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21 Ethos or 22 Nagler ?


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Hi folks,

I'm looking at sourcing a second hand low power, rich field eyepiece for my 10" OO Newtonian 1200mm F4.8 shorttube.

Has anyone used either the 21mm Ethos, or 22mm Type 4 Nagler or both ??

I'm interested to know your thoughts, pros and cons.

The 22 Nagler has the better eye relief , but the 21E has the wider field of view.

Or should i simply stick with 1.25" eypeieces and just use my 24 Panoptic ??

Thanks in advance for your thoughts and opinions 🙂

 

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Do you have astigmatism in your observing eye?  If it is greater than 0.5 diopters (check CYL section of your eyeglass prescription), you'll want to either wear eyeglasses or use a Dioptrx.  If this is the case, the 22mm NT4 comes highly recommended.  If not, you could go with the 21mm Ethos or a 20mm APM XWA HDC (or other brandings) if cost is an issue.

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Good advice already given.  You’ve also mentioned the 24mm Panoptic you already have. It’s a super lightweight well corrected eyepiece.  The listed eyerelief is 15mm, same as the Ethos.  If you’re ok with 15mm then that could help your decision.  Many would be fine with a 24 Pan for low power.

However as is often mentioned, TeleVue measure the eyerelief from the glass which is technically correct but doesn’t take into account the fact that the lens elements are not flush with the upper parts of the eyepiece including the rubber eyeguard. That reduces the eyerelief from the technically correct to the more useful available eyerelief.

Ed.

 

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3 hours ago, Rainmaker said:

I owned both the E21 and N22, I now own only the N22 as I didn’t really find the 100 degree field easy to view…

The N22 is just so easy to use….

You might like the 17mm ES-92.  It gives up very little in TFOV to the 22mm NT4 while still being easy to use with eyeglasses.  The whole AFOV is easy to take in.  It's just there in front of your eye like a big picture window.

IIRC, I bought my 22mm NT4 from a seller who replaced his with a 17mm ES-92.  I like them both, so I've kept both.

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It depends on whether 1) you like 100 deg AFOV eyepieces, 2) your observing eye suffers from astigmatism, 3) your budget, 4) you don't mind swapping the 2-to-1.25" adapter in the case that your other eyepieces have 1.25" barrel.

It is also worth saying that with your telescope, the MUCH cheaper 20mm APM HDC would work very well. Without a coma corrector, I am not sure you will be able to distinguish it from an Ethos 21mm, given that any difference between these two eyepieces will be next to the field stop.

 

Personally, I am not a fan of 100 deg AFOV eyepieces, but asked myself the question between the 24 Panoptic and 22mm Nagler T4. Although the 22mm is more immersive, 1) its field stop is only 3mm larger, 2) its weight is 3 times the 24 Pan, 3) I would retain the 24 pan anyway, so this would cost me another £300 assuming that one in the s/h market comes up, and 4) most of my observing is done at medium and high power, not at low power - the 24 Pan is a jolly because it fits in the pocket of my trousers easily - without pulling them down! :D - and can be inserted into the PC2 without having to change the 2-to-1.25" adapter. I only take the latter off when I go really low power using the 30mm APM UFF, but that is not frequent.

Now, people are different of course. If you see yourself buying a set of Ethos eyepieces gradually, then the 21mm can make sense. If I were in the market of 100 deg AFOV eps at that focal ratio, I would add a TV paracorr 2 on top of my list, in order to really take advantage of a clean 100 deg field. 

Edited by Piero
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I've owned both - 21mm Ethos every time for me. My personal experience is that Ethos eyepieces are a touch better in all regards than the Nagler equivalents (apart from weight and cost). Plus I LOVE hyper wide fields of view :smiley:

I currently have the ES 92 17mm as well but still prefer the 21mm Ethos.

Darned expensive preferences to have though - I sometimes wish that I saw things differently :rolleyes2:

 

Edited by John
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I owned both, and currently use the 22mm since I wear glasses at that exit pupil.

