This program parses crontab files and updates the time fields to track sun events given instructions in the comments. Combined with an X10 interface like HEYU or X10 this allows the scheduling lighting events that follow the changing seasons and DST automatically. This application does not depend on X10, it can be used for any crontab entry you like. It takes a crontab file that is assumed to contain trailing information about when the events are supposed to happen relative to sunrise and sunset events and generates a new table containing the correct times. S. Latitute is positive North of the equator.
Longitude is positive East of the prime meridian.
Timezones are positive East of UTC and should be expressed in hours for Standard Time. Do not include Daylight Savings Time offsets.