File: solar.el.html
See calendar.el. This file implements features that deal with times of day, sunrise/sunset, and equinoxes/solstices.
Based on the `Almanac for Computers 1984,' prepared by the Nautical
Almanac Office, United States Naval Observatory, Washington, 1984, on
`Astronomical Formulae for Calculators,' 3rd ed., by Jean Meeus,
Willmann-Bell, Inc., 1985, on `Astronomical Algorithms' by Jean Meeus,
Willmann-Bell, Inc., 1991, and on `Planetary Programs and Tables from
-4000 to +2800' by Pierre Bretagnon and Jean-Louis Simon, Willmann-Bell,
Inc., 1986.
Accuracy:
1. Sunrise/sunset times will be accurate to the minute for years
1951--2050. For other years the times will be within +/- 2 minutes.
2. Equinox/solstice times will be accurate to the minute for years
1951--2050. For other years the times will be within +/- 1 minute.
Defined variables (11)
calendar-latitude | Latitude of ‘calendar-location-name’ in degrees. |
calendar-location-name | Expression evaluating to the name of the calendar location. |
calendar-longitude | Longitude of ‘calendar-location-name’ in degrees. |
calendar-time-display-form | The pseudo-pattern that governs the way a time of day is formatted. |
solar-data-list | Data used for calculation of solar longitude. |
solar-error | Tolerance (in minutes) for sunrise/sunset calculations. |
solar-n-hemi-seasons | List of season changes for the northern hemisphere. |
solar-northern-spring-or-summer-season | Non-nil if northern spring or summer and nil otherwise. |
solar-s-hemi-seasons | List of season changes for the southern hemisphere. |
solar-seasons-data | Data for solar equinox/solstice calculations. |
solar-sidereal-time-greenwich-midnight | Sidereal time at Greenwich at midnight (Universal Time). |