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Old April 15th 18, 12:35 AM posted to sci.astro.amateur
RichA[_6_]
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Default We need new nomenclature

I read a review of the ugly Baader Morpheus eyepieces on cloudynights and
something stuck me. The reviewer used the term, "diffraction rings" (of a star)when describing the view through a 65mm Pentax refractor using the 17mm Morpheus. Problem is, that's 22x on that scope with that eyepiece. So he was describing the intra and extra-focal rings shown when a star is thrown out of focus and not the in-focus diffraction rings seen at powers of 30x per inch and up. We should call the rings formed by out of focus star images something other than diffraction rings since they are definitely not that.