100mm apo lens cleaning

[andaroo]

Just got my used Skywatcher 100ES pro apo - there is some stuff on both the outside and maybe the inside of the lens. Any top tips for cleaning - I know it should be kept to a minimum. I have a compressor with a small blow gun - can I use this even sparingly? i am more concerned about internal debris. There was no dust cap at the focuser end of the scope although it has hardly been used & is kept in the aluminium carry case. Thanks again.

[swamp thing]

I would be extremely skeptical about using a compressor as they don't blow dry air.

I know mine will collect moisture in the tank.

Regards Steve

[Tinker1947]

If your going to use air from a compressor there's filters need to be in-line to stop oil and moisture coming out.

Airline filters and Regulator valve assemblies

[glowjet]

It has been said not to use compressed air equipment or canned air as used in photography, as the contents can contain moisture, a large photographic bulb blower is best and a very clean and soft Camel hair brush, if the objective has an accumulation of dust on the inside you may have to live with it, another alternative, if it is very bad, is to remove the focuser unit, if you can, and put your brush on a long stick so you can reach inside but take great care and be very gentle, you could , of course, remove the objective, but I would take advise on doing that before you attempt it, otherwise you can have it professionally cleaned, I had mine done a couple of years back and it cost about £50 including carriage

[Tinker1947]

There are U-Tube Vids show how to clean mirrors ect, i think its like soapy water and a rinse, nothing to technical.

[Balder]

Air from a compressor can contain moisture as mentioned above but also oil residue from bore washing/blow by on the compressor's rings.

A lot of commercial "Canned Air" does contain moisture etc. However, "Ambersil" make a can of "Air Duster" which is a "Powerful, Dry, Inert Gas" (their words) It's good stuff, even got a NATO Cat. No. 6830-99-382611

[andaroo]

Thanks everyone - I'll calm ma jets as far as using the compressor.

[Herbig]

My advice is don't do it. It wont affect the image quality very much unless it's very dirty. If you really have to clean the outside carefully removing any grit or dust with a blower brush first, then use Baader Optical wonder on Baader microfibre cloth, do not apply pressure and work with a circular motion from the centre to the outside.

Don't try to dismantle it to get to the inside either, I speak from bitter experience!

As mentined above if you really want it clean get it done professionally £50 + carridge seems to be the going rate, I use Perran Optical Repairs - very friendly fast service, they were recomended by FLO sponsors of this site. they should come up if you google telescope repairs.

Get a replacement cap for the focuser. if nothing else put some cling film over it.

[ollypenrice]

A bit of dust makes far less difference than people think... My gear works very hard, does get mucky as a result, and I clean it as little as possible. When I do it makes no difference whatever!

Olly