Gravity and Planetary Orbits should precede this lab, at least to introduce the basic physical notions behind orbits and the basis for Kepler's 3rd law. Maybe I should explain a bit. Then, applying the 1 degree per 4 minutes rule of thumb, they can get a subtended angle. This makes a great extension to the lab in semesters when Jupiter is readily visible. Otherwise, it seems to work pretty well.
Students try to understand the physical mechanisms behind several types of astronomical spectra.
This lab requires no preceding lab exercises. As it currently stands, it's quite formidable. I don't know if many'll get it without some assistance, even with the boldfacing and carefully-worded text. Help them with this concept before they are confronted face-on with it in the homeworks. The CLEA analysis package has some cool toys.