Need some advice!!

I just purchased a Celestron C8 on Astromart. Its the Carbon Fiber model. It arrived about a week ago. It appears to be in excellent condition - like new.

Last night was the first night I was able to use it. I found two significant problems:
(1) I could not get it to come anywhere near focus
(2) While attempting to focus the image moved all over the place.

Given that I am a complete neophyte with this type of scope I was hoping that someone could give me some advice and point me in the right direction.

Thanks for any help you may be able to provide.

Gary

Hi Gary,
I owned one of those, the NS8GPS, it was a very nice scope.
Are you using a diagonal when it does not reach focus? What eye pieces were used?
The moving of the image is due to mirror flop. The primary mirror is moved up and down to achieve focus. It slides one a tube which is lubed with grease. As it moves it can also move side to side slightly, which causes the image shift.
Try adjusting the focus all the way in and out a few times to spread the grease on the tube, this is know to help.

Attached Image:

Some mirror shift (about 45" or about the width of Jupiter is normal). As for focusing...what exactly do you mean? Wouldn't focus at all? Didn't look sharp? What were you focusing on?

You haven't added any accessories to the rear cell with screws that could be impinging on the mirror have you?