Reddit mentions of An Introduction to Modern Astrophysics

An Introduction to Modern Astrophysics is an excellent and easy to read book:

https://www.amazon.com/dp/1108422160/ref=cm_sw_r_cp_apa_omrWBbDYB9MN3

It's commonly used for introductory Astrophysics courses. If you don't have a basic understanding of Calculus it won't make much sense so, if you really want to properly understand the subject, first study basic Calculus. A good introductory Calculus book would be this one:

https://www.amazon.com/dp/1285740629/ref=cm_sw_r_cp_apa_JdsWBbH1KXPAN.

You're also going to want a basic understanding of Physics so one more for that:

University Physics with Modern Physics (14th Edition)
https://www.amazon.com/dp/0321973615/ref=cm_sw_r_cp_apa_LfsWBbHJ83MT6

Those three books together should give you a basic understanding of Astrophysics and put your feet solidly on the road to further understanding. Read the Calculus book first (at least the first half of it or so) and then the Physics book. Then you'll be ready to dive into Carroll and Ostlie's book!

If you don't want to go quite that deep and you just want a really basic overview of the subject, you might consider finding Hawking's "A Briefer History of Time" or watching the PBS SpaceTime series in YouTube.

Edit: If the Calculus book is still a little unclear, your issue probably lies in Algebra. In that case, read this book before any of the others:

College Algebra (10th Edition)
https://www.amazon.com/dp/0321979478/ref=cm_sw_r_cp_apa_MqsWBbR985C30

Good luck on your journey! Give yourself at least a year or two to get through all of them and don't forget to work the problems!

Oh - download Kerbal Space Program and play it for a while. Trust me on this; you'll develop a second sense of basic orbital mechanics ;)

The Big Orange Book, an overview of astronomy from the basics of how we choose coordinates through planets, stars, galaxies, all the way to cosmology. It earned the nickname because of its common use in grad schools.

Do Americans really buy their textbooks for $500? Why does it cost so much? I just looked up a standard astrophysics textbook on amazon and it costs just below $100.