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

[Size9Hex]

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!

[Louis D]

In my experience, viewing comfort equates to eye relief.  If you have to cram your eye into a recessed eye cup to take in the view, how can you relax?

The Ethos all advertise 15mm of eye relief, but due to ergonomic factors, it's probably closer to 12mm to 13mm.  Most folks find them comfortable to use without eyeglasses, but the view isn't as readily accessible as longer eye relief eyepieces.

The ES-92 eyepieces have 20mm of advertised eye relief, but I've measured them at 17mm of usable eye relief.  This is just enough to use them comfortably with eyeglasses.  Many folks find it too much without eyeglasses, but others find the view more accessible and immersive without eyeglasses than the Ethos due to the longer eye relief.  For me, with eyeglasses, I can take in the whole field at once without having to crane my head to the side.  I've overhead folks who look into them exclaim "My God, it's full of stars!", and so it is.  The flat, aberration free field also helps to contribute to this experience.

[Louis D]

If you're content with a 72 to 76 degree field, the TV Delos and Baader Morpheus might suit you better.  They all have ample eye relief and an easy to take in view.

[John]

3 hours ago, Louis D said:

The ES-92 eyepieces have 20mm of advertised eye relief, but I've measured them at 17mm of usable eye relief.  This is just enough to use them comfortably with eyeglasses.  Many folks find it too much without eyeglasses....

I'm one of those people, unfortunately

I still have the ES 17mm / 92 though and that is better in this respect for me as a non-glasses wearer. The optical quality and immersiveness of the ES 92's is very impressive. They are pretty much as good as my Ethos eyepieces. The best ES eyepieces that I have used.

The downsides are that they are £400+ eyepieces currently and weigh a LOT !

With an F/4.7 scope though, coma is going to be an issue, unless @Size9Hex is planning on using a coma corrector ?

 

[Paul73]

3 hours ago, Louis D said:

If you're content with a 72 to 76 degree field, the TV Delos and Baader Morpheus might suit you better.  They all have ample eye relief and an easy to take in view.

I went from the ES82° to the 14mm Delos and have been very happy with the move. However.... you can see the lovely crisp field stop due to the long eye relief. The Ethos will give the “floating in space” feeling which encourages you to get really close in to explore the view. I haven’t tried the ES92° range.

Paul

[scarp15]

I think as Paul says, 14 or 12mm Delos could be a strong contender at that focal length range. I only currently have a 10mm and have owned a 6mm, each very comfortable eye placement, as mentioned crisp image right up to the field stop. 

[Don Pensack]

I love the 14mm Delos, and almost bought one.  But I loved the 14mm Morpheus more.  Both are quite usable with glasses.

I use a coma corrector on my 12.5", so it's f/5.75 and has a fairly flat focal plane, so I don't see any issues with the 14mm Morpheus,

Some people with much shorter focal lengths who do not use a coma corrector have had issues with FC in the 14mm.

As I read people's remarks, the dividing line appears to be about 1200mm, with longer focal lengths giving it great reviews.

[Size9Hex]

Thank you Louis, John, Paul, Iain and Don. It’s absolutely brilliant to be able to draw on such experience and advice.

@John I don’t have a coma corrector, and perhaps naively, hadn’t thought about it in association with going with an even wider eyepiece. I’ve not found coma bothersome in my 24mm which has a lovely accessible 82 degrees - although in this EP, I’m usually nebula hunting which perhaps doesn’t draw attention to coma in the way other targets might. I suppose if I study the coma at the edge of the 14mm more critically I might get a better idea of how it would be. When you say coma will be an issue, would you expect a corrector to be essential at 92 to 100 degrees?

Thanks for the extra ideas on the Delos and Morpheus which I hadn’t really considered. Look like they would definitely tick the comfort box. Interested to know whether folks still experience the "It’s full of stars!’ view on these - I love your quote @Louis D! This is what I’m hoping I might be able to get in this eyepiece choice - it’s my go-to for most of the showpiece open clusters for example. That’s really good feedback on the usable eye relief on the ES92 too - thanks. 👍

Would love to hear any other perspectives too. Thanks again! 🙂

[John]

I don't use a coma corrector either but my 12 inch dob is F/5.3. Coma is there but, personally, I don't find it intrusive even with 100 / 110 degree eyepieces.

