Hi Martin,

I also have an astrology software(free, Linux, Windows, MacOS), it's called Morinus:
http://pymorinus.extra.hu/

It knows Placidian(semiarc) and Regiomontan Primary Directions.

Best regards,
Robert

Thanks, Rob; I'll definitely look into it. I have been busy on other things recently, but plan to get back to the question of PD software soon. (Petr: I haven't forgotten!)

Martin Gansten wrote:Also, if anyone knows of other primary direction software than the above-mentioned, please let me know.

Urania also has wide selection of primary progressions:
Ecliptic (for Asc and MC), Hour Angle (first equatorial coords), Campanus, Regiomontanus, Placidus, Topocentric, Porphyry, Horizon, Krusinski, Koch, etc.

I call them primary progressions (not primary mundane directions) since they go basic route "as on heaven so on earth". The algorithms amployed by Leo and since then ignore own planetary movements. In these sources, as the way to quicken primary directions' computations (which could take days or weeks for Regiomontanus/Campanus, and other systems), the Placidus was used (as the only system where primary directions for the whole life can be quite precisely calculated with only one chart in few hours by hand). Out of this the 1/4 degree for 90 years for sun, or 3 degerees for 90 years for moon, were ignored. Nowadays, with the advent of computers, where calculating the whole primary progressed chart takes tiny fraction of second (less than 0,0001 sec), such approximate algorthims are no longer necessary, so I went exact route. The basic key is 1 divided by "365,2422 * 365,2422" (naibod key = 0 deg 58 ' per year). This is the same route that is also employed by SwissEphemeris' test module Ceres by Dieter Koch ( http://www.astro.com/swisseph ).

The trial version (and freeware lite) can be downloaded from:

http://www.astrologia.pl/urania-en.html