Astrophilus wrote: Fri May 09, 2025 5:53 pm All ASC-based house systems encounter problems at polar latitudes once ASC turns retrograde. Also primary directions (at least Ptolemy's method of proportional semi-arcs) fail to work when applied to circumpolar degrees or objects.

That's exactly right. Horoscopic astrology stricto sensu doesn't work in circumpolar regions (this applies to Regiomontanus directions too, with their artificial horizons). Presumably the principle of As above, so below still applies, but other interpretative models than the classical ones would be called for. The groundwork needed to put that sort of project on a secure footing is daunting.

I'm sorry I missed replying to Ouranos's post earlier. I haven't studied Marr's method of directing in detail, but as far as I know, it differs from classical models in several respects. The mathematical difference is the least of these (the so-called Topocentric system is a very minor variation on Placidean directions under the pole, which in their turn are just an approximation of the semi-arc system). More importantly, I believe Marr wants direction 'hits' to correspond very closely (to the day, or within a few days) to events, which is made more likely by using a large number of significators as well as promissors, including transsaturnian planets, house cusps, and minor aspects, and directing both with and against the primary motion. In pre- and early modern astrology, directions were seen rather as giving rise to periods within which certain types of events might be expected. A single direction could thus correspond to several events, and not all events, even major ones, would necessarily have a corresponding 'hit': they could be signified, for instance, by a significator being directed through the terms of a particular planet, which would thus become a chronocrator (qāsim/divisor), and by the state of that planet both in the nativity and in the annual revolution.

As for my use of Alcabitius, it was the standard house system for most of the medieval period, and I have found it to work slightly better than Porphyry (the oldest attested quadrant system, probably dating to the first century either CE or BCE, if not earlier). I have compared it with some later, popular systems (such as Regiomontanus and Placidus), but haven't found them more convincing in practice.