Not at all, Bob, keep the Nagler. Sometimes you want high power with a wide field but top resolution isn't necessarily a criterion. Or if using a smaller scope with a short FL, even a 5mm eyepiece may not yeild an especially high power- yet you retain the wide field with the Nagler. TeleVue recognized the softness of the Nagler series, and better resolution was the motivation behind the Panoptic line. While a successful marketing strategy by uncle Al, a super-wide-field isn't the Holy Grail of eyepiece traits. Resolution will always be the top criterion of eyepiece (telescope) performance. A super-wide-field is usually an aesthetic concern, for most observing. Don's advice to go with better plossls (and I'll insert better orthos as well) is sound, for sharpest resolution. Keep the number of air-to-glass interfaces as low as possible, minimize total number of elements. With longer focal-ratio scopes, simple eyepieces can give incredibly sharp views. Remember that much of the purpose of all those lenses in super-wide-field eyepieces is to compensate for shortcomings inherent in low f-ratio Dobsonian primaries. My 3 cents. On 4/28/07, Bob Moore <BMoore@commercecrg.com> wrote:
Sounds like I now have a 5mm nagler for sale
Bob Moore Commerce CRG - Salt Lake City office 175 East 400 South, Suite 700 Salt Lake City, Utah 84111 Direct: 801-303-5418 Main: 801-322-2000 Fax: 801-322-2040 BMoore@commercecrg.com www.commercecrg.com
-----Original Message-----
From: utah-astronomy-bounces+bmoore=commercecrg.com@mailman.xmission.com [mailto:utah-astronomy-bounces+bmoore=commercecrg.com@mailman.xmission.c om] On Behalf Of Chuck Hards Sent: Friday, April 27, 2007 11:32 PM To: Utah Astronomy Subject: Re: [Utah-astronomy] Observing notes - Ealing 4-26-2007 Lunar visual
Based on my experience, Don is 100% correct- every Nagler I've used has been "soft" near the center of the field. Even my mid-priced orthos do better than Naglers as far as definition goes. This isn't noticed at low powers; at high powers typically used for plantary observation and close double-stars, wide-field isn't needed.
The Ealing can sometimes have troublesome tube currents for the first few hours of observation. It takes that big primary a while to cool down. But this is usually easily identified as separate from diffraction limitations.
On 4/27/07, Don J. Colton <djcolton@piol.com> wrote:
Unfortunately the Naglers do not do that well at high power because of the number of elements. I have found that good plossls, the Takahashi and the monocentric are the best performers.
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.utahastronomy.com
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.utahastronomy.com