Others do feel that is an issue though and use a CC even with F/6 scopes.

I've not owned an F/4.7 for a long time and when I did I didn't have any 100 degree eyepieces so I don't know how intrusive coma will be with such wide angled eyepieces.

I really like that "endless pool of stars" effect as well which is why I have always sought very wide field eyepieces. It's not everyone's "thing" though I appreciate that.

The ES 17mm 92 is probably the most immersive eyepiece that I have currently even though some of my others have an even larger apparent field. I guess it must be a combination of the massive eye lens AND the eye relief AND the 92 degree field that does it.

 

 

Edited February 20, 2021 by John

[rl]

As others have commented, the ES92 17 is a truly stonking lump of glass, IMHO better corrected than any of the ES100 range I have owned or looked through. I've detected Cassini's division with telescopes of smaller aperture than the eye lens on the ES17.

Depending on your observing environment, the excellent eye relief can let in quite a lot of stray light if you happen to be afflicted by local street lighting or houses. I used to think that the Ethos was a bit tight on eye relief and wished for a bit more, but having owned and used both in a light polluted environment I think the Ethos really has it just about right providing you don't need glasses. Raising the eye cup on the ES helps, but it's not a complete solution. 

And if you are observing with glasses, you may find that the 92 degree field gets cropped top and bottom so you don't get the full benefit of that magnificent field. 

Edited February 20, 2021 by rl

[Arneb]

I could wax lyrical about both of the ES92s. For me, acquiring them was one of the best decisions I have made equipment wise. The 17mm, as has already been mentioned, is particularly immersive and I love it's rendering. I cannot fault the 12mm either - just the other night I spent a very enjoyable 'grab and go' session with the 12mm and np101. So much so I had a grin on my face the entire time - I couldn't stop myself returning to M42 and M45 to bathe in the views.

I'm not a spectacle wearer and find them incredibly comfortable to use (eyecups up). I can take in the full FOV without issue. Strangely I struggled with finding a comfortable eye position with the Morpheus I have tried and which I moved on - I'm probably the only one who has though!🤔 Seems the ES92s are the glass slippers to this Cinderella's eye sockets! 😉

 

[John]

I've owned and used Ethos eyepieces since they were launched. I'm not a glasses wearer.

I found the ES 92's harder to get used to re: eye positioning. I couldn't get on with the 12mm even after several sessions with it, so I let that one go in favour of the Ethos 13 which I'd owned for a few years. I like to have my eye nestled gently into the rubber eye cup to keep out stray light but with the 12mm ES 92 I could not do that without seeing black outs and holding my eye a few mm back from the eye cup I find less than relaxing as well.

The 17mm 92 is not as extreme in terms of eye position so I am gradually getting used to it. Its still not ideal for me though and I still find the Ethos the most comfortable though. 17mm is not a focal length that I use often (I tend to skip straight from the 21mm to the 13mm Ethos) so it is possible that I would let the ES 17 / 92 do at some point, despite it's excellent optical performance. I do also have the Delos 17.3mm in the 1.25 inch case and the 17mm ES 92 does take up a lot of "real estate" in the 2 inch eyepiece case !

 

I do think that the ES 92's are excellent eyepieces but for the non-glasses wearer, they can, for some, pose some challenges re: eye positioning. This may be down to some extent to facial ergonomics as well as the eyepiece characteristics.

I wanted to try them though, after reading such a lot about them so I'm glad to have had the chance to use both focal lengths in the range

Edited February 21, 2021 by John

[michael.h.f.wilkinson]

I have the ES 12 mm 92 deg EP, and it is brilliant. I also have a 14 mm Delos, which is a lot lighter, just as sharp, and perhaps a shade more comfortable, but I find the ES 12 mm 92 deg absolutely superb. It definitely beats the Tele-Vue Nagler 12 mm Type 4 for viewing comfort (and FOV), and even has a slight edge in terms of image quality. It is rather a beast in terms of sheer size:

For reference: that is an 80 mm F/6 refractor

[Piero]

If I were in the market for a medium power eyepiece for a F4.7 dobson, I would look for something around 10mm focal length, rather than 13-14mm. That would be closer to a 2mm exit pupil. 

With this in mind, options could be 10mm Pentax XW (<<== what I would get, but I prefer ~70 to 100 deg AFOV), 10mm Delos, 10mm Ethos, and 9mm APM UWA 100 deg.

