Incorrect Corrector lens?

[mark7331]

Hi all. I have a 6" celestron SCT and I've notice that the corrector lens (the bit of glass at the front?) appears to have white streaks on the inside. I've attached an image to show you what I mean. I've upped the levels so the photo shows more clearly.

Is this a problem? If so can I repair it or would it be best done buy an expert?

Thanks in advance.

Mark

[Merlin66]

Looks like the typical condensation/ outgassing film that these things do get.

It's pretty straight forward to remove the corrector and clean this film.

Google "SCT strip down" or similar.

Ken

[johninderby]

Good article here on the NexStar site.

http://www.nexstarsite.com/OddsNEnds/SCTCorrectorRemoval.htm

And use Baader Optical Wonder cleaning fluid and the Baader microfine cloth as it won't damage the coatings on the corrector plate.

John

[mark7331]

Ken, John - thanks very much for the info & advice. I'll order the fluid & cloth and have a go.

Mark

[mark7331]

An update: I've just clean the lens and removed lots of debris from the secondary (very gently). I took a flat before and one after I clean the scope and the difference is quite amazing. The amount of noise in the post clean flat is just a little less than half of the pre clean flat. Optics look so much clearer too.

Many thanks for the help & advice all and FLO for supplying me with the cleaning fluid and cloth so quickly.

Mark

[JohnC]

Great result.

[Merlin66]

Glad everything worked out for you!

Ken