Hi Kasandra,
I'm not an expert on this topic, but I think it is very interesting because I took a lot of anthropology courses in college.
The pyramids were built primarily to be the tombs of Egyptian Pharaohs, so I don't think they were every really used to study the Sun or other objects in the sky. However, there are other archaeological sites in Egypt that may have been related to early observations of the motions of the Sun and other objects in the sky. An Egyptian "stonehenge" type structure can be found in a large basin known as Nabta Playa. The temple at Abu Simbel had a special alignment with the Sun to celebrate the birth and coronation of Rameses II. The temple of the sun god Amon-Re at Karnak also appears to have special alignments with the Sun at certain times of the year. You can read more about these site here:
Nabta Playa - http://sunearthday.nasa.g...ions/egypt_stone.htm
Abu Simbel - http://sunearthday.nasa.g...ations/abusimbel.htm
El Karnak - http://sunearthday.nasa.g...cations/elkarnak.htm
Kris