the same astronomical algorithms as our earlier program Equinoxes, Solstices and Cross-Quarter Days. For the solar cross-quarter days (Imbolc, etc.) the date is calculated using the 'true sun' method (not the 'mean sun'). For an explanation of the difference between 'mean sun' and 'true sun' methods, and for comments on the solar cross-quarter days and the seasons, please see the documentation for that program here.
Our later program Celtic Festival and Cross-Quarter Dates calculates the dates of Imbolc, etc., using the definitions of the solar cross-quarter dates (using 'true sun') and the true Celtic festival dates. For further details see here.
Trial version: A copy of Eclipses, Moon Phases and Seasons is available for free download from this website for the purpose of evaluation. Click on the following link for further information:
The developer of this program, Peter Meyer, is currently available for custom software development. You can contact him here.