Question about Celestron Celestar 8 Telescope

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Collimation screws on the Celestar C8

What are the sizes of the collimation screws on the Celestar C8. I need to replace one.

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If you are going to replace them contact "Bob's Knobs" and order the replacement thumb screws. Makes collimation much easier, no Allen wrench needed.

Posted on Oct 01, 2009


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I have a Celestar 8 .I need a replacement circuit board mfg by Tangent technologies part #TM5-3 , Any ideas on where to find one since celestron has discontinued to service this model .

Two possibilities--

1. Place a want ad on It will cost you $12 to join and put up the ad. There might be one in working order somewhere --- used.

2. Contact Ron Sampson on the Yahoo LX200 tech group-- join for free and post a message for him. Ron can repair any of the electronic boards from various telescope brands.

Good luck.

Jul 19, 2011 | Celestron Celestar 8 Telescope

2 Answers

Hi, I have bought a Meade DS-2102 MAK. It has a hint of misalignment with the airey disc slightly off center in the extra focal rings. I can't find any reference to which are the collimation screws. ...

Yes, you can do it.

Put the tube vertically on a table.

Remove the thumb wheel of regulation by unscrewing slightly the blocking screw with a key Allen of 1,5 mm.

Undo the 4 screws with a Phillips screwdriver.

Remove all the back part and you'll see the 6 screws of collimation.

The 3 longest are of use to the blocking, the shortest in the regulation.

Unscrew slightly the blocking screws before regulation.

It is necessary to make the little images of 2 mirrors coincide at the bottom inside the tube.

Also verify at the front part of the tube all the images of circles are concentric.

Don't block strongly the blocking screws after regulation.

Sorry for my bad English, I hope you'll understand.

Apr 09, 2011 | Meade DS-2102MAK (20103) Telescope

2 Answers

I lent my Celestron 9.25 SCT to a friend and he said he had collimation issues. He said he couldn't find the collimation screws on the secondary so he unseated the retainer ring and pulled the secondary...

Yes because the corrector plate must be replaced in the exact position it was removed. There were probably also small paper or cork "shims" around the glass plate that must also be replaced exactly. Your friend messed up your scope most likely.

YOU DO NOT need to remove the corrector plate to collimate an SCT. The collimation screws are on the center of the plate and accessible from in front of the scope.

Mar 08, 2011 | Celestron CG9-1/4 9.25-inch Schmidt...

1 Answer

I am trying to collimate a nexstar 130 slt scope but i am unable to see the 3 primary mounting clips thru the collimator. everything else seems to be in the center of the it collimated ok?

The primary mirror is adjusted from the bottom of the tube. A second person adjusting the screws while you look through the collimator is what you need to do.

Nov 21, 2010 | Optics

1 Answer

My c8 needs collimation done. i dont know how to do it step by step. can u pls help me? thanx, debbie

Yes, read these web sites:

Aug 24, 2010 | Optics

1 Answer

I bought a used Bushnell 114m reflector, needs alinement

I suppose you are talking about collimation is way off.

Read and watch these to get an idea of how to collimate a reflector

Feb 07, 2010 | Bushnell Optics

1 Answer

Celestar 8 dec knob assembly

Contact Celestron directly--

Jun 25, 2009 | Celestron Celestar 8 Deluxe Telescope

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