Yesterday evening I got home from work and took the dog out for his walk. It was a lovely clear night and the stars were nice and bright, so I was feeling quite excited about the prospect of some decent star gazing (wifey is away tonight). Got back home and immediately took my XT10i telescope outside to start cooling down. Next I went in, did the dogs supper and prepared myself some tea, and ate it quickly so I could get back out for some observing. I was about 20 minutes in all. Went back outside and couldn’t believe it. Once again those blasted clouds had moved in to spoil the fun. Damn!
Oh well. Plan B. At the weekend I had ordered some Protostar black velvet flocking material to line the inside of the scope to reduce reflections from ambient light bouncing off the insides, and so increasing the contrast of the view. And it had just been delivered that morning.
So I set about carefully dismantling the scope to remove the primary and secondary mirrors, and the finder scopes, so I could install strips of the flocking material easily. The job took about 2.5 hours, by which time it was too late to put everything back together.
Tonight I decided to finish the job by cleaning both primary and secondary mirrors, and adding a touch of black matt paint to various bolts inside that were shiny, and apply some to the edges and back face of the secondary mirror. I carefully followed instructions for the best method to clean the mirrors, so as not to scratch them or remove their aluminised protective coating (I’ve had the scope almost a year now and a fair amount of dust has gathered on the primary).
Finally I re-assembled everything and re-collimated the mirrors as precisely as I could. When all was done I took the scope outside to see what improvement the flocking had given. It’s been a fairly clear night, with the occasional cloud passing over. The Pleiades were visible so I lined up on them and checked it out.
Now my rear garden has a white light (mercury) street lamp to the North side, and I have always noticed when pointing the scope to the North or East, that the light entering the end of the scope tube (unless I get our large patio table umbrella out to shield the light) always gives a lightening or greyness to the view. But with the new flocking there is a considerable difference, with a very much darker view, which does indeed give better contrast. Certainly looking down into the tube from the top it looks very dark inside.
Nice one. As usual I have taken some photos of the flocking work, and will create a new page in my main web site describing how it was done, and where I got the material from. Watch this Space.