Something on my main mirror.

[Manok101]

I can occasionally see it, and am not sure if it is just collected dew or dust or scratches or what, but with my red light it reflects whiteish, if it is more than dew, how do I clean it without ruining the coating?

[Nexus 6]

Hi Manok, I think you should have a look in the daytime. If you do need to clean it there are plenty options.

look here

http://www.celestron.com/c3/support3/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=1738&nav=0

Alan

[ollypenrice]

If you are struggling to see it, leave it alone! Flashlights invent defects single handed...

Olly

[dweller25]

I doubt it's effecting the views. I would just leave it. As Olly says shining a flashlight will ALWAYS give unnecessary cause for concern.

[umadog]

Mirrors always look dirtier with a flashlight. Leave it be.

[solo]

Hi Manok,

Last winter my mirror looked dead grotty so I cleaned it in the summer using the tried and tested cotton wool/distilled water method. It also has a piece of the reflective coating missing about the size of a pea. To be honest, the mirror performs just the same as before I cleaned it. For example, I can still easily make out the E & F stars in the trapezium under good conditions as well as I could before. So my advice - leave it be.

Cheers, John.

[Hypernova]

I have seen the stuff you have described on my mirror and I still can see it to this day even after I good clean a few months ago and even a Hilux re-coating from OO on the house.

I assume it is either just slight imperfections in the reflective coatings or just a thin layer of dust that has settled on the surface that doesn't want to blow away, either way I don't think affects the views I get at all but I agree it can look quite shocking when you shine a torch down the tube to have a look.