The 1.0 version of jSunTimes for Mac was available as a free download on our website. This free software for Mac OS X is a product of Jonathan Stott. The program belongs to Productivity Tools.
From the developer:
The jSunTimes package provides an API to calculate sunrise, sunset and twilight (civil, nautical and astronomical) times using Java. You are able to specify the exact latitude and longitude of the location to calculate the times for and can also specify the time zone and whether to take daylight savings time (summer time) into account.
You may want to check out more Mac applications, such as Address Book Scrubber or SimpleAlert, which might be related to jSunTimes.