Question on Celestron Ultima 8 Problem with the dr

I just purchased a very low usage Celestron Ultima 8. Its an unusal example because it was originally sold by Orion Telescopes so the tube is white not black, grey, or orange.

Anyway, this thing is huge! I told my wife "it fits in its own suitcase honey, it won't take up much room at all"....

I've assembed the telescope and am having a problem with its "Right Ascention" drive. I can't move the telescope from side to side with the hand controller. When I press the buttons to skew the scope I hear the motor working but the scope doesn't move.

The declanation motor and the motor focuser motors work as expected.

I belive this is probably why the original owner sold it to me...This was purchased at a VERY good price and the optics are flawless-the whole scope looks almost new.

I opened up the drive base and the worm gear doesn't appear to turn when the scope is skewing like it should. It almost looks like there is a belt connecting the motor to the worm gear shaft?

The electronics look ok, which is a relief because they would be hard to replace. Has anyone had a similar problem with a C-8 of that vintage? How would you remove the worm gear mechanism to check out the motor and the gearing? (I see two stainless steel screws holding the whole assemly to the base but when they are removed nothing budges).

There are two options for powering this scope, a 9V battery or a 12 V external (by using a jack) power source. Could my problem be that I am only using the 9V source?

There is only one good answer to your quandry... Ask Uncle Rod.. I am sure he will wander by here in a day or two but you could try to contact him directly.

Jon

Well I carefully removed the gearing mechanism that connects the motor to the worm. Its a flat sort of "pear shaped" gearing mechanism to connect the worm shaft to the motor. The worm gear turns easily enough it just looks like this thing NEVER had any lubrication since leaving the factory. A little 3-1 and everything seems to work.

I do have a question. What sort of movement can I expect from the hand controller? (the only other scope that I have to compare this with is a ST80 refractor) Looking at the gearing it doesn't seem like the motor is designed to really turn that scope fast. Is the hand controller only used for "fine" adjustments and you simply declutch the telescope on its mount to move it big adjustments?

Brent Campbell said:

I just purchased a very low usage Celestron Ultima 8. Its an unusal example because it was originally sold by Orion Telescopes so the tube is white not black, grey, or orange.

Anyway, this thing is huge! I told my wife "it fits in its own suitcase honey, it won't take up much room at all"....

I've assembed the telescope and am having a problem with its "Right Ascention" drive. I can't move the telescope from side to side with the hand controller. When I press the buttons to skew the scope I hear the motor working but the scope doesn't move.

The declanation motor and the motor focuser motors work as expected.

I belive this is probably why the original owner sold it to me...This was purchased at a VERY good price and the optics are flawless-the whole scope looks almost new.

I opened up the drive base and the worm gear doesn't appear to turn when the scope is skewing like it should. It almost looks like there is a belt connecting the motor to the worm gear shaft?

The electronics look ok, which is a relief because they would be hard to replace. Has anyone had a similar problem with a C-8 of that vintage? How would you remove the worm gear mechanism to check out the motor and the gearing? (I see two stainless steel screws holding the whole assemly to the base but when they are removed nothing budges).

There are two options for powering this scope, a 9V battery or a 12 V external (by using a jack) power source. Could my problem be that I am only using the 9V source?

I almost bid on that scope on *bay, it looked like a great deal.

You will not really be able to discern movement of the tube by eye on that scope when slewing. I had an Ultima, you will need to push it to targets. The motors are not designed to slew to targets like a goto. That being said, the drive in that scope is excellent, accurate, and reliable. The mount overall is very sturdy. A good scope for AP work if you don't mind manual guiding, though Shoestring Astronomy sells a kit that can be wired into your hand controller for autoguiding. You did well, that is a fine instrament...

Clear Skies

Tony Aguire