C9.25 corrector plate - dust/dirt/dew

[Jammy]

I've not had my C9.25 very long but I've noticed speckles of dirt developing on the corrector plate.

I don't want to do anything to damage the scope, but wondered if it is ok to clean it? And if so, what do you use to do it?

When I de-focus to check collimation the dirt marks are very clear within the de-focused image. However, I don't think they affect the focused images.

Thanks for your help.

[E621Keith]

I'd leave it alone unless the corrector plate is really dirty or there are sign of fungus.

I used a rocket blower to remove as much dust as possible, then I use Baader wonder fluid and micro cloth to do the final cleaning.

[Northern Soul man]

Hi Jammy, probably not dirt on the corrector your seeing, next time you de focus, loosen the ep and look through at the same time whilst rotating the ep - if the muck rotates - you know it may just be the ep that has a little muck on it. Cheers Paul.

[michael.h.f.wilkinson]

Muck on the EP can be cleaned in the same way as described by Keith: blow away the dust and clean gently with Baader wonder fluid

[Freddie]

Plus 1 for Keith's comments. Don't touch unless you REALLY need to. I have cleaned mine once in the last year, but use a blower reasonably often.

[Jammy]

Thanks guys. I hadn't thought about the eyepiece - I'll have a look at that first.

The corrector plate only has a couple of speckles of dust. I'll have to get an air blower.

[red dwalf]

i do what Keith does, only as i had a look on the inside of the corrector plate and noticed what looked like mold or fungus, this does need to be removed,

it`s an easy enough job, but mark the outside of the glass with a alittle tape and the tube so that when you put it all back together it`s in the same place, then do a star test

[Jammy]

You were right about the eyepiece. I tried a different one and everything was fine. Another clear night last night.

[Northern Soul man]

Nice 1 Jammy, a lot of people worry about the corrector plate - but what you have to think is that telescopes are used in an environment where they are going to get dewed up and dirt on them - people seem to think when they purchase a second hand SCT - the optics must be perfect, but to be honest, the coatings on these correctors are pretty robust and 10/20 year old scopes are still around and working fine. I know that the coatings have come along way since then.

Also the corrector plate is at the front of the scope and the point of focus is at the back of the scope - so any marks or dust will literally be "invisible" in the focal plane - just something to bear in mind when seeing a little dust on the corrector. Cheers Paul.