I leave my LX-200 in my observatory all winter long. Up here in Cache Valley it will get as low as about -25F. In the winter I do leave my desert storm bag covering the scope and I have a 40 watt bulb inside the bag to help keep it dry. Concerning Paul's original questions, if you do opt for a dew shield, I've had great success with the "insulated dew shields". You can find them at www.dewshields.com As Brent alluded dew is very bad for your scope. If you bring your scope inside after observing in the cold you should leave the cap off until everything has evaporated. Otherwise you might get mold and other bad stuff forming on your corrector plate and other parts of the scope. Clear skies, Dale.
-----Original Message----- From: Joe Bauman [mailto:bau@desnews.com] Sent: Tuesday, November 18, 2003 7:53 AM To: Utah Astronomy Subject: Re: [Utah-astronomy] Question about dew.
Brent, I have been thinking about doing that. I have an LX200, and my concern is that the intense cold of winter might damage the computer or somehow freeze up the gears, if it's left at subfreezing temperatures for weeks. But I don't know. Any thoughts on that? Thanks, Joe
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Quite informative, Dale. How cold do you think the computer part of the telescope gets? And what if I left my LX-200 in a shed with plastic bags completely covering it? Thanks again, Joe
Joe, Chuck here. Dew is prevented by keeping whatever you're interested in keeping dry at a temperature above the dew point. This is never warm to the touch under most conditions, just not quite as cold as ambient temperature. In the field, a "dewcap" prevents objectives (or corrector plates) from chilling too quickly. To extend this time, extend the dewcap. 1-1/2 diameters is standard. The best coverings are "breathable", impermeable plastic only serves to trap moisture inside. Mylar covers are for daytime, dust protection only. Some "experts" have advocated keeping a bowl or cloth bag of silica gell crystals inside telescopes stored outside, and heating the crystals in the oven every few weeks to dry them out. Personally, in 35 years of observing, I've had a problem with dew exactly once, and that was with a scope left on the lawn all night. Scopes in sheds or observatories will not accumulate dew unless they are colder than ambient temperature; not really possible after the roof or slit closes up. C. --- Joe Bauman <bau@desnews.com> wrote:
Quite informative, Dale. How cold do you think the computer part of the telescope gets? And what if I left my LX-200 in a shed with plastic bags completely covering it? Thanks again, Joe
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Hi, Chuck. With a computerized drive, will the winter cold damage anything? Thanks, Joe
--- Joe Bauman <bau@desnews.com> wrote:
Hi, Chuck. With a computerized drive, will the winter cold damage anything? Thanks, Joe
Only your fingers and toes! Joe, computers are shipped to stores in unheated trucks, stored on unheated docks and warehouses, sometime for months. Should'nt cause any damage at all. The computer may be a bit sluggish until it warms up, though. Couple of minutes. Early generations of LCD displays were susceptible to freezing damage, I think the newer ones are much more cold-tolerant. About the biggest "cold" concern is gelling of lubricants. Hopefully Celestron realizes this and has used low-temp lubricants. I'd say read the owners manual. If there is no specific warning about protection from freezing, you have no worries. If there is, follow the manufacturers instructions. C. __________________________________ Do you Yahoo!? Protect your identity with Yahoo! Mail AddressGuard http://antispam.yahoo.com/whatsnewfree
participants (3)
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Chuck Hards -
Dale Hooper -
Joe Bauman