care of my refractor?

Question

I just purchased a WO megrez 90 refractor. I do not know how to care for the lens and want to keep it in like new condition if I can. The other night I was observing with it and dew formed on the objective lens. What is the best thing for me to do when this happens? Can a dew buster be used on refractors? If I have to clean lens what is the best way to do it?

Answer 1

Optics should not be cleaned too often. I clean my refractor's lens every couple of years. You might check William Optics to see if they have any cleaning recommendations. Astro-Physics sells a cleaning kit for their refractors: http://www.astro-physics.com/products/accessories/cleaningproducts/optcs-instructions.pdf

I start by blowing off any loose dust with canned air, and then gently dusting with a camel's-hair brush. After that, I clean using surgical cotton and three different cleaning solutions: filtered water with a drop of dish detergent, isopropyl alcohol (99%), and acetone. Each solution will remove different types of crud. For spots of organic crud, a little saliva on a fingertip sometimes gets it, then clean up with alcohol or acetone. Wipe very gently, especially on the first couple of passes. to avoid scratching. Don't flood the lens, or you may get liquid inside the lens cell. And be very careful with the acetone - it dissolves paint and plastics. And don't be obsessive. If there's a spot that just won't come off, leave it. Trying to scrub it off will probably do more damage than help.

For dew, the best strategy is to prevent it. A good dew shield is often enough. I have a Just-Cheney insulated dew shield that works really well. The DewBuster or other heating strip will work too. In really bad conditions, heat may be the only way to keep dew off your optics.

Answer 2

First of all, try never to touch or wipe the face of the lens with anything if at all possible. Photography/camera shops are an excellent place to buy lens-cleaning supplies. There are squeeze bulbs that blow air onto the lens to remove dust without touching it, as well of cans of air made just for this purpose. You can also purchase lens-cleaning brushes made with some type of very soft bristles that work well for this. As far as the dew problem, you can easily make (or even buy) a tube-like extension that slips over the front of the telescope's front that are called "dew shields" (of course). Since refractor telescopes usually have a narrow "field of view", this tube extension won't affect what you can see through it at all. In fact, since these tube extensions tend to block stray light sources from reaching the front lens, they work to enhance the eyepiece view by enhancing contrast too!

Answer 3

First, you chose very well and bought a fine scope. I have a friend with one and the reviews I have read are all wonderful.

Yes, you should get a dew heater if you go where dew or frost can be a problem. The best thing to do is to never touch your lens. If your lens gets dusty, blow it with air but not the canned kind as the propellants leave a residue. Get one of those photographic bulb type of air squirter things that manually blows the air to get the dust off. There are a lot of people with very definate ideas of cleaning soloutions that should or should not be used. Less is best. You might want to try to join the Williams Optics yahoo group for better information, but if it were me, I would get advice from the makers, W.O. direct, for what cleaning soloution to use so that you do not damage any coatings. A scope that nice is worth the extra effort.

Answer 4

For your dew problem, buy yourself a small hair dryer. Use it to blow dry the dew off your objective.
They are a lot cheaper than a dew zapper. The money saved can go toward other astro goodies.
After a dewy nights observing, wipe the exterior of your scope down before packing it away. Use an old T Shirt, it is soft so you won't accidently scratch your scope.
Definately join the william optics forum. Lots of good advice to be had.

Answer 5

Lots of good advice here. One further tip: attach a small bag or container of silica gel to the inside of your lens cap. Then, if the lens dews up, you can attach the lens cap and it will absorb the trapped moisture.

Answer 6

Dew gets much deserved attention, the other killer is dust. Keep your telescope covered at the very least or cased.