ZET is described as 'powerful astrology program for the professional astrologer, an effective resource for astronomy students, and a wonderful training tool for beginners'. There are more than 25 alternatives to ZET for a variety of platforms, including Windows, Android, Mac, Linux and iPad. The best alternative is Maitreya, which is both free and Open Source. Other great apps like ZET are Aura Astrology (Paid), Jagannatha Hora (Free), AstroWin (Free) and Kairon (Paid).
Maitreya is a software for Vedic and western astrology. First goal is to serve as tool. The software has a lot of standard features for the daily work of western and Vedic astrologers. So it can save their time and energy; they can concentrate on the work of interpretation.
Jagannatha Hora is a Vedic astrology software. In terms of the range of calculations available, technical depth and breadth, level of customizability of calculations and ease of use, Jagannatha Hora is unsurpassed by any contemporary Vedic astrology software package.
Morinus is an easy to use astrology software under GPLv3 license. It uses the swiss ephemeris so it's very accurate (5000BC - 5000AD). It runs on every Operating System where Python and wxPython are available(Linux, Unix, Windows, MacOS).
Solar Fire Gold is an exciting culmination of years of hard work and creativity. This astrology program for Windows was first produced in 1992 and has been expanding ever since to become a world leader.