CFITSIO is a library of C and Fortran subroutines for reading and writing data files in the FITS (Flexible Image Transport System) data format. It simplifies the task of writing software that deals with FITS files by providing an easy to use set of high-level routines that insulate the programmer from the internal complexities of the FITS file format.
Gregorian calendar 1582 is a small Python script to generate calendars for any year in the history greater or equal to one. The output format is the same as the Unix "cal" command. However, it supposes the Gregorian Reformation took place on October 4th, 1582, in contrast to the cal, which supposes the reformation took place on September 3rd, 1752.
The Virtual Observatory Quantity Data Model (VOQDM) package is a "thing"-based data model for use with scientific and mathematical data in the International Virtual Observatory (IVO). It is built upon the QML (Quantity Model Language) package and, in general terms, enables fast, convenient serialization/deserialization/manipulation of Quantity-based objects and documents. An important specific application for this package is to enable the I/O of VO-catalog-based data.
SkyDome is a tool to demonstrate the location of stars, planets, constellations, and the Milky Way during Earth's rotation. Besides the optical view, various other star maps are incorporated from satellites like COBE, EGRET, and IUE, making the multi-wavelength Milky Way visible to the user.
UFOClock draws an astronomical clock. From it you can read the time of day, phase of the lunar month, ratio of day to night, time until a solstice or equinox, and time until the end or beginning of twilight. The time of day depends on your location on the surface of the Earth, which you can enter on the command line or in a dotfile in your home directory. Location can be given as latitude/longitude or ZIP code. It is called UFO clock because it sort of looks like crop circles. It is based on Sundial by George Williams. It requires GLUT installed to run and the NOVAS library to build.
Open Source Astronomy is a comprehensive collection of astronomy software packages built for Linux, Mac OS X, and Windows. Each collection comprises approximately 5GB of software. An installation assistant is included along with a browsable documentation library covering all included packages.