Barrel size limits field of view only, not sharpness or contrast. Clarity, contrast, and sharpness are determined by the optical design itself, and quality of manufacture. Given "diffraction limited" lens surfaces, this means degree of polish, coatings, and quality control inspection. There aren't as many eyepiece manufacturers as you might think. Many low-cost brands are made on the same assembly line as "designer" brands, by the same OEM Asian manufacturers. Remember too that many manufacturers contract out their lens purchases and thus several manufacturers can use lenses from the same source. It's a global ecconomy these days, folks. What this means is that, when buying mass-produced eyepieces, you will probably get similar quality (and thus imagery) unless purchasing the absolute high-or-low end models, regardless of barrel size. And sometimes, though rarely, a lemon slips through the inspection process. Hope this helps.
-----Original Message----- From: steve.nielsen@comcast.net Sent: Aug 8, 2005 11:54 PM To: Utah-Astronomy@mailman.xmission.com Subject: [Utah-astronomy] Eyepieces
I have a dilema. I tried the new 17mm and compared it to the old and inexpensive 17mm a saw no noticeable difference. I looked at the moon, nebulas, clusters and M31. Not in that order of course. So I'm sending back the new 17mm. I'm within the 30 day period for a refund.
Why was there no noticeable difference? Does a 2" eyepiece give you better views and clarity than a 1.25" of equal size? It seems like it should to me. More glass surface in the lens. Please explain this to my tiny little brain.
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