After geometry and algebra comes trigonometry, especially spherical trigonometry, because of its use in dealing with how we describe the location of objects in the sky, and how to relate positions in one coordinate system to positions in another.

What kind of math do astrophysicists use?

This usually includes 2-3 semesters of calculus, differential equations, linear algebra, advanced calculus, etc. And depending on the college, they may have one or two astronomy classes available such as intro. to astronomy and observational astronomy.

Is astronomy math hard?

Astronomy 101 is usually hard because it requires a general understanding of physics and math, which liberal arts students in particular don't always have. ... If you're a straight-A math and physics student, basic astronomy won't be too tough.