Re: Cleaning optics
When tempted to keep your lenses constantly, perfectly, dust free - just say no!
Every time you clean your lenses, you subject them to a mistake on your part that can have long lasting ramifications. A little dust on the objective, or ocular for that matter, doesn't degrade the image in any way that our poor little eyes can actually see anyhow.
Now, a dirty little secret I found out about the hard way is the effect of suspended particles of tree sap/pollen that are released during spring and early summer. If you find a fine coating of hazy material (or if your lens turns a light shade of green!), clean it immediately! That stuff just will not come off completely after it dries...
Now when I do clean my telescopes, riflescopes and camera lenses, I use the same process.
Find the purest Isopropyl alcohol you can (right now, I've got 99+% pure). The rationale for this among my astronomer friends is that the detergents in the less pure stuff streak the lens and leave material behind.
Blow loose material off with low-pressure compressed air from the implement of your choice. Then, cotton swabs, with almost no pressure, should be used in a circular motion starting at the center of the lens and working outward. Be conscious of large particles that may scratch your glass. Change swabs often.
When the gunk is cleaned off, and only streaks are left, use a few Kleenex plain white unscented tissues (anal-retentive astronomers have found these to have the least amount of non-paper scented-lotion goo to further mess your lens up), with almost no pressure, first with a few drops of alcohol, then with less, to gently clean off the streaks.
[ 06-01-2003: Message edited by: STL_Shooter ]
STL. Principal Consultant and Managing Partner - Association of Bifurcated Tangential Ballistic Apologists, LLP.