If you add a TV paracorr2, the resulting exit pupil will be around ~1.7mm which is still nice and very usable for a medium power eyepiece.

[Size9Hex]

Thank you everyone for all of the latest replies and help.

@michael.h.f.wilkinson Do you mind me asking whether you wear glasses with the ES92 please? Trying to get a sense for how many of the ES92 fans are non-glasses wearers.

@Piero Thanks that’s an interesting point you make. I wondered about a 10mm Ethos. For me, it feels like this focal length is around the boundary between two observing styles. Longer than this is big wide relaxing and enjoying the view and less than this is getting into coaxing out tricky detail - and generally small detail, not requiring big fields of view. My current closest EP in this range is an ES82 8.8mm. It’s not a hard boundary and it’s a bit of a generalisation though, and longer term I’m not sure whether I see this focal length being super wide or not. Agree that the 10mm Pentax would be stonking though! 🙂 A 10mm (assuming I sell the 14mm) would give me a big gap down from the 24mm. I’ll have a look at the true FOV though - it feels important that this EP will be wide enough for star hopping to ensure it’s the relaxing low faff eyepiece that lives in the focuser. Thanks for your advice on it! 👍

[Piero]

3 minutes ago, Size9Hex said:

Thank you everyone for all of the latest replies and help.

@michael.h.f.wilkinson Do you mind me asking whether you wear glasses with the ES92 please? Trying to get a sense for how many of the ES92 fans are non-glasses wearers.

@Piero Thanks that’s an interesting point you make. I wondered about a 10mm Ethos. For me, it feels like this focal length is around the boundary between two observing styles. Longer than this is big wide relaxing and enjoying the view and less than this is getting into coaxing out tricky detail - and generally small detail, not requiring big fields of view. My current closest EP in this range is an ES82 8.8mm. It’s not a hard boundary and it’s a bit of a generalisation though, and longer term I’m not sure whether I see this focal length being super wide or not. Agree that the 10mm Pentax would be stonking though! 🙂 A 10mm (assuming I sell the 14mm) would give me a big gap down from the 24mm. I’ll have a look at the true FOV though - it feels important that this EP will be wide enough for star hopping to ensure it’s the relaxing low faff eyepiece that lives in the focuser. Thanks for your advice on it! 👍

 

It can be hard to advice and choose because the existing set should also be considered. I was not aware that you had an 8.8mm ep. If you plan to keep it and use it with this dobson, a 10mm can be redundant. Another option is to use the 8.8mm ep with another scope (e.g. refractor?). A third option is to sell it. These decisions are rather personal though.

Coming back to your reply, again, people can have different observing styles. At 1200mm focal length, to me the 10-14mm does not give a proper boost in magnification for observing small details. I still feel my docter 12.5mm like a panoramic eyepiece in my 12" F6 dobson plus paracorr2 (~2m focal length).

Have you ever looked through a large eyepiece with 100 deg fov? It might be that you don't like the extra weight or the UWA experience. Have you considered to get one in the second hand market first? With this in mind, you could make a choice of shifting your eyepiece collection towards one range or another. 

[Littleguy80]

With my 10” F4.7 dob, I’ve been going through my own debates on these focal lengths over the past few months. Originally I had a 13mm and 9mm APM HDC. 100 degree eyepieces felt like the way to go. What I could never escape from was that my orthos gave better contrast and sharpness than the APM’s. In the end, I settled on sacrificing FOV for image quality. The 9mm APM was replaced with a 10mm Delos. When observing, I found that I was regularly skipping the 13mm and going straight to the 9mm. As Piero said, the 2mm exit pupil is the place to be for DSO’s. In the last couple of weeks, I’ve replaced the APM 13mm with a Docter 12.5mm which also Barlows nicely with the Baader VIP to fill the gap between the 10mm Delos and 5mm Pentax XW. 

In terms of real world performance, my 9mm Ortho (BGO) shows 4 cores in Stephan’s quintet. The 10mm Delos is a shade behind the Ortho but will still show the same 4 cores. I was never able to see the Quintet with the APM. 100 degree eyepieces are great, my 20mm APM is a keeper, but they are a compromise. I’ve not tried an Ethos but suspect that even they sit behind the Delos. To make your decision it’s really a question of what you value most and what you’re prepared to sacrifice in your observing...and bank balance  

[michael.h.f.wilkinson]

1 hour ago, Size9Hex said:

Thank you everyone for all of the latest replies and help.

