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  #21  
Old 27-04-2006, 07:56 PM
ausastronomer (John Bambury)
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Quote:
Originally Posted by Dave47tuc
Well I was able to observe again last night for 3 hours.
Lucky Man !!! I made friends with a bottle of Bulleit Bourbon and enemies with my wife. Observing wasn't an option, wrestling was

Quote:
Originally Posted by Dave47tuc
The Pentax’s again excelled. I just can’t believe how good they are. In my Mak, just so sharp. I screwed my eyecup up a bit more and found that more comfortable to use. IMO these pentax’s for me are a lot better than naglers..
Every time you come back from an observing session with these eyepieces for some time still to come, little things are going to stick in your mind, where they continue to show you little subleties, where they excel and grow on you. They continued to grow on me for 2 years. They just got nicer and nicer, as I continued to appreciate how good they were.

Someone else mentioned the minor field curvature in the 14mm Pentax XW. I am prepared to forgive it this little sin for everything else that it gets right and does exceptionally well. It does not have quite as flat a field as the 13mm Nagler T6 but it gives it a bit of a shakedown in most other critical aspects IMO, particularly on axis sharpness, light transmission and contrast. Funnily enough, I read a comparison today on Astromart, albeit an old one, where the reviewer compared the 13mm NT6 and the 14mm Pentax XW. He rated the Nagler sharper on axis than the Pentax. The only conclusion I could draw from his review is that I don't want to end up with his eyesight

In respect to the longer focal length 20mm range, I rate the 21mm Denkmeier as the pick very closely followed by the 22mm Vixen LVW then the 24mm Panoptic.

CS-John B
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  #22  
Old 13-05-2006, 04:20 PM
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Dave47tuc (David)
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Well it’s cloudy and not much happing at home.
So I have been browsing the net as we do on scope stuff and thought I would stay on the Pentax bandwagon and found a nice read why you should buy these wonderful eyepieces.

http://www.cloudynights.com/item.php?item_id=1353

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  #23  
Old 13-05-2006, 05:50 PM
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janoskiss (Steve H)
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I read that review before. The reviewer is perhaps a little over-enthusiastic. He claims that "Pentax has stated that visible light transmission is 98%". That would be excellent even for a plossl or ortho. Pentax's own figures give a peak transmission between 95 & 96% (depending on focal length, at yellow-green 550nm), dropping off to about 90% at the red and violet ends of the spectrum: http://www.pentax.co.jp/japan/tech/xo-xw/63.html

Not saying that this means the eyepieces are no good (and indeed the figures are very impressive even if they are not an impossible 98%!), but one exaggerated claim like that can diminish the credibility of a whole review.
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