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Repair Manuals

robindurant

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philsail1

philsail1

Posted
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Hello Robin!

I think I have the same set up as you:- A clestron CG5 "GoTo" and a Celestron C8i Maksutov/Schmitt Cassegrain (I don't really know the difference!).

Is your GoTo enclosed by a large plastic shroud? The clicking could be from a loose wire catching on the motor as it turns. Or perhaps, part of the plastic casing is catching the motor?

What is the problem with your scope? (I recently took mine apart to paint the tube white. I am waiting for some clear weather to check it's collimation is 100%.

I don't know much about the mechanics of this scope, but I could try and help.

(I can't find any repair manuals either - but if I do, I'll let you know).

Regards,

philsail

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robindurant

robindurant

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Hi Philsail

The Scope is only a potential problem, possibly, which if I had a breakdown drawing I would know.

I want to know if you can damage the focusing mechanism by over winding. The reason I ask is that when I reach the end of the wind, either in or out, it gives a clicking sound as though some connection or gear is jumping off it connection. This may be OK, who knows.

The Mount as you say may be down the Plastic content of its construction..

Many thanks for your concern

Robin

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philsail1

philsail1

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Hello Robin,

"I want to know if you can damage the focusing mechanism by over winding. The reason I ask is that when I reach the end of the wind, either in or out, it gives a clicking sound as though some connection or gear is jumping off it connection. This may be OK, who knows."

My C8 has had its focuser changed at some point in its "chequered" history, to a sophisticated dual speed focuser. I have on several occasions wound the focuser right "in" and all the way "out" again, and it doesn't give any "clicking" sounds - it just comes to a dead stop and locks up.

Unfortunately, (if yours is the same as mine) whilst it's not beyond a reasonably competent person, it is not the easiest scope to dismantle. You have to remove the front glass corrector plate (complete with secondary mirror) to enable you to reach inside to catch the six small nuts (near the main mirror) whilst you undo them from the outside! it can be done though. You simply have to mark the positions of the tube and plastic ends so they go back in the correct places, and then wind the main mirror back as far as it will go - to clear enough space to get your fingers to the small nuts holding the rear end to the scope's body. Also you need to keep the scope verticall upright whilst removing the six tiny hex bolts on the front corrector plate, so that when you remove the large plastic ring holding the corrector plate, you can see where the positioning shims lie around the edge of the corrector plate. You need to do a drawing of this position. or photograph, or mark with tape where they lie, so they can be positioned correctly on reassembly.

On, reassembly you need to be very careful that you do not accidently get grease from the central tube, onto the main mirror. (I had covered my main mirror with a plastic bag whilst it was out of the tube, and when I removed the bag to put mirror back in tube, a spot of grease caught the edge of the mirror. Fortunately I was able to successfully get it off with a tiny dab of diluted washing liquid on a cotton bud - caused me to sweat though!). When you put the front corrector plate on you need to position the "shims" as they were, and ensure the corrector plate is centralised and in exactly the same position and orientation to the main mirror as it was prior to removal. You will still need to collimate the scope afterwards, using a Cheshire (or Laser) and a star test too. (I'm still waiting for a clear night to check mine).

I'm not thinking that you are going to strip your scope down Robin, but I just thought I would let you know what I experienced.

I can understand your worries, when you hear a strange or unusual noise from a piece of equipement. Anyone would certainly want to find the cause and try and put it right.

I will check the photos I took of the mirror when it was out of tube, and see if any of the mechanism is showing.

Regards,

Philsail1

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