Orpington Astronomical Society

Astronomy => Technical => Topic started by: MarkS on May 08, 2008, 12:42:51

Title: How to clean SCT optics?
Post by: MarkS on May 08, 2008, 12:42:51
Quote from: Mike
... everything is covered in dust (though not quite as bad as the front cell on your Celestron Mark ;) )

O.K. I get the hint - I'm obviously using the scope far too much.  ;)

But what's the best way of cleaning dust/grime from the corrector plate of an SCT?
Title: Re: How to clean SCT optics?
Post by: Ian on May 08, 2008, 12:45:28
point at zenith.

remove secondary.

remove eyepiece.

insert hosepipe in eyepiece hole.

Turn on tap until water comes out of secondary hole.

Allow to drain.

Give secondary a good scrubbing with a brillo pad.

Bring it round and I can do it for you this afternoon :D
Title: Re: How to clean SCT optics?
Post by: Tony G on May 08, 2008, 12:59:29
What temp. should the water be Ian ???????????? :-?

Tony G

PS it doesn't work with boiling water!
Title: Re: How to clean SCT optics?
Post by: Ian on May 08, 2008, 13:03:06
I'd use water that's just above freezing point.

If you remove the corrector plate, you can fill the tube with beer cans which will be chilled perfectly by the time the process is complete.

You can then use the corrector to light the barbie without matches. Or burn ants. Or next door's cat.

I wouldn't recommend using boiling water, it'd ruin the coatings.
Title: Re: How to clean SCT optics?
Post by: Mike on May 08, 2008, 13:10:48
I am sat at my desk in work chuckling away here after reading Ian's reply and everyone is giving me funny looks.

OK Mark, this is the way I clean my filters and optics about once a year.............

Make a solution of lukewarm water (about a litre) and place in it ONE drop of washing up liquid.

Using either a soft lens cleaning cloth or a very soft artists paintbrush, or one of those wide ladies makeup brushes, clean the lens carefully and gently.

Once clean, rinse it off thoroughly using distilled water. You can get 5 litre bottles from Halfords for about £3.

Leave to dry naturally.

Title: Re: How to clean SCT optics?
Post by: RobertM on May 08, 2008, 13:29:07
Ian,  If you have a Barbie then I would keep it to yourself, it's not normal for men to have them.  I do however entirely agree with lighting them with matches, that shows you are (relatively) normal after all ;)
Title: Re: How to clean SCT optics?
Post by: Ian on May 08, 2008, 13:48:25
I was going to get one barbie for my action men.

Then I decided it would be better to have a box of barbies and one action man. See if he can live up to his name...
Title: Re: How to clean SCT optics?
Post by: Tony G on May 08, 2008, 16:03:21
What if, your Action Man only had eagle eyes for another Action Man, you know the one with the gripping hands and fuzzy head, then all those Barbies in the box, would be wasted on him (it would be like Hugh in the Playboy mansion) :D

Tony G
Title: Re: How to clean SCT optics?
Post by: Ian on May 08, 2008, 16:26:23
A huge what in the playboy mansion?

A whole box of Barbies with no action men in sight... I bet if I googled, I'd find a "special interest" website all about that. probably with pay to view photos.

So, Mark is your SCT clean yet? (got to make some effort in bringing this topic back on course, I saw Rick looking in... ;) )