Ethos 13, or ES92 12, or stick with my ES82 14, or ... ?

[scarp15]

15 hours ago, Piero said:

Ethos, Pentax, Delos, APM XWA will all be fine. I find that that is more about loyalty to a certain brand, ergonomics, AFOV, rather than delivered quality.

 

Perhaps loyalty but more so becoming parfocal, such as interchanging amongt Delos and DeLite focal lengths. 

[Don Pensack]

16 hours ago, HollyHound said:

I’d agree with that Don 👍

I’ve tested the Morpheus 14, XW14, Delos 14 and DeLite 13 in both an 80mm f/10 refractor (focal length 800mm) and 10” f/5 dob with ParaCorr 2 (focal length 1460mm).

Field curvature was very noticeable with the Morpheus and slightly more so with the XW,  but not visible with the other two, when used in the refractor.

Field curvature was (barely) noticeable with the Morpheus, again slightly more so with the XW, and not visible with the other two, when used in the dob.

I’ve just bought and tested (once) an Ethos 13 in the dob, and no field curvature is visible at all.

I find coma very noticeable with all these eyepieces if the ParaCorr is not used, so that stays in the dob for all sessions, but I’m aware some don’t find it objectionable.

The Delos 14 is my most used eyepiece in the dob for DSOs, but as the Ethos is the same quality with a wider FoV, it will likely replace it for most sessions. I have sold the Morpheus and selling the DeLite, but retaining the XW as it fits my XW set and still gives a superb relaxed central field view 😊

And my own dob has an 1826mm focal length, so is even flatter.  Since the longer the focal length, the less FC is seen in the 14mm Morpheus, does that mean its focal plane is completely flat?

Because if focal plane | is mated with (  you get ( in the image.

More likely, it's focal plane is curved slightly in the same direction as the scope's so ( + ( = < (really strongly curved)

And as the focal length gets longer, the 2nd curve gets flatter, reducing the impact of the ( in the eyepiece.

We all have the ability to tolerate a very slight FC, but not when the scope compounds the problem.

That's the issue, for instance, with the 14mm Pentax XW, which I also see as fine in my dob, yet that eyepiece has a ton of reviews describing FC in the eyepiece.

All from telescopes with more strongly curved focal planes.

 

[Louis D]

17 hours ago, HollyHound said:

Where they do differ is immersion... with the Delos, the field edge is visible, but with the Ethos, it isn’t of course and so it really does feel like you’re “floating in space”

You have to watch out for that floating in space feeling.  It can be unnerving 🤣:

 

Edited February 22, 2021 by Louis D

[rkelley8493]

On 20/02/2021 at 03:58, Size9Hex said:

Hi everyone,

I would welcome your experience and advice on an eyepiece decision please:

In short, which eyepiece for my "lives in the focuser" DSO sessions? Ethos 13mm, ES92 12mm or should I stick with my existing ES82 14mm or something else? Main scope is a 10" f4.7. I'm wondering if one the alternatives might give me a more comfortable view with more of the field visible.

Slightly more: I realise I'm lucky to have an ES82 14mm. It's a great eyepiece that I've been using for years. Mid power DSO viewing, high quality view, wide enough for star hopping, but deep enough for great views of the showpiece objects - just thoroughly enjoyable observing that isn't pushing equipment or observer or sky quality to the limits! I'm only questioning the ES82 14mm because of the ergonomics and because if there was a single eyepiece I really wanted to optimise, it would be the one in this niche. The ergonomics of the ES14mm are such that I can either view comfortably with about 60-65 degrees visible or I go almost within eyelid touching distance to get about 75 degrees with the field stop needing a slight head turn in either case. The latter isn't uncomfortable, but it could be more comfortable...! The Ethos or ES92 are of interest if the the wide field is more accessible/comfortable. Seems odd, but I briefly dwelled on a Delite given how much time I spend at ~60 degree distance from the ES82 anyway! 🙄 . I love those big wide starfield views at this focal length though. Do other ranges open up the accessible AFOV?

