sotonye wrote: Mon Jul 22, 2019 8:52 pm
As I understand this auxiliary angle, it's just an ecliptical square to the MC. However, my eastpoint in solar fire is 5° away from an exact square to the MC, I'm not really sure why this is or if this is some mistake? My Mercury is exactly conjunct this point but given that it's not actually square the MC I'm not sure how this planet could be considered angular
You're right in a sense and wrong in a sense.
You're right in that the ecliptical square to MC is the longitude of the astronomical eastpoint (the point due east on the horizon where the horizon, the prime vertical, and the celestial equator converge). However, outside of the Morinus house system, that's almost never
called the eastpoint.
The point
called Eastpoint has the longitude of a point that is 90° from MC
along the equator, in right ascension. (Look on the Reports page in SF and you will see that its Right Ascension is always 90° fro MC.) It has no real ecliptical value except that it is a strong
hint that there might be a planet conjunct it. A planet with the same longitude as this point
and 0°00' latitude, like Sun, will always be 90° from MC; but as most planets have
some latitude most of the time, they will be square MC in RA when they are not quite on this point.
If you want to "complete the set," you can add that, while these two points mark squares to MC in longitude and right ascension respectively, Ascendant marks the square to Midheaven in prime vertical longitude.
As a practical example for you: Your Eastpoint is 5°02' Taurus (RA 57°31'). Your Mercury at 5°18' Taurus would seem, in longitude, to be 0°16'
past EP but, since it isn't an ecliptical point, we need instead to notice that your Mercury has RA 57°18', is really 0°13'
before EP. Similarly, your Pluto at 5°02' Scorpio looks like it's
opposite to the minute (0°00') your EP, but this isn't how we calculate it. Instead, the critical matter is that your Pluto has RA 240°30' (60°30' + 180°), so it is really 2°59' from EP barely worth noting. (The important angularity for your Pluto is that it is 1°10' below Descendant.)
How not to calculate these:
5°02' Tau EP
5°02' Sco Pluto (0°00')
5°18' Tau Mercury (0°13' away)
The correct way to calculate these:
57°18' RA Mercury (0°13' away)
57°31' RA EP
60°30' RA Pluto +180° (for the opposition) (2°59' away)