Helpful Videos and Apps Illustrating the Celestial Sphere

Many students are struggling with the concept of the celestial sphere right now. It is not an easy concept, but it's key for understanding how observational astronomers locate and study objects in the sky using telescopes. This topic is usually not covered in a physics-oriented astronomy course at the level of Ay16, which I think is a shame since it's so central to the enterprise of astronomy.

Make no mistake about it: this is a tough concept. We live on a moving, tilted platform, which is good for getting a view of the entire universe, but troublesome for devising an intuitive coordinate system. Yesterday in class was our first pass. We'll take more passes at it in TALC, and we'll linger on the topic Thursday. Our next lesson on telescopes and optics can wait a class session until we're comfortable with the sky.

If you're struggling with these concepts, it's okay. It really is! I struggled mightily as a graduate student at UC Berkeley 12 years ago, and I now have the benefit of tons of experience. But when the TFs and I were preparing for this lesson, we struggled again! Embrace the struggle as runners embrace the burn pushing themselves for that extra mile, or weight lifters struggle against 10 extra pounds in the bench press, or a musician struggles against playing the piece just a bit faster.

Here's a short but wonderfully clear video illustrating the Earth in relation to the celestial sphere. Watch it and watch it again. Then watch it again :)



Here's a fun simulator to help you visualize the Earth's relation to the celestial sphere, as viewed from the stars (watching the Earth rotate) and from the Earth (watching the stars rotate across the sky). I found this simulator on the Astronomy Education at the University of Nebraska-Lincoln.

Google is your friend in this class. We live in an age of a plethora of online tools to help you understand key concepts that we won't have time to cover explicitly in class. When you find something helpful, write a blog post and refer your classmates to it. Let's help each other through these tough concepts.