Clean mirrors!

[JamesC]

I got my 12" dob in late 2008 and decided it was about time I cleaned the mirrors. They looked very speckled in torch light and I thought a spring clean might help the spring galaxies.

Dunno how advisable any of this is, but I started with the secondary mirror. With the lid protecting the primary mirror I gently pushed blue tack around where the mirror is glued to the holder to protect the glue from water (I didn't fancy re-gluing the secondary, although I would have done it if it had come off). I then removed the entire spider and took a look at the secondary. To be honest it wasn't that bad, but since I had it out I decided to give it a rinse. I put on some washing up liquid and then washed it off. I even took it to the shower and gave it a low pressure wash there. It wasn't nearly dirty enough to justify touching the mirror with anything so I didn't. I then rinsed it off with deionised water, blew off most of the drops with one of those optical blower things and then put it back in the scope and took off the blue tack. It looks much better under torch light now.

Next I took out the primary mirror and this time it really was dusty. I was surprised how thick the glass was - about 38mm! Gave it a rinse, put on washing up liquid and then washed it off. Gave it a soak. Took it to the shower (is this overkill?). Rinsed it off with deionised water, got rid of the water drops and then remounted it. Luckily the centre spot didn't unstick.

Next I recollimated my scope. Now I have a very clean telescope all ready for the spring galaxies! Hope I haven't done anything too inadvisable.

[tyke]

Im sure someone will be along later to tell you that it was totally unnecessary to clean your optics unless there was 3 inch of top soil on them