Though the dirt on the corrector lens may not cause much degradation of image quality, I think I should clean it now. There’s a lot of dust on the surface of the corrector lens and the two eyepieces. The inside of corrector lens has fungus grown on its surface and there are also some fingerprints on the front surface of the corrector lens [Some people have really fast hands. Even if I always tell people not to touch the optics or blow air on them someone manages to do it before I know it.]. I have just got the things I will need to clean the telescope optics.
I finally managed to get isopropyl alcohol (500ml jar) from a science equipments vendor (Sigma Trading Co.) at Pyakhal, Basantapur. It took a whole day searching for a place to find it. I moved from one camera vendor to another (since there are no telescope vendors here). I didn’t miss one camera repair shop in New Road thinking either they sold it or they knew where to find it. Fortunately, I found somebody who knew where to find it though it was tough time to locate the tole where the vendor was located.
To blow off the dust, I needed either an air blower (an ear syringe as written in the telescope catalogue) or a camel hair brush. But did you know a camel hair brush is not made of camel hair? Well, I didn’t know that and kept searching for a true camel hair brush. In fact, Camel is the name of the person who invented it and hairs of ox, goat, squirrel, etc are used in this type of brush. I also paint sometimes because I like painting and I do have a set of brushes. I don’t know if I can use any of them to dust off the optics.
I have also bought a few packs of non perfumed facial tissues from Park ‘n Shop supermarket, Khichapokhari to use with isopropyl alcohol to clean the lenses. As suggested by the maintenance guidelines in the catalog I will have to clean the lenses with the tissues dampened (but not too wet) with 3 parts distilled water to 1 part isopropyl alcohol.
Still, I am yet to clean them.
[We are using the Meade ETX 90 mm donated by Permission To Dream of US. The picture posted here is my favorite one and have used in several places. An old lady is gasping over the Moon she is seeing through the eyepiece while an observation session at Bhrikuti International School, Gaighat in 2006.]