A free astrology software program with versions for Windows, DOS, Mac and Unix is Astrolog 5.40. It creates natal horoscope charts and different kinds of relationship charts. Within a chart, it shows sign wheels, house wheels, aspects, elements, midpoints and more.
Astrolog 5.40 features various influence charts, biorhythms and alternative zodiacs, such as Hindu and Vedic astrology. Astrology for Windows is a software for astrological calculations as well as interpretation reports. It shows both aspect lines and aspect patterns, and it includes solar and lunar returns.
Both programs have the heliocentric and sidereal systems available. Also, both can show transitions and progressions and save charts for review. The user can also change the preferred house system. Astrology for Windows also comes in a paid version -- called AstrolDeluxe for Windows -- with additional features.