How much maths is in astrophysics?Watch
Observational Astronomy, on the other hand, is less mathematical than what most consider Astrophysics in some senses (more data analysis than tensor calculus) but is just one area of Astrophysics. The core areas of Astrophysics rely on a great number of areas of Physics, and "applied" mathematics (such as fluid/continuum mechanics), and even more areas of pure mathematics (like differential geometry famously in relativity, and Lie groups in various areas).
Some courses may be less mathematical (the above parts of the pure maths may not be applicable to all courses, although there are a number of well known masters courses, including Part III Maths as above, and QFFF at Imperial, which you can pick this up in to some extent) but particularly once you get to your PhD, it will be extremely mathematical - hopefully this is in to your benefit
I love maths but also physics and I've decided to choose astrophysics, I've already sent off my UCAS and applied for astrophysics but now I've heard there's not much maths in it. I thought it had loads in it which has made me think about things since I love the maths side of physics way more than the theory side (I can't do questions where you have to explain stuff but I'm great at ones where I have to do maths to find something out). What stuff do you generally do in astrophysics as well, outside of watching a few documentaries I've never really done any before (I've still not go to the astrophysics chapter of A2 Physics).
The difference - normally when most departments offer 'astrophysics' this means that are just making some astro modules compulsory, in a lot of departments these are more observational based astrophysics topics but you will have to check with the individual departments to be sure (I think imperial and Cambridge offer the maths based stuff in their 4th year modules but they dont actually specifically offer a astrophysics degree)
For the high level theoretical stuff that will pretty much only be covered in the 4th year of a mphys degree (at best) or during the phd (if there are lectures you have to attend, normally at places that offer a postgrad masters) or a post grad masters in astrophyiscs/maths/theoretical physics (part III cambridge, imperial, durham come to mind but there are probably others too) where you get to do theoretical cosmology, string theory, advanced qft, general relativity etc etc
You are most likely going to encounter theoretical astrophysics in undergrad during a theoretical physics degree (though again you will have to check) as you cover the required maths to handle those topics where as normally there isnt enough time for a typical physics degree to do that (as you do lab as well)