I think it's more relevant to think of "options in the maxed out 1.25 field stop" range instead of "near the 32mm focal length range".
Because you only have access to a 1.25" barrel, you are restricted to a field stop of 27mm and therefore true FOV of 1.2°.
A 32mm plossl is already a well-corrected, light, easy-to-use, and cost effective eyepiece for this 27mm field stop niche. You aren't going to see much of a difference in clarity by upgrading because a 32mm plossl generally doesn't have many defects to be dealt with. That said, I think it's perfectly reasonable to upgrade to a TV 32mm if you want to. I don't have personal experience with that eyepiece, but you could for example buy one used here, evaluate yourself, and then sell it if you don't like it - eating a relatively small cost in that scenario.
The other direction you can go is in other aspects of the eyepiece such as:
Spreading out that TFOV over a wider AFOV (thus zooming in and expanding the picture).
- This will help stars pop more against skyglow and light pollution since star brightness isn't affected by zooming in while diffuse objects (like the light pollution) are dimmed
- The views can be more immersive with a wider AFOV. This is pretty fun!
- The eye placement is harder. I've had little children with very little difficulty in my 32mm plossl (50° AFOV) that really struggle to use my 30UFF (70° AFOV). You'll easily overcome this and it will get easy, but it's different for your guests
- They are heavier and more expensive. Take heavier seriously with a C90 MAK as something like a 13mm Ethos for example has nearly the same TFOV of a 32mm plossl but weighs 1.3lb (28% the weight of your scope!!). That eyepiece would likely require that you jerry-rig a balancing solution to your mount. For reference, a TV 32 plossl is 0.39lb and a Celestron Omni 32mm plossl is 0.34lb.
- After a certain point, it's hard to use these with glasses. Extremely wide AFOV eyepieces necessitate smaller eye relief (it's just geometry). Individual designs vary and eye relief numbers are notoriously unreliable since they measure distance from the glass which may not be the distance from the minimum eyeguard.
- Examples here: Televue 24mm panoptic (full 1.2° TFOV spread across 68° AFOV, 0.5lb), Celestron 15mm Luminos (full 1.2° TFOV spread across 82° AFOV, 0.75lb), Televue 13mm Ethos (1.0° TFOV spread across an insane 100° AFOV, 1.3lb), plenty of others, these were meant to be instructive not specific recommendations.
Better mechanical properties
- Some eyepieces offer screw-up/down eyecups (convenient for sharing between glasses and non-glasses users), rubberized grips, or other benefits
Better light transmission (maybe)
- I haven't personally used them, but some people love brandon and ortho eyepieces for their slight edge in brightness. This often comes at the cost of eye relief (comfort with eyeglasses) and AFOV relative to other options at the same price point
I haven't actually offered any suggestions here (I haven't even used most of the example eyepieces that I cite), but hopefully this can be helpful in better understanding what it means to "upgrade beyond a fully multi-coated 32mm plossl". It's less about strict upgrades and more about tradeoffs and priorities at this point.
Edit - Lastly, I agree with many others that your money is likely better spent elsewhere. Also, I'm well aware it's rather ridiculous to even discuss something like a 13mm Ethos on a C90 Mak but I think it's good to develop a full understanding of the problem and the extremes are useful when trying to understand these things.
Edited by GolgafrinchanB, 22 April 2025 - 07:11 PM.
