Cerridwen provides geocentric planetary data suitable for a broad spectrum of astronomical and astrological applications, with a focus on our solar system. Among its data you will find, for example, the time of the next sunrise or that of the last full moon, or simply the current tropical position of the sun. It comes with a simple command-line utility and a JSON server, but is also designed to serve as a basis for your own application.
AstroStack is an easy-to-use astronomical imaging and processing tool geared towards the use of inexpensive webcam CCDs. It provides a very tunable environment to produce the best quality images. It supports the following features: tunable webcam sampling; image stacking (averaging, additive etc.); pre and post-capture gamma (brightness) and contrast correction; dark-shot CCD calibration (subtractive); and an internal 16-bit grey-scale format for optimal resolution.
WCSLIB is a C library, supplied with a full set of Fortran wrappers, which implements the "World Coordinate System" (WCS) standard in FITS (Flexible Image Transport System). It also includes a PGPLOT-based routine, PGSBOX, for drawing general curvilinear coordinate graticules, and a number of utility programs. The FITS "World Coordinate System" (WCS) convention defines keywords and usage which provide descriptions of astronomical coordinate systems in a FITS image header.
GRALE is a set of tools - a library and a number of accompanying applications - to study gravitational lenses. Gravitational lenses are astronomical objects so massive that their gravitational pull even deflects light rays. This can cause multiple copies of the same background object to be visible, like a cosmic mirage. The locations and shapes of these copies can provide information about the mass distribution of the gravitational lens, which GRALE can help recover using a genetic algorithm-based method. Apart from these so-called lens inversions, it's also possible to simulate gravitational lenses.
The satpass script provides satellite visibility predictions, given the position of the observer and the NORAD element sets for the desired satellites. It can acquire the NORAD element sets directly from any site supported by Astro::SpaceTrack. It can acquire the observer's latitude and longitude from http://geocoder.us/, look up star positions in the SIMBAD catalog, and more.
ChiantiPy is a Python interface to the CHIANTI atomic database for astrophysical spectroscopy. The CHIANTI atomic database for astrophysical spectroscopy provides the information necessary to calculate the emission spectrum from hot plasmas. ChiantiPy provides several top-level classes to access the database and calculate continuum and emission line intensities.
Aciqra is a night sky simulator to show the sky and celestial objects. It uses the highly precise Aloac program to calculate highly accurate positions for planets, stars, comets, and everything else in the sky for thousands of years into the future. It can load a variety of catalogs and even custom ones with a bit of extension.