Sorry to disappoint, but I’ve never read Homestuck or any related media. I only learned that it existed a couple years ago, and it genuinely felt like the phenomenon materialized out of thin air because I’d never heard of anything like it. Like I considered myself knowledgeable about the internet until I learned that this big thing existed without my knowledge.

OK, so a real chart is this. It shows the position of the celestial objects on the sky at a particular moment, as well as the the rotation of Earth. The arrow to the left marked AC is the ascendant - this is the eastern horizon, meaning that if the sun in nearby, the time described was in the morning. This is why you need to fill out your time and location of birth.

If you think about the astrological signs as just arbitrary regions of space named by convention, this whole thing is basically just encoding of astronomical information and if you know how to read it, you can figure out various thing. For example the chart I linked has the sun at the top, so it was daytime, and the moon is on the opposite side, so it was the full moon (or close to it). You may also notice that mercury and venus are both not too far from the sun, which makes sense - the Earth never get between those and the sun, so they’ll never be on the opposite side of the sky.

Now, astology is a way to give all this pseudo-random information some meaning. There’s a whole bunch of planets which are tied to various ideas through tradition and mythology. There are “houses”, 12 subdivisions starting in the ascendant, which each have their own realm of influence and there are “aspects”. If two objects are next to each other, it’s a conjuntion and they empower each other. Opposite to each other and they are in conflict. Then you have all kinds of angles like trines, quintiles etc…

The point is that this whole thing is crammed with meaning you can explore and as you decipher the relationships of different planets and houses and their aspects (which could be anything and, in fact, typically do include everything you could think of since there’s so many of them), your mind is free to do pattern recognition (something our brains are excellent at, even if there are no actual patterns) and in the process your subconsciousness, which has already analysed the person or situation you’re trying to divine, is able to influence which patterns to elevate above others and which to miss.

The whole point of reading a chart (and, in fact, all divination) is that you already know the answer, it’s just locked up in your subconscious mind and through confirmation bias this answer will come out as you sort out the chart. It’s an excellent tool for introspection, and if you have the knack for it, you can use to give answers to other people too. It’s a tool to suspend your rationality and dig out the gut feeling. How good you are in divination then depends on how correct this gut feeling tends to be and how good you’re at reading other people (even if you don’t realise).

In the end you just look at the chart (or tarot or…) and just see one thing that is obvious. There’s no mistaking it. This is the way it is. But objectively any given divination has a million interpretation, you just pick the one that feels correct.

Of course, when talking about astrology, most people think of those blurbs in the newspapers that tell you what will happen on a given day to you and everbody born in the same sign. That’s just bullshit, an introspective tool distilled into bogus mass-consumable trash.

Edit: Forgot about the most useful aspect of astrology - it gives you an easy way to roughly remember upcoming birthdays.

I think your birth sign is whatever constellation was hiding behind the sun when you were born, and not any of the constellations that people could actually see. I guess the constellation’s juju gets amplified by passing through the sun or some shit, making them solely responsible for every personality trait you have.

i’m touching a horoscope right now

Get outta my quadrant

Vriska did nothing wrong! (I don’t do who that is I am just easily persuaded)

You know, except for all the shit she did wrong