Telescope cleaning question

General Questions
#1

I have a new telescope, a Celestron C8N-GT. I haven’t used it yet, but I did take it outside to align the finder scope. Yesterday I looked inside of the tube, and found one of thost leeeetle nasty cedar seeds stuck to the mirror. :mad: I hate those things! Being nearly a meter long, the mirror is out of reach. I thought about spraying some compressed air to see if I could dislodge the seed, but I’m concerned about residue. Besides, the air is at the studio. Another possibility is to put a camel-hair brish on a stick and brush it off. But if it’s sticking – as those seeds do on my car – then there’s probably some schmutz that needs to be cleaned as well.

The most direct action would be to unscrew the bottom end of the 'scope, take the mirror and mirror-mount out, and clean the mirror. But I’m converned about collimation.

How should I clean my telescope?

#2

I regularly take mine apart and clean the mirror - the parts are designed to be disassembled for easy cleaning. Just be exact in putting them back - watch out for excess schmutz :slight_smile:

#3

I have no advice, but this reminds me of the first day I started a new job at a camera shop, selling cameras and telescopes.

A guy came in asking the best way to clean the mirror on his reflecting telescope.
He hadn’t used it in months, and when he got it out, he saw that a mouse had somehow gotten into the scope and had died and decayed on the mirror.
“Isn’t that horrible?” he said. And I had to agree.

#4

I would take it apart. You really need to collimate the telescope anyway after first getting it and occasionally afterwards. They will become unaligned over time just from undergoing temperature fluctuations. There are ways to get them roughly aligned without special tools. I can tell you how I collimate my 8" light bucket if you need to know.

#5

Make sure your housing is not filled with nitrogen before ripping it off. Some are…I forgot to mention this earlier.

#6

It’s not sealed. The mirror is at the bottom of a tube.

#7

I bet a single seed won’t have any noticeable effect on image quality. If it were me I wouldn’t do anything.

However, you shouldn’t be afraid to remove the mirror cell. Even if you don’t remove it, you should learn to collimate the telescope yourself. It’s quite possible it’s already been knocked out of alignment during shipment.

#8

I agree with scr4. Local spots on the mirror aren’t that bad, it’s the overall figure that maters most. The guy who made my telescope, Cave Optical in Long Beach, CA, said to use lots of purified water to avoid scratching it. Although small scratches aren’t that bad either.

#9

I took the back off of the telescope and found camel-hair brush in the box where I keep some camera supplies. Brushed off the offending seed, as well as a little dust.