Cleaning optics: Mak meniscus lens has a spot on it!

[Ags]

I have owned a 102mm Mak for a couple of months, and I've just noticed that aside from some dust I'm not worried about, there is somehow a spot on the meniscus lens, about the size of a grain of rice - like something liquid went splat againt the lens.

I know the advice is to avoid cleaning the optics - but what should I do? Does that apply in this case, or is the advice only applicable to dust? I keep thinking that maybe this spot will damage the lens...

Feel free to tell me if I'm being an obsessive worryguts - I'm just very proud of my little telescope.

[johninderby]

Baader Optical Wonder fluid, simply the best and safest way to clean a MAK lens. The coating on the lens is actually fairly tough and the Baader fluid won't damage the lens at all. Of course blow any loose dirt / dust off first.

You can get it from FLO or most other astro shops.

John

[NGC 1502]

Optics can look very grotty and still work ok. But when the time comes &

you just can't stand it any longer, the front meniscus can be very carefully

cleaned with isopropyl alcohol ( from chemist ) & a microfibre cloth ( from a

good photo shop )

But don't pour the alcohol on the glass, just use a little on the cloth, and as

John says in post #2, blow away any loose crud first.

Cheers, Ed.

[Eddie]

I would not bother cleaning such a small spot, this will have no effect on the performance of the scope.

Also using neat IPA, even on the cloth could damage the coatings on the optics. It is best to mix it with some distilled water (or cooled boiled water if you don't have any distilled water), do a 50% mix.

HTH,

Eddie

[Ags]

Thanks everyone - I will live with the spot for a while, and invest in some cleaning fluid as suggested at a distant point in the future.

[Capricorn]

The front glass isn't exactly delicate.

Take a bit of care and clean it.:D

Have a read of the people that have dropped and dented Maks and SCTs. They nearly all say that the OTA is dented and/or are bothered about alignment/collimation, which if the front glass had shattered would be immaterial.

Also you clean your windows with an assortment of chemicals and never give that a thought. And they are a lot better afterwards, they don't come up diffuse owing to multiple scratches or opaque owing to chemical reaction.

Think about all that carbonic acid that forms on the front plate in the form of dew.

[great_bear]

The front glass isn't exactly delicate.

Take a bit of care and clean it.:D

Absolutely!

I have a seven-inch Mak, as well as a four-inch one, and I don't - and won't - think twice about cleaning either one of them.

I just use a microfibre cloth from Tescos. I just breath on the spots and gently wipe clean. If a spot is very tricky I will use a lens pen,