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llanitedave
Humble Megalomaniac
   
Reged: 09/26/05
Posts: 12885
Loc: Amargosa Valley, NV, USA
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Re: Strange Results in Eyepiece FOV Comparisons
05/17/08 12:30 PM
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This makes for an interesting discussion. I suppose the barrel distortion in the Hyperion could explain my results. What I'll need to do next is check out the drift at different distances from the center and look for variations.
It's not at all obvious to the casual eye that it's there, and certainly doesn't seem to visually distort any extended features. I'm also curious about what angular magnification distortion might be present in either of the Hyperion or Nagler. From my visual impressions so far, I think I'm willing to put up with a subtle barrel distortion in order to pick up a wider true field of view. I guess it wouldn't be such a good choice for astrometry, though. What surprises me most is how people seem to think that apparent field of view is such an obvious and objective characteristic. It's not for me. Peripheral vision is a funky thing, and in wide field eyepieces, that comes into play at the edge of the field. It's actually hard for me, at times, to see a difference in the apparent surface area of the field between the Hyperion and the Nagler. I have to look closely and move my eye around to confirm that the Nagler is wider.
-------------------- "Since the process of science generates more mysteries than it solves, I predict that we'll never learn everything: and we'll continue to generate new ignorance at the speed of knowledge."
"S.O.E." (Sauron's Other Eye), with 16" Royce conical mirror: A permanent work in progress.
10" Homebuilt dob, old Coulter mirror
Under Construction: The "Eye of Sauron" Observatory!
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