@michael.h.f.wilkinson Do you mind me asking whether you wear glasses with the ES92 please? Trying to get a sense for how many of the ES92 fans are non-glasses wearers.

 

I do wear glasses when observing.

[Size9Hex]

2 hours ago, Piero said:

Have you ever looked through a large eyepiece with 100 deg fov? It might be that you don't like the extra weight or the UWA experience. Have you considered to get one in the second hand market first? With this in mind, you could make a choice of shifting your eyepiece collection towards one range or another. 

Thank you again Piero, useful perspective on it. Apologies I didn’t put the question in the context of my existing eyepieces originally - although I view these as somewhat fluid, as viewing personal preferences and observing styles become clearer or change over the years... and finances allowing of course.

Sadly I’ve never tried a 100 degree eyepiece. My largest is the 82 degree 24mm at almost 900g. You make a good point. I was pretty shocked when I first saw the size and heft of it, although I’m very happy it now. I’m not sure when (or if!) I might replace the 14mm yet. Short of a lottery win, it might be one for when the summer Milky Way returns, which would give me time to look second hand. Hopefully the world will be in a better place by then too, with more chance to share the views with others. 🙂

[John]

2 hours ago, Littleguy80 said:

With my 10” F4.7 dob, I’ve been going through my own debates on these focal lengths over the past few months. Originally I had a 13mm and 9mm APM HDC. 100 degree eyepieces felt like the way to go. What I could never escape from was that my orthos gave better contrast and sharpness than the APM’s. In the end, I settled on sacrificing FOV for image quality. The 9mm APM was replaced with a 10mm Delos. When observing, I found that I was regularly skipping the 13mm and going straight to the 9mm. As Piero said, the 2mm exit pupil is the place to be for DSO’s. In the last couple of weeks, I’ve replaced the APM 13mm with a Docter 12.5mm which also Barlows nicely with the Baader VIP to fill the gap between the 10mm Delos and 5mm Pentax XW. 

In terms of real world performance, my 9mm Ortho (BGO) shows 4 cores in Stephan’s quintet. The 10mm Delos is a shade behind the Ortho but will still show the same 4 cores. I was never able to see the Quintet with the APM. 100 degree eyepieces are great, my 20mm APM is a keeper, but they are a compromise. I’ve not tried an Ethos but suspect that even they sit behind the Delos. To make your decision it’s really a question of what you value most and what you’re prepared to sacrifice in your observing...and bank balance  

Some folks who observe in the US desert with very big dobs have posted some very interesting comparisons on eyepiece effectiveness over the years. Their findings seem to be that for small and faint galaxies, quality orthos are the very best (Zeiss ZAO in their case) followed (quite closely) by the 10mm Baader Classic Ortho and then the 10mm Delos and Ethos. They rate all these eyepieces but when the chips are down, they could see some performance differences on very challenging targets. They had similar results in the 6mm focal length.

Here is their website. It's well worth exploring:

http://www.faintfuzzies.com/

 

 

[Size9Hex]

2 hours ago, Littleguy80 said:

With my 10” F4.7 dob, I’ve been going through my own debates on these focal lengths over the past few months. Originally I had a 13mm and 9mm APM HDC. 100 degree eyepieces felt like the way to go. What I could never escape from was that my orthos gave better contrast and sharpness than the APM’s. In the end, I settled on sacrificing FOV for image quality. The 9mm APM was replaced with a 10mm Delos. When observing, I found that I was regularly skipping the 13mm and going straight to the 9mm. As Piero said, the 2mm exit pupil is the place to be for DSO’s. In the last couple of weeks, I’ve replaced the APM 13mm with a Docter 12.5mm which also Barlows nicely with the Baader VIP to fill the gap between the 10mm Delos and 5mm Pentax XW. 

In terms of real world performance, my 9mm Ortho (BGO) shows 4 cores in Stephan’s quintet. The 10mm Delos is a shade behind the Ortho but will still show the same 4 cores. I was never able to see the Quintet with the APM. 100 degree eyepieces are great, my 20mm APM is a keeper, but they are a compromise. I’ve not tried an Ethos but suspect that even they sit behind the Delos. To make your decision it’s really a question of what you value most and what you’re prepared to sacrifice in your observing...and bank balance  

Thank you Neil, that’s a great perspective on it.

