[open source - multiplatform] Development and integration of tools and numerical algorithms into the Python scripting language.

[freeware - Linux] Command-line program to automate reduction of variable star CCD images.

Windows program which creates sundials and calendars, see the dates and names of the year's moons, and calculate Easter.

[shareware - Win95/98/NT] Deepsky 99 solves an important need for amateur and professional observers. The software allows the user to plan a productive observing session and record what was observed quickly and easily.

Astronomical observation planning, logging, reporting, and telescope control software for imagers and visual observers.

Excel spreadsheet calculates temporal variation in astronomic constants, obliquity of the ecliptic, and illumination angles at any specified latitude. You need only input a date or the latitude.

[commercial and freeware - multiplatform] Interactive Java applets display the position, daily and annual path of the sun and the moon, for any time and location.

Simon Dawes provides a collection of public domain freeware written as observing aids for the enthusiastic amateur astronomer.

[commercial - multiplatform] This CD contains three Jet Propulsion Laboratory Planetary and Lunar Ephemerides along with a toolbox of FORTRAN subroutines that allow the user to obtain the coordinates of the Sun, Moon, and nine major planets.

Offers Four By Jove, software that provides precise information on the location of the four main moons of Jupiter. Also AstroVizier, which provides a precise and detailed physical ephemeris for the major bodies of the solar system.