October 16, 2003

sunrise, sunset

besides being a song in fiddler on the roof, sunrise and sunset is an important part of some calendar calculations. i have been using the ICU4J astronomical calendar but once i got around to double checking the sunrise/sunset times it produced for bangkok i found it be off by almost 3 minutes, not a big deal over day for a calendar, but is kind of meaningful for other stuff like twilight calculations (and i just like to get stuff as correct as i can). so i hunted high and low and found a pretty accurate java package. btw, the majority of stuff i looked at was wrong, some of it laughably wrong (not to say my port to CF is perfect). in any case its posted to the devnet exchange where it be available eventually. the test bed is here. i guess this would be all sort of ho-hum so i spiced up the CFC a bit by including over 2,500 locations world wide. the access database accompanying the CFC contains names, locality, country longitude, latitude, and raw GMT offset. the actual timezone info (as used in java) is a bit harder to come by. the next version of this CFC should hopefully have that info plus more detailed data in the US and europe.


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