Am jumping on to the end of this thread. As it is pretty long, my apologies in advance if I'm covering old ground. Just don't feel like trying to filter through all the previous comments.
Am bringing this comment over from the OOTW thread in which Alvin referred to "high-glass eyepieces" (I'd never heard that description before). Which I now understand to mean basically premium wide-field EPs. Which is fine, I get it.
But am now curious if anyone's done the test comparing the Delos line to various low-glass alternatives.
Personally, I own all the Delos line except for the 17.3 (can't bring myself to part with my 17 T4 Nagler) plus the entire line of UO Orthos (volcano tops). I don't use the Orthos bare. I have a couple removable eye-cups that I use with them. Really helps with eye positioning and blocking local glare.
I never did a true A-B comparison between Naglers and Orthos. But in practice, there were many times I'd be digging on some HCG and be struggling to see something that should be there in a Nagler and would switch to an Ortho of equal FL and then be able to resolve the troublesome member. A prime example I do remember was going after UGC 4171 during TSP 2010 (part of Larry Mitchell's Flat Galaxies list). Had been using 9 and 5mm Naglers with no joy. Put in a borrowed 7 Ortho and it popped right out (looked like a field star developed diffraction spikes, but only along one axis). The 5mm Ortho allowed me to split the galaxy off of the star. That was pretty much my experience with Orthos v. Naglers. That was also the point that I really started looking for the "Nagler Alternative". That ended up being the Delos (couldn't bring myself to drop the big bucks on the Ethos but that's a whole other conversation).
I think the benefit of going to Orthos (or any other low-glass alternative) is two fold. The first is obviously less glass. But the other (and the one nobody talks about) is the tight field. Personally I find that my focus wanders a bit when using a wide-field EP. That soda-straw field of an Ortho really focuses me. My attention doesn't wander. But to really take advantage of that, tracking is absolutely necessary.
My experience with the Delos has been much more satisfying than with the Naglers. I feel like I'm seeing what I should be seeing when observing HCGs. So I haven't been using my Orthos. I think I'll have to do some testing this coming dark window. I wish I'd thought to go after UGC 4171 while in Pettigrew this past February. That'll make a nice test for the Delos.
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