Cleaning

[valleyman]

I have noticed on my new Celestron C8 Cassegrain some misting on the inside surface of the front appeture, (the part that holds the corrector unit).

Should I attempt to remove the front cover to clean inside. I have noticed there are four screws holding a metal ring immediatly in front of the appeture. I would welcome some advice from other C8 owners as to what would be the best thing to do.

[Doc]

I found this on the web. I think it's from a proper Celestron dealership:

Q: How can I clean the corrector plate on my Schmidt-Cassegrain telescope?

A: The outside of the corrector plate can be cleaned using a solution of 60% distilled water and 40% isopropyl alcohol with one drop of clear liquid dish soap per quart of solution. The solution is applied to a soft tissue or cotton ball and is carefully rubbed onto the corrector plate using radial strokes from the secondary mirror housing outward. We do not recommend removing the corrector plate. The corrector plate is optically matched to the mirrors in alignment and in rotation. If the inside of the corrector plate or mirrors becomes dirty, call Celestron and arrange to send your telescope in for a thorough cleaning. Celestron offers complete cleaning and collimating services. Contact the Technical Service Department at (310) 328-9560.

[Capricorn]

If the inside then any cleaning would mean wiping over the reflective section and not sure how well protected this is. So a point of concern. The alignment and setting sounds as if you could upset it. Equally I thought that you could collimate them?

I would say that sending it back to Celestron is not really practical.

Best I can think of is an email to telescopeplus.co.uk. They were D Hinds and are, I think, the Celestron importers. Ask if they can suggest someone or if they could do the work.

If they are not the importers they were a major Celestron retailer so may still be able to help.

[valleyman]

Took a deep breath last yesterday and decided to remove the collimating mirror plate for cleaning. It could not have been simplier. First marked the postion of the Collimater in relation to the Tube. Then removed the 6 screws and removed the outer ring and two felt pressure pads noting there location.

Then the whole Collimater plate just came out easy.

Did the cleaning and reassembled. Waited for a star last night to check the Collimation and it was just about 95% perfect.

Had a quick look at M29 and went to bed happy with the results.