How to quickly find 15-degree aspects

If your astrology software does not recognize aspects in increments of 15, do not despair!

Its simple. Just take the position of the planet/luminary and add 15° … Let’s use the chart of Louis Pasteur as an example.

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pasteur AA 2am chart

Pasteur’s Moon at 17GEM55 has been referred to as ‘unaspected’. Let’s see if there are any 15° aspects. Let’s round its figure up to 18° because it is so close. When we add 15° we get 33. Subtract 30 and that is 3° — which shows us that any 15 aspect will show up +/- 3° in any sign. (18 – 15 also = 3).

What lies 1-5°? Sun & Neptune, just short of 5° Capricorn, which is a 165° aspect (dubbed “Quindecile”).

We would use a tighter 1° orb for the 15° aspect, but an orb of 2° is certainly acceptable for obtuse angles (between 90 & 180), and I think also for the 75° & 105° aspects.

Counting in 15° increments from his Moon position, if Pasteur had anything at 1-4° Gemini or Cancer that would be an aspect of 15°.

If there were antyhing at ~18 Cancer or Taurus, of course, that would be a 30/semi-sextile.

3 Leo or Taurus = 45/semi-square.

18 Leo or Aries = 60/sextile.

3 Virgo or Aries = 75° aspect.

18 Virgo or Pisces = 90/square, of course.

3 Libra or Pisces = 105°.

18 Libra or Aquarius = 120/trine.

3 Scorpio or Aquarius = 135/sesquisquare.

18 Scorpio or Capricorn = 150/quincunx.

Now an opposition to the Moon would fall at 18 Sagittarius. Subtract 15 from that and you get 3 Saigittarius. Add 15 and you get 3 Capricorn. A 165/Qd qualifies for a 2° orb, so we look at 1-5°: Sun & Neptune are there, just short of 5°.