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Posts Made By: henry link

February 23, 2010 02:23 PM Forum: Global Warming - REAL or NOT

This Forum

Posted By henry link

The never ending story of this forum:

http://www.npr.org/templates/story/story.php?storyId=124008307

Also, thank you, Dean Rowe, for posts that consistently rise above the noise.

July 13, 2006 07:46 AM Forum: Eyepieces

Re: Ye old Pan 24mm

Posted By henry link

I see the same distortion in my 22mm and 19mm Panoptics and in my 13mm Nagler. In fact I've seen it in every TV Nagler, Wide Field and Panoptic eyepiece since the first ones I bought twenty years ago. I think the worst side effect from this distortion is loss of real field. The increasing magnification and distortion of shapes toward the edge causes around a 10% loss of real field compared to what a distortion free eyepiece with the same apparent field would yield. Naglers produce about the same real field as 73-75 degree distortion free eyepieces and Panoptics' real fields equal about 61-63 degree distortion free eyepieces.

November 11, 2009 08:36 AM Forum: Refractors

Zeiss 85mm Diascope--impressive!

Posted By henry link

Doug,

You were lucky to get a Diascope that good. I've tested eight of them and only one star tested about as well a Tak SKY90. Two were outright lemons with the usual spotting scope defects; coma, astigmatism, pinched optics.

Can I ask where you found a refurb for such a good price?

Henry Link