A Different Perspective on House Cusps – For the More Advanced Student of Astrology


I was studying the interrelationships between house cusps and decided to make a little list. I figure as I study and internalize my understanding of these connections, I can become a better astrologer.

Cusps are fairly important things – they are the start of the boundaries of each house an astrology chart. You can think of them as ‘energetic gatekeepers’ that allow some energies to filter in certain ways, and channel the rest in different directions. When we say that a sign ‘rules’ the cusp, we simply mean the astrological sign that the cusp is situated in at its start.

The four house cusps that we consider the most often are the Ascendant (1st house), Nadir (4th house), Descendant (7th house) and Midheaven (10th house). We associate these houses with the signs of Aries, Cancer, Libra and Capricorn and with the energies of self, family, partner and society. Personally, I would also call it the Conscious-Ego/Sub-Conscious/Shadow/Super-Ego as represented in the birth chart.

Interestingly, the Sun is close to the Ascendant at dawn, the Midheaven at Noon, the Descendant at Dusk, and the Nadir at Midnight.

Now, everyone is born with different cusp rulers, varying by sign, degree and minute – and that is dependent on longitude, latitude and timezone as well. There’s plenty of great resources out there that tells you what each sign means if it falls on one of the four cusps listed above (google helps).

Also, not all charts have neatly divided house cusps as shown in the image – sometimes they cusps are very irregular indeed! And a totally different shape is generated by way of the aspects they form with one another.

It is important to note planets that conjunct cusps, if any, and include the cusp in your astrological calculations. If we allow ourselves to consider the Vertex and other ‘hypothetical’ points in astrological reading, there is no barrier to considering the cusp as an object in itself. Significant cusps may form key configurations that would be otherwise missing without their inclusion.

It is vital to get the correct time and location of your birth. Astrolog is a wonderful free software (the one that I use) that helps you tweak settings manually to make ultra-precise charts. Be advised of time zone differences.

For those curious as to what their cusps are and what that means for them, I would encourage you to do some online research. It’s a great resource which will may also whet your appetite for astrological self-study.


Given a geometrically regular chart like this, with equal cusp sizes, I did a little calculating and charting and came up with a list of ‘cusp relations’ as I’d term them. They give you a sense of the flow of energy that astrological charts intrinsically hold. This is more for those interested in the technical-mathematical side of things.

Be aware that when more systems integrate the 13th constellation Ophiuchus (the serpent bearer) into our understanding of astrology – all these relations collapse. But astrology is a living art – as our understanding of it evolves, so so we (and vice versa). So for now, this is true – but it won’t be as true in a few decades.

A geometrically regular chart like this has 12 Sextiles / Trines / Oppositions / Yods / Squares / Semisextiles. These make 2 Grand Sextiles, 4 Grand Trines, 3 Grand Crosses and 6 Mystic Rectangles.

12 Sextiles

1 & 3
2 & 4
3 & 5
4 & 6
5 & 7
6 & 8
7 & 9
8 & 10
9 & 11
10 & 12
11 & 1
12 & 2

2 Grand Sextiles

4 Grand Trines (12 Trines)

12 Yods, 12 Active oppositions

1*8*3, 2-8
2*9*4 3-9
3*10*5, 4-10
4*11*6, 5-11
5*12*7, 6-12
6*1*8, 7-1
7*2*9, 8-2
8*3*10, 9-3
9*4*11, 10-4
11*6*1, 12-6
12*7*2, 1-7

3 Grand Crosses, 12 squares

6 Mystic Rectangles

12 Semisextiles

Just a few details for those wanting to get a deeper feel of astrological cusps and their interconnectedness.

Blessings to everyone,
~ Bairavee Balasubramaniam, PhD

Image: Astrolog screenshot