Secondary mirror cleaning

[8472]

Right, whilst finally managing to successfully collimate my Dob, i've noticed the secondary seems to have about 2 minute specks of dust on the surface.

I know the general opinion on the primary is to leave well alone in the same situation, but does this same advice apply to the secondary too?

Thanks!

[umadog]

Ignore them or blow off with a squeezy bulb camera blower. Rocket Blowers are good. Research indicates that coatings last longer if they're washed every few months; so if you're careful about doing it, there's good reason to keep your mirror clean. Personally, I hose it down with distilled water and leave to air-dry periodically. This is safe since I'm not even touching it with cotton wool.

[8472]

Thanks for that.

I'm pretty sue i've a bottle of distilled water in my garage, so i may give it a wash next time i need to collimate.

[swamp thing]

Just make sure it's Distilled water and not de-ionised. As there is a difference, and you shouldn't use de-ionised on optics.