It is remarkable what you can learn from sunrises and sunsets if you keep your wits about you.
First, I will show you how I measured the length of a day on Mars. My webcam, 8-in. f/6 telescope, and a 4× Barlow lens that turned out to be 3.4×, were quite good enough to tackle this problem close to the 2007 opposition.
Then I will take you in search of the Sun. Except at total solar eclipses, once the Sun rises, it very quickly dawns on you that you cannot see where the Sun is relative to the stars, so you have to use indirect methods. I had not planned to use the method I did. In fact, I was a bit slow to realize that you need to know where the Sun is to work out the orbits of superior planets.
You have to track the motion of the superior planets relative to the stars for a period of time, and do some calculations. You sure as heck cannot do this without making some decisions about how you describe the positions of the stars. The middle part of this chapter gives an account of the...