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ES 17mm 92 or APM 20mm 100 - Help a guy decide

cassegrain eyepieces SCT Celestron
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#1 Ryan555_1

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Posted 18 June 2018 - 02:31 PM

Hello forum,

 

I have a CPC 1100 Edge and I am presently making a decision on an eyepiece that would fill the mid-range of magnifications for my scope. Right now, I mostly use a Luminos 23mm to fit the bill. That and my 12mm Delos see the most time. Right now, I am a bit split between two eyepieces: ES 17mm 92 and APM 20mm 100, preferring the latter at the moment, mostly because of it's ideal focal length for the scope. (Note: I am not considering Ethos yet, since I have never owned a 100 degree eyepiece and want to make sure I really like them.)

 

My question to you all: which would you get in my situation? 

 

There are obviously pros and cons of both. I like the magnification, exit pupil, and weight of the APM. I like the Delos-on-steroids feel of the ES 17mm. I like that you can easily take most of the FOV in, unlike the APM. However, I find myself preferring 20-23mm over 17mm in my scope. It seems like the APM 20mm will have the best view for most DSO objects I am looking at. Tell me if I'm wrong. I know some that really like the 17mm in this scope. Another consideration is that I suspect that, if I buy the ES 17mm, I will also need to buy eventually a 22-23mm for that range (The Luminos is not my favorite by any means). The 20mm APM would be a nice in between 17mm and 23mm, making those less necessary and thus perhaps saving an extra eyepiece to lug around. (On the other hand, the jump from 20mm to 12-13mm is a big one.) These are just my thoughts right now....

 

Anyway, I can go either way. So I thought I would ask advice to the forum. Any advice is welcome, and especially if you have this scope or a related one. 

 

EDIT: It might be helpful to add that I use my telescope in a very light polluted area of Phoenix (zone 9) about 70 percent of the time and a dark site (zone 2) the rest of the time, about once a month, as the weather and wife permits. 


Edited by Ryan555_1, 18 June 2018 - 02:47 PM.

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#2 havasman

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Posted 18 June 2018 - 03:07 PM

I can tell you the APM HDC 20mm is a very fine eyepiece. Mine replaced an ES100 20mm and the best thing I can tell you is that I use the 20mm focal length much more now than ever before. It's a keeper and I have no need for the 21 Ethos, though I have looked through and admired others'. I have several Ethos/Delos and I'm not really convinced that they are appreciably better than the APM HDC's. It's extremely likely I will replace 6 and 8mm Delos with the 7mm HDC when it comes out early next year. I may pick up a 13mm to test against my 13 Ethos. I consistently recommend the APM HDC's.

 

Three comments on the 100o AFOV: many observers take in the entire field effortlessly, many feel the freedom from seeing the field stop is the essence of the design and like how it enhances the connection with the viewed object by its absence, and everybody that makes the yes/no choice based on their experience and preferences is correct.

 

I am not sensitive to eye relief so the primary design advantage of the ES92's is lost on me and their size & weight are not worth my trouble because of that. Folks that have them do love 'em.


Edited by havasman, 18 June 2018 - 03:14 PM.

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#3 NiteGuy

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Posted 18 June 2018 - 03:12 PM

The Lunt 20mm HDC has recieved very high compliments and praise for both quality and its low cost. This may be the same as the APM HDC 20mm?


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#4 areyoukiddingme

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Posted 18 June 2018 - 03:22 PM

So far as I know they are the same. I have the Lunt badged 20mm/100 and it competes very strongly with the 21 Ethos.

 

I no longer have a 20 ES/100 to make direct comparison with, but the astigmatism at the edges and difficulty of getting the full 100 degrees are strong in my memory, and not features of the Lunt/APM.

 

Given the lower price of the APM, as well as much lighter weight, it's not really much of a competition for the ES, only the Ethos.

 

I also had the 17mm ES/92, which I compared with 17 Ethos and 17 Nikon HW (102 degree). I rank them in terms of optical sharpness Nikon, Ethos, ES, but the differences are quite close.

 

The extraordinary weight of the ES would have ruled it out for me even if it were as sharp as the others. But if you have a very stable mount, and you like the eye relief/immersive field, I can see why people would choose it.

 

Compared to the APM 20 the ES is going to be optically very similar in quality, but the ergonomics are very different. It's the ergonomics that would decided it for me.


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#5 vkhastro1

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Posted 18 June 2018 - 03:24 PM

The Lunt 20mm HDC has recieved very high compliments and praise for both quality and its low cost. This may be the same as the APM HDC 20mm?

The APM and Lunt are the same eyepiece.


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#6 wky46

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Posted 18 June 2018 - 03:41 PM

Thanks to havasmans suggestion in another thread, I purchased the APM 20mm

 

I bought it primarily for my 16” Dob but circumstances haven’t allowed me to do that yet but in my 10” SCT it’s easily my favorite EP I’ve owned to date (though I wish I never sold my 24mm Pan smirk.gif )

 

Never tried an ES nor an Ethos but I don’t really feel the need to, now


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#7 vkhastro1

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Posted 18 June 2018 - 03:41 PM

I own the Lunt 20mm 100° version and the ES 17mm 92° eyepiece.

Both eyepieces are awesome in their own right.

I also own the Ethos 21mm eyepiece - prefer the Lunt 20mm 100° and ES 17mm 92° over the Ethos.

Totally different presentation:

Lunt 20mm - lighter weight, less eye relief, excellent contrast and lack of optical aberrations, no EFOB, need to move my eye around to take in full AFOV.

