Been putting it off for quite a while, thought cleaning telescope mirrors was akin to an act of heresy. But after checking out Mikes mirror cleaning article and asking heaps of questions, today I did the unthinkable and washed my 16" primary mirror.
Thought I might kill two birds with one stone and give my scope a complete overhaul. My tube is very heavy walled cardboard and I have never been happy with the finish inside the tube. It was black but shining a light down it resulted in numerous reflections.
My day started with the removal of my 27 point primary mirror cell and the removal of my secondary mirror. Stored them in a secure place then, using a pipe paint roller, I painted the interior of my tube with Dulux flat black. Beforehand I mixed 300g of non slip powder into about half a litre of paint. It is fairly thick and I applied a second coat after the first dried.
Love the finish, its like the surface of very coarse wet & dry sand paper. Looking down into the tube is now like looking into the abyss.
Prepared the S/S laundry wash trough, can't fit a 16" mirror into the kitchen sink. Put about 6" of warm water in with about 5 drops of dish washering liquid. Went over my mirror with a large capacity camera lens blower, did the same with my secondary.
Very carefully carried my primary mirror from my observatory up into the laundry and gently lowered it into the water, then left it for 15 minutes.
Came back and tried just lifting the mirror a little side to side, letting the water flow across it.
Still seemed to have some stubborn material on it so broke open my new bag of cotton wool buds and extremely gently wiped the mirror surface. Used two buds at a time but disposed of them after each wipe. I could see a definite discoloration on some of the buds, so they had to be removing something.
Gave the mirror a final gentle gyration, then sat it up on its edge and pulled the plug. Placed a folded towel under the edge of the mirror and rinsed with about 2 litres of Diggers demineralized water. Opened a fresh roll of Viva paper towel and folded pieces of it, using the edges of it to suck up the last few water drops that clung to the mirror.
Put the mirror back in it's cell and re installed in the tube, re fitted my secondary which is in really excellent nick for a 14 yr old mirror and collimated the scope.
Before cleaning my mirror, when using my double pass Ezy Collimator, the dust on the primary scattered the laser significantly but now there is just a nice bright red dot on the primary and the return beam is much better defined.
Having now bitten the bullet and done this I would not hesitate to do it again, perhaps in another 14 yrs.
Thanks for posting your mirror cleaning article Mike, eventually I built up enough courage to have a go at it. I suppose it really has been a ground breaking year for me since coming on IIS, in many different ways.
Looking forward to more contrast in my Saturn images.
I have posted a series of photo's of my mntce.
Image 1. The view down my tube before painting.
Image 2. The paint and non skid additive and pipe paint roller.
Image 3. My primary mirror in my 27 piont cell before I washed the mirror.
Image 4. My secondary mirror still looks great after 14 yrs.
Image 5. My nice clean, freshly washed mirror back in it's cell.
Image 6. Looking into my tube now is like looking into a black abyss.
hope the spit and polish makes your images brighter and better, be good to see if there is a difference (OK i know the seeing and transparency come into the mix). good to see you were brave enough this close to a dark moon to take on the job!
