Cleaning a Diagonal

[Teslar]

I recently bought a second user WO Diagonal which could do with a clean. The mirror is a little dirty with what looks like it has settled on the surface but can't be blown off with my hurricane blower. What's the recommended process for cleaning a diagonal folks I've not cleaned one before

[hypnotoad]

Hi

I think you will have to basically clean the mirror as you would in a reflecting telescope, in terms of cleaning materials.

You could try using a swab of cotton wool soaked in alcohol fitted to ear bud stick or similar. The cotton on the ear bud itself

is too compact and there is not enough, so you have to carefully add a little bit more. Just lightly run the soaked cotton wool over the surface. Or use a very weak soap solution soaked into the cotton wool maybe better if its really dirty. The water should be distilled, not tap water as this can stain the mirror. Don`t go mad cleaning if there is just dirt, as this does have much impact visually.

regards

hypnotoad

[hypnotoad]

Hi

I should say a little dirt. I missed that bit out.

[Herbig]

You don't say which type of WO diagonal?

I have a carbon fibre one the sides of which can be removed for better access to the mirror.

Like any good scope though the advice would be leave alone if possible, some mirror surfaces can be easily damaged.

If I had to I'd moisten the surface with Isopropyl alchohol as suggested above and then rinse by pouring it over the surface, do not rub the surface.

[Teslar]

Thanks, yes it is the carbon fibre one. I'll check it out this weekend. I was planning to buy some Baader Fluid but waiting to see what others suggest first

[johninderby]

The protective dielectric coating is actually very tough and can stand a lot of abuse, so you don't need anything special to clean it. The dielectric coatings were originally developed for military use where they could be cleaned with a dirty rag and a bit of spit or anything else handy. They are nothing like a regular telescope mirror or objective.

So you don't have to worry about cleaning it.

John

[Teslar]

Well I never knew that thanks. But it kinda goes against the grain so I'll be careful anyway

[johninderby]

I admit that even though I know how tough the dielectric coatings are I use the Baader fluid anyway.

John