Choose between two and six images of the Sun.
The Sun is not a solid body. It is not like the Earth, or the Moon. The Sun is an enormous mass of gas that rotates
at a different velocity depending on the latitude. This phenomenon was discovered by Christoph Scheiner in 1630,
when he noticed that the rotation period at the poles and at the equator was different.
How can we measure the differential rotation? We will track at least two sunspots and compare the result to see
if it is true or not that the sunpots close to the poles rotate slower than the sunspots close to the equator.
Let's calculate it! First of all, you have to choose 2-6 images of the Sun where you want to do the measurements,
but be careful, not every day the Sun has sunspots on its surface, and the same sunspot has to be in all the images!