posted April 22, 2018 09:06 PM            

This concept has mostly only been discussed in horary charts, but I wonder if it has any effect on the natal chart.

posted April 23, 2018 03:08 PM            

Add 24° to compensate for current precession and go back to tropical zodiac. So Nirayana 3° Taurus is now located at 27° Taurus tropical. Nirayana 10° Aries is now at 4° Taurus tropical. So that knocks Libra out of the zone, leaving just tropical Scorpio IF this concept is considered at all. I don't use it.

The notion of these positions of 'via combust' was based on it being at zenith from the points of greatest exaltation for the luminaries. That serves as only as a starting point from which the strength of the luminaries can be calculated (as in traditional Indian astrology as inherited from Persia). I don't see the point of using this concept by itself. As a stand-alone it has no value. What matters more is the overall strength of the luminaries, which can be rated according to the composite measure of all the other strength ratings (Shadbala).

A person could have Moon or Sun in this zone of the zodiac, yet due to aspects and other factors both could still be quite strong.

So, I guess I'm saying there's not really a good answer to your question as to what is the difference between luminaries considered 'via combust' and just considering it by sign, etc, without that concept. The concept is outmoded by precession, superstitiously framed, and probably incomplete since it may have been inherited from another system anyway, but not fully applied.