The Spin of the Earth

[Gregg1956]

When I replaced my old 50mm telescope with my new 70mm Celestron I went to the website of the store that sold them and read the comments left by people who had bought the same telescope. The vast majority gave the 'scope very high marks. (I highly recommend it.) The few who gave it a poor rating didn't know what they were doing and blamed the telescope for their own ignorance. They hadn't bothered to learn anything.

A glaring example of this is a guy who said the clamps were defective, that the telescope wouldn't stay centered on any object he viewed. He exchanged it for another telescope of the same model. The second 'scope did the same thing. 

Of course it did! No matter how much you tighten those clamps you can't stop the Earth from spinning! The telescopes weren't defective, he just didn't realize he was witnessing the spin of the Earth. The same thing will happen with every telescope (unless it has a motor drive with automatic tracking).

When you center a celestial object in your telescope's field of view it will immediately begin to slide out of view. The object isn't moving, you and your telescope are. The Earth is spinning. The higher the magnification, the faster the object will seem to move.

It's always a good idea to learn some basics before going out with your new telescope.