[Shiraz (Ray)]

Hi

have been trying to chase down an annoying feature of my Newtonian optics - they generate a significant amount of close scatter around bright stars.

1. removed the spiders web from the baffles in the OTA and washed the mirrors. Didn't really help.
2 repainted the interior of the OTA with chalkboard paint. Slight improvement.
3. closer inspection of the mirrors - maybe the surface is giving way. Not too bad, but could see a slight filminess using an off angle bright torch - ahaaah. tried washing with detergent, windex, alcohol, acetone - still there, nothing touched it. In desperation, tried some wax and grease remover from the local hardware - this is light petroleum distillate and it removed the film after a few applications. wash with distilled water and the mirrors looked nice. However, there was still a lot of scatter.
4. this morning, removed the coma corrector - sure enough that had a light film as well, which was gingerly attacked with the wax and grease remover(hoping none of it would wick inside the CC). all went OK and now that looks clean as well.

Don't know what the film was, but suspect that it has something to do with the wood fires that all of the near neighbours use - could be some form of vapourised gum I guess. This is a seaside, rural and mining town, so it could also have come from other sources I guess. anyone got any ideas? Anyway, now have to test it out when the clouds clear and see how much improvement there is - hoping.

thanks for reading. regards Ray