Cactus is a general, modular, parallel environment for solving systems of partial differential equations. The code has been developed over many years by a large international collaboration of numerical relativity and computational science research groups and can be used to provide a portable platform for solving any system of partial differential equations.
libAstronomy provides a set of astronomical routines to ease the calculation of ephemerides. It includes mathematical functions to compensate various astronomical phenomena like precession, nutation, etc. The getconstellation routine finds the constellation for a given coordinate. It also calculates the positions of the sun and moon in two different precise ways.
SetiContainer is a C++ class that allows convenient access to all the information in the state files of a SETI@home client. It periodically examines these files and updates its own data members accordingly. Other programs can use this class to extract information about the progress of the client, the found signals, or the work unit being processed. Additional functions offer more advanced info (like the amount of TeraFlops in a work unit, estimated time of completion, etc.). The SetiContainer class is based on the Qt toolkit, and extensively uses Qt's Signal/Slot technique.
x10ephem computes sunrise and sunset times. It consists of a library and an assortment of utilities. The most useful utility is x10events, which parses crontab files and updates the time fields to track sun events. Combined with an X10 interface like HEYU or X10, this allows the scheduling of lighting events to follow the changing seasons and daylight savings time automatically. This application does not depend on X10; it can be used for any crontab entry you like.
Astro::Aladin is a an object-oriented interface into the resources provided by the CDS Aladin project. The Aladin Java application is driven in script mode using an anonymous pipe, while high level access to resources is provided by the module which disguises the mechanics of the data access.