Anyway, if you were seeking a general-purpose, portable, high-quality visual-only instrument for planets and
Ideally, the
Hmm. Interestingly, the Vixen VMC260L boasts the largest
I don't think that anyone was suggesting that you didn't know that the μ-210 was advertised as a non-corrected Dall-Kirkham. What I was suggesting is that one explanation for the great reviews it gets is that Takahashi is tweaking the mirror surfaces slightly with a higher order curve. That's the only way it could be better than a classical Cassegrain of equalAntennaGuy wrote: ↑Tue Jul 14, 2020 10:59 pmHmm. Interestingly, the Vixen VMC260L boasts the largestaperture area/weight ratio among any of the OTAs I've considered:
(and yes, sorry, I know the Mewlon 210 is actually a non-corrected Dall-Kirkham).
Oops, my comment here was evidently misleading! I was actually referring to my own error in the table that I just posted! I was not complaining or referring to your remarks (which, by the way, have been very educational)notFritzArgelander wrote: ↑Tue Jul 14, 2020 11:20 pmI don't think that anyone was suggesting that you didn't know that the μ-210 was advertised as a non-corrected Dall-Kirkham. What I was suggesting is that one explanation for the great reviews it gets is that Takahashi is tweaking the mirror surfaces slightly with a higher order curve. That's the only way it could be better than a classical Cassegrain of equalAntennaGuy wrote: ↑Tue Jul 14, 2020 10:59 pmHmm. Interestingly, the Vixen VMC260L boasts the largestaperture area/weight ratio among any of the OTAs I've considered:
(and yes, sorry, I know the Mewlon 210 is actually a non-corrected Dall-Kirkham).
aperture and secondary magnification factor.
It's certainly understood to have no refractive corrector elements. But the Dall-Kirkham design has only quadratic (conic section) curves and if there is a higher order curve on a mirror surface then there is a semantic quibble about whether it is still uncorrected.
Ah, it's a relief to know I've not offended. Thanks.AntennaGuy wrote: ↑Tue Jul 14, 2020 11:27 pmOops, my comment here was evidently misleading! I was actually referring to my own error in the table that I just posted! I was not complaining or referring to your remarks (which, by the way, have been very educational)notFritzArgelander wrote: ↑Tue Jul 14, 2020 11:20 pmI don't think that anyone was suggesting that you didn't know that the μ-210 was advertised as a non-corrected Dall-Kirkham. What I was suggesting is that one explanation for the great reviews it gets is that Takahashi is tweaking the mirror surfaces slightly with a higher order curve. That's the only way it could be better than a classical Cassegrain of equalAntennaGuy wrote: ↑Tue Jul 14, 2020 10:59 pm
Hmm. Interestingly, the Vixen VMC260L boasts the largest aperture area/weight ratio among any of the OTAs I've considered:
(and yes, sorry, I know the Mewlon 210 is actually a non-corrected Dall-Kirkham).
aperture and secondary magnification factor.
It's certainly understood to have no refractive corrector elements. But the Dall-Kirkham design has only quadratic (conic section) curves and if there is a higher order curve on a mirror surface then there is a semantic quibble about whether it is still uncorrected.
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