Advantages of the 21mm:

--wider apparent field and true field

--distortion in field a little less apparent(mostly because it's farther out)

--slightly better star sharpness than the 22

--slightly better contrast than the 22 (could be simply the magnification).

Advantages of the 22mm:

--longer eye relief

--feels more immersive (hard to describe, but noticeable)

--smaller, lighter

--much less expensive

--fewer elements internally

--doesn't focus in as far as the 21mm

--less rolling of the head to look directly at the edge of the field.

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Thanks to all for your input.

On 28/09/2021 at 00:27, Louis D said:

Do you have astigmatism in your observing eye?  If it is greater than 0.5 diopters (check CYL section of your eyeglass prescription), you'll want to either wear eyeglasses or use a Dioptrx.  If this is the case, the 22mm NT4 comes highly recommended.  If not, you could go with the 21mm Ethos or a 20mm APM XWA HDC (or other brandings) if cost is an issue.

@Louis D I'm not there in the astigmatism department just yet.

My last eye test a year ago revealed 1/4 diopters in my weaker right eye and somewhere between 0 and 1/4 in my left.

I don't use eye glasses to observe.

On 28/09/2021 at 11:16, Rainmaker said:

I owned both the E21 and N22, I now own only the N22 as I didn’t really find the 100 degree field easy to view…

The N22 is just so easy to use….

@Rainmaker Probably my main concern is whether the N22 is as well corrected as the E21. As its a Type 4 i've read its not as good as the Type 6 and certainly not as good with 'fast' scopes below F5.

My Orion Optics is F4.8  You also don't see so many N22s come up second hand. The E21 is in the used ads more often (around the £500 mark) and i wonder if thats because users have tried them and like you say,

not found them so easy to use. 

 

I will do some more looking at the APM XWA 20mm as i've been very impressed with their 15mm/65º series,

and possibly the ES 17/92 or 20/100 although i'm not a fan of their tapered barrels.

Also i could indeed just stick with a Pan 24, but these are really my binoviewing eyepieces, and i'm really looking

for a widefield 2 incher to fill the gap between my current 12.5mm and 35mm options. Also the 35Pan i have won't work with my Newtonian.

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2 hours ago, Space Hopper said:

Also the 35Pan i have won't work with my Newtonian.

What's the issue?  Since it focuses below the reference plane (eyepiece shoulder), in-focus shouldn't be an issue.  It's also well corrected to at least f/4.  Is it just the large exit pupil bothering you?  It should still work well as a finder eyepiece, just with a washed out background sky.

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It gives a 7mm + exit pupil. And out focus (lack of it) is the issue in my scope not in focus ! 😃

I have pretty small 54 yr old pupils.

When i tried the 35 Pan the shadow from the secondary mirror was all too apparent, off putting in fact.

I had exactly the same issue with an old retired scope, a 12" F4 using my 31 Nagler (now sold) as well.

So i thought i'd need an eyepiece in the 20mm range to negate this.

My 35 Pan was a recent second hand buy. I could try it in one of my refractors but i doubt i'd use it much longterm.

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8 hours ago, Space Hopper said:

I will do some more looking at the APM XWA 20mm as i've been very impressed with their 15mm/65º series,

and possibly the ES 17/92 or 20/100 although i'm not a fan of their tapered barrels.

Also i could indeed just stick with a Pan 24, but these are really my binoviewing eyepieces, and i'm really looking

for a widefield 2 incher to fill the gap between my current 12.5mm and 35mm options. Also the 35Pan i have won't work with my Newtonian.

In my 12.5" f/5 scope (f/5.75 with Paracorr), I see it this way in terms of performance:

21mm Ethos > 20mm APM XWA > ES 20mm 100°

So if you're looking for a 100° eyepiece in 20mm +/-, get the Ethos.  And if it's not affordable, get the APM (or Stellarvue Optimus).

You mentioned the 17mm ES 92°.  I recommend, instead, the 17mm Ethos, which I think slightly outperforms the 21mm Ethos.

And unlike the ES 17mm 92°, it's not a boat anchor.

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