Re: [Utah-astronomy] Eyepieces
Hi Steve, I haven't spent but a few minutes with any Lanthanum eyepiece, so I can't really comment about the overall quality. But I think their main claim to fame is long eye-relief. This is a tremendous benefit to folks who must wear eyeglasses when they observe. But it seems that of the people who observe without glasses, very few choose the Lanthanums. If you were willing to spend $245 on an eyepiece, you've got a lot of options. The Celestron Axioms aren't bad. They're not up there with Panoptics, but they're half the price and are very good except at the edges. The Harry Siebert's aren't bad in that price range, although they're sort of crude looking. And you might want to wait a couple of months to see if Televue does another holiday special. I picked up a 13mm Nagler last year for $250 (about $50 off), so perhaps they'll do something like that again. F/8 is a real nice place for a 12.5" scope. and you should be able to use just about any eyepiece you like in it. Michael -----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 have a 12.5" f 8 I made in one of Brent Watson's workshops. You know, the one where 8 or 9 people in trench coats wait for the sun to go down and then they all drive seperately to an airplane hanger to grind mirrors. Sounds like something from a Dick Tracy cartoon. Oops, I'm off topic. The mirror and the scope turned out really well. I'm pleased. My dilema is with the eyepieces. I can't find the next eyepiece to fit in to what I already have and I don't understand why. I have my starter scope, a 6" reflector from Orion and 3 eyepieces. The eyepieces are 1.25", 25mm, 17mm and a 10mm Explorer II's from Orion. They cost $28 a piece. My 12.5" scope has a 2" focuser. I bought a 50mm and a 32mm eyepiece from Orion. Optiluxe, $139 and $149. They both work great. The lagoon and swan nebula's looked great, but I wanted more power. Something in the 15 to 20mm range. I looked around and couldn't find that many that are reasonably priced, so I bought a 17mm Lanthanum from Orion. $245. It's a 1.25" that fits a 2" focuser. 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. If a 2" eyepiece in the 15-20mm range is where I should go, please give me suggestions on which one to get. Do I need to spend more money for a good lens? I've thought about this and just can't reason it out. Any help would be most appreciated. PS. Thanks for helping me with the mirror Brent. _______________________________________________ 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
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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