houses on birth chart

Yurikome

Hi, I tried searching for this in the archives but apparently I can't find the right keywords - I either get none results or 12 pages of them.

I was wondering why houses on your natal chart can be of different sizes? I'm a total newbie and am trying to understand my chart from astro.com. And the houses are very disproportionate. For example I've got the tiniest 6th and 12th house (even though the 12th holds my important Pluto) and vast areas of 3rd and 9th. Why is this? Is it always like this? What causes this? Is it at all important?
 

dadsnook2000

Spherical geometry

The real answer is found in understanding spherical geometry and the methods of working with the three basic coordinate systems used by scientists working with global measurements and stellar coordinates. The globe is more difficult to work with compared to a two-dimensional map.

Due to the tilt of the earths axis relative to the Sun and the Sun-Earth orbital plane, and the time of the day, and the location you are at on the globe, the MC or southern great circle may not be 90 degrees (square) to the eastern or western horizon or the Ascendant-Descendant axis. It may "lean" more towards one direction than the other. When this arc is cut into three slices to determine the houses, those arcs or segments of space will vary in size relative to those arcs or segments on the other side of the MC. This is why opposite houses have the same size or arc but not all houses have the same size or arc.

You need to find a basic book on astronomy and look at the different coordinate systems to get a visual picture of how this works. Dave
 

Yurikome

Woah, that's a higher level than I'm ready for! But thanks for the info. I sort of suspected it had something to do with this (spherical shape).

So is this at all important to my horoscope? That some houses are smaller and some are bigger, or is it "just" the result of these coordinate systems?
 

Minderwiz

The good news is that you can manager quite well with Equal Houses - that is 30 degee segments starting from the Ascendant. Indeed some of the earliest house systems that were used by the Greeks in classical times were whole sign houses starating with the sign in which your ascendanat fell.

Modern texts often dismmiss the Equal House system as something for beginners and as you get better you'll move on. However the eminent Astrologer, Rob Hand who is a leader in the research on ancient methods now uses the whole sign system for much of his work.

Even if you want to use unequal houses, as Dave and I do, you can simply rely on the Astrological software to do the calculations and not worry about the spherical geometry till you get to a point where you want to explore it. Many professional Astrologers use the computer but don't bother with the maths or theory behind the houses.

That said it's good for serious students to examine these systems. Interested amateurs can safely ignore them and still get decent results.