Math of Astrology
July 11, 2012 11:55 AM   Subscribe

Could you recommend a book or web site on the math of astrology?

I'm looking for a book or web site that explains as clearly and thoroughly as possible the steps in going from a date/time and latitude/longitude to a chart of zodiac signs, planets, and house cusps. Ideally, I'd also like to try to get a sort-of 3-D picture in my head of what's happening in terms of the movement of the stars and planets over time in this model of the cosmos. Something purely focused on math would be closest to what I'm looking for: not looking for info on astrological interpretation of resulting charts. Also, I'm not that great at math, so something not too mathematically intimidating would be good.
posted by Paquda to Grab Bag (7 answers total) 10 users marked this as a favorite
Eric Francis references the website Serennu a lot and the book on Ephemeris. He's pretty friendly and I'd encourage you to post this question on his site's blog and send them an email. His explanations are lucid and clear, as well another blog contributor's, Len Wallick.

And they all refer to for the best place for charts and calculations.

My sister is a name astrologer in her country with a syndicated column fwiw so going by what I've picked up over the years.
posted by infini at 12:09 PM on July 11, 2012

Something purely focused on math would be closest to what I'm looking for: not looking for info on astrological interpretation of resulting charts.

Step by Step guide.
posted by infini at 12:15 PM on July 11, 2012

Response by poster: Thank you, Infini. I will look through the sites you recommend.
posted by Paquda at 12:18 PM on July 11, 2012

Speaking as a professional astrologer: Of course it's helpful to know the math, but it sounds like you also want a good working knowledge of the astronomy.

This is important. In the old days, astronomers were also top-notch astrologers (Kepler, Brahe, Galileo, etc.), and I commend you for wanting to learn more. I have worked for many years to educate astrologers in astronomy, and I am always surprised by how little the average person understands basic astronomical concepts. Working through the math by itself will not help you learn the astronomy conceptually, but there are other resources that will.

Mathematical calculations:

1. You will need a scientific calculator.

2. One book on astronomical calculations that is pretty straightforward is here.
3. You will also need an ephemeris
4. And a table of houses.

For understanding the astronomical underpinnings of astrology:

I like "The Secret Language of the Stars and Planets" by Cornelius and Devereaux.
By the author of "Curious George," this basic astronomy classic.

If you have questions, feel free to MeMail me.
posted by Atrahasis at 12:30 PM on July 11, 2012 [2 favorites]

Response by poster: Atrahasis, I'll check out the book you recommend, but I'd also be interested in the the math behind the ephemerides and tables of houses: I assume one could do it all from scratch, though it'd be arduous, without these pre-calculated reference books?

As as a side question, if I wanted to be able to make sense of an ephemeris, is there a book or web site that would be a good start? I mean: understand the notation used in them.
posted by Paquda at 12:39 PM on July 11, 2012

Paquda: Most ephemerides have an introductory chapter that walks you through their notations. It will typically show the date, the planet's degree at midnight or noon of that day, and sometimes other information, such as declination. They are all organized a little differently, so learn the one you have first.

Ephemerides and tables of houses are calculated using complex math formulas that reflect the changing motion of the planets. This is done by computers today, but in the old days, the math was done by hand, based on known speeds and trajectories of the planets. NASA has some nice pages on this DIY. I hope you are not planning to try this at home.
posted by Atrahasis at 12:50 PM on July 11, 2012

The only way to learn astrology, vol 1 should teach you the symbols used for planets, signs, etc.

If you know how to interpolate, you can cover an entire bed with the handwritten calculations in long form. That is how I did my first chart as a teen. I later got a trigonometric calculator, which cut the paperwork to a page or two.

An ephemeris records planetary position once or twice a day, usually at midnight and/or noon. Typically, you have to first correct local time to UTC time, then you can interpolate the position of all the planets based on the closest times listed in the tables.

Real simplistic example: If someone is born exactly at noon and the sun was at 10 degrees Aries at midnight then at 11 degrees Aries the following midnight, the sun is at 10.5 degrees Aries in the birth chart.

I hope that is clear.
posted by Michele in California at 3:29 PM on July 11, 2012

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