Interested in any and every experience and opinion on it. 🙂

Thanks!

Here's a visual between the two, pictured below..

I had a chance to compare them, and the last thing that crossed my mind was the difference in FOV. They're both equally excellent performers, but the presentation is completely different. The whole 92º field can fit on the huge eye lens of the ES. The image just seems to float above it.

The Ethos felt more like a porthole experience, like you are looking into a window to outer space. Other users have found it easier to view through, i.e. more consistent exit pupil.

So I guess depends on your level of experience [depends on your style as well.. I prefer long eye relief EP's]. With practice you learn how to adapt your eye to the exit pupil in long eye relief oculars. Ones not familiar with LER eyepieces may have some trouble [like kids or others you may share with], but like any sport or hobby, practice improves your abilities.

One thing to mention though, and it has nothing to do with the views.. The 12 ES 92º is much more massive than the 13 Ethos, almost twice as much. The 12/92º weighs 1017g vs 590g for the 13E. This could be an issue with smaller style manually tracked mounts. Just something to consider..

Edited May 4, 2021 by rkelley8493

[Size9Hex]

Thank you @rkelley8493, that's a really helpful perspective on it. That top lens in the ES92 12mm is immense!

I find it interesting that you haven't equated longer eye relief with being easier to use. I had assumed, probably wrongly in retrospect, that more eye relief in the ES92 would automatically be more comfortable. And in fact, I should have known better. A couple of long focal length EPs I've used have very generous eye relief, but it extends further out than rubber eye cup - and they took quite a bit of getting used to. One of these was absolutely transformed by fitting an extended eye cup. Other long eye relief eye pieces I've used have the eye cup absolutely spot on, and have been brilliant.

I think you've hit on something of importance in saying the presentation is completely different. I'll have to compare a few of my existing porthole / long eye relief eyepieces again to see if it helps the decision, or hopefully find a chance to look through an Ethos/ES92 first. There was a 13mm Ethos in the for sale section recently which I perhaps should have taken a punt on.

Thanks again. 👍

[John]

19 minutes ago, Size9Hex said:

...I find it interesting that you haven't equated longer eye relief with being easier to use. I had assumed, probably wrongly in retrospect, that more eye relief in the ES92 would automatically be more comfortable. And in fact, I should have known better. A couple of long focal length EPs I've used have very generous eye relief, but it extends further out than rubber eye cup - and they took quite a bit of getting used to. One of these was absolutely transformed by fitting an extended eye cup. Other long eye relief eye pieces I've used have the eye cup absolutely spot on, and have been brilliant....

.

You raise a very good point. From my experience with the 17mm and 12mm ES 92's I think it would be worth having a look through them yourself if possible before committing. I have found the eye positioning quite challenging on the 17mm but I am now getting the hang of it but the 12mm I just could not get used to so I let that one go to a new home.

I can see for the glasses wearer that the eye relief of these would be very useful but it is almost too much of a good thing for the non-glasses wearer (like me) perhaps ?

Optically they are excellent though.

 

 

[Space Hopper]

This is my midrange widefield.

I'm not sure, but i've read somewhere they've been discontinued ?

It impresses me every time i use it.

 

Edited May 6, 2021 by Space Hopper

[John]

1 hour ago, Space Hopper said:

This is my midrange widefield.

I'm not sure, but i've read somewhere they've been discontinued ?

It impresses me every time i use it.

 

Sadly I believe they are no longer in production. They do have a wonderful reputation though

My mid-range is a 13mm Ethos and a 14mm Delos.

 

[Louis D]

2 hours ago, John said:

Sadly I believe they are no longer in production. They do have a wonderful reputation though

My mid-range is a 13mm Ethos and a 14mm Delos.

 

Sadly, nearly the whole company closed up shop.

[Space Hopper]

That is a shame ; i'm sorry to hear that.

I know they are no longer listed on the 'Okularum' website (Copenhagen, Denmark)

I purchased a pair of them last autumn for the binoviewer, but sold one of them after trying them out.

The one i have left is definitely a keeper !!