Telescope Reviews: To Ethos, or not to Ethos...

I have both pairs:
31T5 & 26T5 Naglers
13 & 8 Ethos

If the 13Ethos proves impressively pleasing to you, the value of also adding the 8E at your earliest feasible opportunity will immediately become blindingly, almost painfully obvious.

The value of having both 31T5 and 26T5 is admittedly much less obvious - and while the exit pupil reasoning given by Tom T. is the rock-solid core of the technical explaination behind there being worthwhile reasons, nonetheless it's easier to appreciate in direct practical terms.

The 26T5 works better in a wider variety of situations (read: including light polluted suburban environments) because the higher magnification/smaller exit pupil produce a darker, more contrasty background. The sky can seem little darker than naked-eye in the 31T5 under typical suburban moderate light-polluted conditions, whereas the 26T5 will be significantly darker/more contrasty in such an environment, by comparison. The panoromic true field of view is one of the most impressively generous available, EXCEPT when compared back-to-back with the 31T5 in a more favorable viewing environment to the latter (read: darker skies).

BUT: In a darker-sky environment (even ones with some mild degree of light pollution), the comparative disadvantages caused by the larger exit pupil/lower mag 31T5 disappear - and what you then have is the most magnificent widefield panoromic eyepiece on the planet. A raw numerical TFOV comparison between the 31T5 and 26T5 (10% greater radius and 44%greater area in the 31T5) fails to convey just how much more visually immersive and broad the panorama in a 31T5 seems over a 26T5 - enough that whenever conditions are appropriate, I'll reach for the 31T5 first EVERY time.

However, most of us who have this particular pair (26 & 31) probably come to it either by having the 26 first and having a later opportunity to pick up the 31 without having to finance it by sale of the 26, OR else have the 31 first and come across a opportunity-you-can't-refuse sort of bargain on a 26. If you don't have either yet, the 31T5 and 22T4 might make a better-spaced pairing, while accomplishing much the same purpose as the 26/31 pairing. For many of us who already have the 26/31 pairing, however it works well enough to not be worth the trouble of selling the 26 and then finding a 22 used (or the risk we might turn out to not like the 22 as much as the 26 we already know).

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Chris M., aka "First Sight"
Orion XT12i Dob with Moonlite CR-2 focuser
WO Megrez 90 refractor on UniStar Light mount
Nikon 10x50 Binoculars