ES 17mm - very heavy (may cause balance issues), long eye relief, excellent contrast and lack of optical aberrations, no EFOB, easily take in full AFOV without moving my eye around.

 

Looking at the eyepieces and scopes you own, my suggestion is to sell the Luminos 15mm and 23mm and 17mm Stratus and buy the APM 20mm 100mm ! Nicely covers the 2mm exit pupil eyepiece with your CPC 1100 HD


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#8 rowdy388

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Posted 18 June 2018 - 04:33 PM

I also own the ES92 17mm and APM HDC 20mm. The 20 gets little use because I prefer

the view through the 17. I don't need the extra eye relief of the 17. It's the presentation of

the 17 that makes it shine. Not saying the APM 20 isn't a fabulous eyepiece but it isn't quite

as well corrected or have that immersion pop of the 17 IMO.


Edited by rowdy388, 18 June 2018 - 04:39 PM.

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#9 Ryan555_1

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Posted 18 June 2018 - 06:25 PM

I can tell you the APM HDC 20mm is a very fine eyepiece. Mine replaced an ES100 20mm and the best thing I can tell you is that I use the 20mm focal length much more now than ever before. It's a keeper and I have no need for the 21 Ethos, though I have looked through and admired others'. I have several Ethos/Delos and I'm not really convinced that they are appreciably better than the APM HDC's. It's extremely likely I will replace 6 and 8mm Delos with the 7mm HDC when it comes out early next year. I may pick up a 13mm to test against my 13 Ethos. I consistently recommend the APM HDC's.

 

Three comments on the 100o AFOV: many observers take in the entire field effortlessly, many feel the freedom from seeing the field stop is the essence of the design and like how it enhances the connection with the viewed object by its absence, and everybody that makes the yes/no choice based on their experience and preferences is correct.

 

I am not sensitive to eye relief so the primary design advantage of the ES92's is lost on me and their size & weight are not worth my trouble because of that. Folks that have them do love 'em.

I did not realize a new HDC is coming out. 7mm would be nice. Are any other focal lengths coming out soon?



#10 Ryan555_1

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Posted 18 June 2018 - 06:28 PM

Looking at the eyepieces and scopes you own, my suggestion is to sell the Luminos 15mm and 23mm and 17mm Stratus and buy the APM 20mm 100mm ! Nicely covers the 2mm exit pupil eyepiece with your CPC 1100 HD

This was my inclination exactly. Thanks for the help. I am still not settled, but the exit pupil of the 20mm really hits the sweet spot. 



#11 havasman

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Posted 18 June 2018 - 06:36 PM

I did not realize a new HDC is coming out. 7mm would be nice. Are any other focal lengths coming out soon?

Not that I know of. I emailed Marcus last week about expansion of the line in medium-short focal lengths and he told me the 7 is in the works @ 6 months out. That fills a hole that, for many scopes, needed filling.


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#12 vkhastro1

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Posted 18 June 2018 - 07:04 PM

Not that I know of. I emailed Marcus last week about expansion of the line in medium-short focal lengths and he told me the 7 is in the works @ 6 months out. That fills a hole that, for many scopes, needed filling.

 

Awesome - great focal length between the 9mm and 5mm (actually 4.77mm ) !

Definitely on my future buy list.


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#13 Procyon

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Posted 18 June 2018 - 09:09 PM

Get the ES 17 92 now since there's a sale and get the 20mm APM 100 sometime later on. I have a 20mm APM 100 coming and will let you know soon if the views (not the quality) are different or too similar.

#14 Ryan555_1

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Posted 19 June 2018 - 11:33 AM

Get the ES 17 92 now since there's a sale and get the 20mm APM 100 sometime later on. I have a 20mm APM 100 coming and will let you know soon if the views (not the quality) are different or too similar.

That's an idea. I still haven't decided, but I am leaning towards the APM first, given its ideal FOV for me. When is your APM coming in? It must be crossing the pond!



#15 Procyon

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Posted 19 June 2018 - 11:36 AM

It should be coming soon I'm guessing.

#16 faackanders2

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Posted 04 July 2018 - 07:15 PM

I would go for widest 20mm 100 AFOV first. ES always has lowest price.

For 17mm I would go with NIKON NAV 17 HW with EiC-14 102 deg AFOV since it is a two for one 17mm and 14mm.

Edited by faackanders2, 04 July 2018 - 09:52 PM.

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#17 havasman

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Posted 04 July 2018 - 07:38 PM

I would go for widest 20mm 10 AFOV first. ES always has lowest price.

For 17mm I would go with NIKON NAV 17 HW with EiC-14 102 deg AFOV since it is a two for one 17mm and 14mm.

Current pricing, July 4, 2018

ES100 20mm retail = $449.99

APM HDC 20mm retail = $329.00

same USA dealer, no discounts

 

I and others have found the head-to-head performance of the APM superior to the ES. The APM HDC 20mm is a very good eyepiece. For the several years I had the ES100 20mm I thought it was a good eyepiece.

 

Extended eye relief is not any advantage for me so the cost and size of the ES92 series is not a good choice for my kit. But folks that have 'em love 'em.


Edited by havasman, 04 July 2018 - 07:49 PM.

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#18 Ryan555_1

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Posted 05 July 2018 - 01:38 AM

I got the APM 20mm for $280 (https://farpointastr...angle-eyepiece/). Trying it out at the darkest skies I've ever been to. All I can say is wow!
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