I have a similar experience with orthos at shortly focal lengths. They just squeak out that extra bit of texture on Mars, pull out slightly fainter/closer double stars, and scatter less light. Made me realise I value optical purity at short focal lengths more than wide fields. I didn’t get on with a longer focal length ortho though - even though it was a lot more comfortable to use than the short ortho, I think I value wider fields more at longer focal lengths. But around 10mm (give or take) I think there’s a transition.

Overall, thanks to everyone who has responded. Lots of personal preference involved, which is nice to see. 🙂

[Piero]

23 minutes ago, Size9Hex said:

Thank you again Piero, useful perspective on it. Apologies I didn’t put the question in the context of my existing eyepieces originally - although I view these as somewhat fluid, as viewing personal preferences and observing styles become clearer or change over the years... and finances allowing of course.

Sadly I’ve never tried a 100 degree eyepiece. My largest is the 82 degree 24mm at almost 900g. You make a good point. I was pretty shocked when I first saw the size and heft of it, although I’m very happy it now. I’m not sure when (or if!) I might replace the 14mm yet. Short of a lottery win, it might be one for when the summer Milky Way returns, which would give me time to look second hand. Hopefully the world will be in a better place by then too, with more chance to share the views with others. 🙂

A 24mm 82 is a nice low power ep using that f-ratio. . Again, choosing eyepieces is really a personal matter. Personally, I would prefer a bigger "jump" and go from 24mm to 10mm. Then, I would choose a 6mm for a "zoom-in". Later on, something like a 4.7mm-4mm for close-up (e.g. moons, planetary nebulae, small galaxies). Said this, those 3 eyepieces (24mm, 10mm, and 6mm) would stay in the focuser most of the time. Few eyepieces means less swapping and less financial drain. 

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.

[John]

24 minutes ago, John said:

Some folks who observe in the US desert with very big dobs have posted some very interesting comparisons on eyepiece effectiveness over the years. Their findings seem to be that for small and faint galaxies, quality orthos are the very best (Zeiss ZAO in their case) followed (quite closely) by the 10mm Baader Classic Ortho and then the 10mm Delos and Ethos. They rate all these eyepieces but when the chips are down, they could see some performance differences on very challenging targets. They had similar results in the 6mm focal length.

Here is their website. It's well worth exploring:

http://www.faintfuzzies.com/

 

 

Thinking it though though, these folks using 30 inch dobs are up ladders when observing. You can comfortably carry a few orthos in your pockets to save coming back down the ladder again. Try that with Ethos's and your trousers will fall down because of the weight. Not what you want in the dark, in the desert, up a ladder

Not a factor that is generally covered by comparison testing

 

[HollyHound]

On 20/02/2021 at 19:43, Don Pensack said:

I love the 14mm Delos, and almost bought one.  But I loved the 14mm Morpheus more.  Both are quite usable with glasses.

I use a coma corrector on my 12.5", so it's f/5.75 and has a fairly flat focal plane, so I don't see any issues with the 14mm Morpheus,

Some people with much shorter focal lengths who do not use a coma corrector have had issues with FC in the 14mm.

As I read people's remarks, the dividing line appears to be about 1200mm, with longer focal lengths giving it great reviews.

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 😊

[HollyHound]

9 hours ago, Littleguy80 said:

In terms of real world performance, my 9mm Ortho (BGO) shows 4 cores in Stephan’s quintet. The 10mm Delos is a shade behind the Ortho but will still show the same 4 cores. I was never able to see the Quintet with the APM. 100 degree eyepieces are great, my 20mm APM is a keeper, but they are a compromise. I’ve not tried an Ethos but suspect that even they sit behind the Delos. To make your decision it’s really a question of what you value most and what you’re prepared to sacrifice in your observing...and bank balance

Based on a single observing sessions last week, I found that the Ethos 13 matched my Delos 14 (and XW 14) in terms of ability to resolve Trapezium E and F stars.

I would put the Ethos and Delos as pretty much equal in resolving ability, contrast and lack of either astigmatism or field curvature, certainly in my coma corrected f/5 dob.

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” 😀