Astrophysics and astronomy are both sciences that study the universe and its phenomena, but they have different approaches and focuses. Astronomy is the observation and measurement of celestial objects and events, such as planets, stars, galaxies, comets, supernovae, and more.

Astrophysics is the application of physics and mathematics to explain how astronomical objects and events work, such as their formation, evolution, structure, composition, energy, etc.

Astronomy is like the "what" of the cosmos, and astrophysics is like the "how."

For example, an astronomer might use a telescope to discover a new exoplanet and measure its size, orbit, and brightness. An astrophysicist might use a computer model to simulate the planet’s atmosphere, climate, and habitability.

Both fields are closely related and often overlap, as astronomers use physics to interpret their observations and astrophysicists use observations to test their theories. Many scientists identify themselves as both astronomers and astrophysicists, or simply use the term “astronomy” to encompass both aspects of the discipline. However, some may specialize in one or the other depending on their interests and skills.

Hope that this subreddit is helpful to those wanting specifically to discuss astrophysics!