The Chameleon Problem Solving Environment is based on the CPACS data format and allows third party application coupling for multidisciplinary simulation. It comprises a set of libraries and integration components for the commercial integration environment ModelCenter or the open source alternative RCE (http://www.rcenvironment.de/). It was initially developed from the German Aerospace Center (DLR).
Sunrise Sunset is a Python package that can determine the sunrise and sunset based on a given altitude zenith. It has two public methods. The first returns the sunrise and sunset in a tuple. The second returns True or False depending on whether the supplied date/time is during the night or day. The constructor takes three arguments, a date, latitude, and longitude. There is one keyword argument for changing the default zenith, which is set to "official". The zeniths are "official", "civil", "nautical", "amateur" (astronomical), and "astronomical". It does not rely on third party packages, but you may need something like pytz to create dates with timezone info.