Shabat times algorithm?

Does someone knows of an open source algorithm for calculating the times of Shabat candle light by a GPS location?

I've found this site: hebcal that have a rest api but it doesn't s开发者_运维问答upport a gps. they directed me here but its not very understandable.

any help will be appreciated.

Thanks.

The times to light and extinguish Shabbat candles are based on local sunset. So what you really need is a way to compute the sunset time for any location on a particular date.

As I understand it, candles are lighted 18 minutes before local sunset. So once you compute the sunset time, just subtract 18 minutes and you're there.