Planetary Astrophysics is a specialized study. It mainly deals with planets, asteroids, satellites. It is one of the newest and most rapidly growing branches of astrophysics. It will be a fun study to explore but the topics will be covered in coming months.
Galactic Astrophysics is also a new exciting frontier. Here I will include topics both related to galactic and extragalactic astrophysics. The topics in this section will be covered later.
Stellar Astrophysics is the building block for other branches because what is astronomy without STARS. The topics here will be posted weekly. So start with this only as it will cover all the basics.
Celestial Physics will cover topics that are common in both branches. The topics will cover relativity, quantum physics,etc., which form a backbone to all the studies regarding the universe.