10-01-2021, 11:23 AM
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Registered User
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Join Date: Feb 2006
Location: Sydney
Posts: 17,907
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Thanks Don.
Greg
Quote:
Originally Posted by Don Pensack
The APM 12.5mm has one more element than the Docter, a slightly larger field stop, a millimeter less eye relief, so not exactly a clone.
That being said, distortion characteristics are almost the same, with angular magnification distortion (rolling ball or globe distortion) predominating, unlike most astronomical eyepieces. It is usable with glasses.
It is quite sharp but also has a bit of edge of field brightening (EOFB).
No noticeable spherical aberration of the exit pupil (SAEP).
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Quote:
Originally Posted by Don Pensack
No, not better than the 12.5mm Morpheus, just wider.
And if it's more expensive than a Nagler, and you don't need to wear glasses at that focal length, forget it. It is not the equal of the Docter/Noblex.
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