Mirror cleansing

After a number of years of use, the mirror of the observatory’s 30 cm (12″) telescope was in need of a thorough cleansing.  We used distilled water to soak the surface of the mirror and to get rid of insects, pollen and other dirt. More water was used for a final rinse. The central hole of the mirror shows signs of wear and oxidation, so we probably need to have it recoated in the near future. With a brush we wiped the inside of the tube clean, after which the original matt finish re-appeared.