82 vs 100 degree AFOV

[Littleguy80]

I’ve just bought a 22mm Nagler Type 4 as a potential replacement for an APM HDC 20mm. My hopes for the Nagler are cleaner/sharper views across the field and improved contrast. The scopes I’m using are a 10” SkyWatcher dob and a Tak FC100DF. 

I managed a brief first list comparison last night though transparency was poor with a fair bit of cloud around. My test targets were M31, M32 and M110. Not too much to be learnt in terms of contrast though M110 did seem slightly more noticeable in the Nagler with the dob. The Nagler seemed noticeably better in the Tak in terms of contrast but I’m cautious to read too much into that due to the drifting cloud. 

The biggest surprise to me was how much narrower the Nagler felt. In terms of TFOV in the dob, the difference is quite small but the presentation of the 82 degree Nagler made it feel much smaller. There are two sides to that coin. On the one side the whole FOV is much more usable but the flip side is that it doesn’t feel quite as immersive as the 100 degree eyepiece. This wasn’t something I thought about beforehand which is probably why it surprised me. This is definitely where it reaches the question of observer preference.

The smaller size and reduced weight of the Nagler is a great benefit and the adjustable design to remove blackouts is great. 

I’m looking forward to more comparisons under better conditions. 

[Alan White]

Neil, that's an interesting finding so far and I await further reporting.
I nearly purchased a Nagler 22 myself, but ended up with the very fine Stella Lyra 20 82, which is super,
the darker sky from a 30 notices.
I also wear glasses due to astigmatism, so eye relief is an issue for me at these lengths.

 

[Don Pensack]

The Nagler 22mm Type 4 is like an old shoe--so comfortable you just don't notice it's there.

I owned one from 1998 to 2010, when it was replaced by a 21mm Ethos.

When I started wearing glasses at the eyepiece due to a worsening astigmatism in 2020, I went back to the 22mm Nagler.  No complaints.

But it is noticeably narrower if directly comparing it to a 100° eyepiece like the APM XWA 20.

The Nagler's Field Stop is 31.1mm wide, while the APM 20 is 34.8mm.

[Louis D]

I bought my 22mm NT4 off a person who found they preferred the view through their 17mm ES-92, despite the TFOV being slightly smaller.  I have both, and I find each has its place.

I really like my new 20mm Founder Optics Marvel 80.  It is hard to pick which is better between it and the NT4.  The Marvel has almost exactly the same TFOV as the ES-92, but a different presentation.  The NT4 has a larger TFOV than either.  The 22mm A-T AF70 (Omegon Redline) even plays well in this group by having a slightly larger TFOV than either the ES-92 or Marvel with similar correction levels and better eye relief than either the Marvel or NT4.  I'm still working up a review of the Marvel.  I just want to spend more time under the stars with it before finalizing it.

[Paz]

I have had a 22mm T4 for years now, its one of my favourite eyepieces, great views, easy to use, and robust. I went this route for good quality wide field with good eye relief,  and I've been very happy with it.

[John]

My 2 inch ultra-wide journey went 22mm T4 Nagler > 20mm T5 Nagler > 21 Ethos I guess over a 5 year period.

I really enjoyed all three. What did surprise me a little was that I preferred the Ethos in terms of sharpness, transmission, light scatter and colour tone to either of the Naglers. That I think is often over-looked with 100 degree eyepieces (I've used a number of types as well as Ethos) they are very fine eyepieces in terms of their overall performance, quite apart from that massive field of view, which is what tends to dominate discussions about them.

 

 

 

Edited August 30 by John

[Littleguy80]

After sessions with the 10" dob and 100mm Frac comparing across multiple targets, I've settled on the Nagler. The Nagler has a small but noticeable edge in contrast though it was close, no doubt the APM's slightly shorter focal length made the difference even smaller. The Nagler's small size also helped though oddly it didn't feel all that much lighter. The difference in FOV size which initially surprised seemed to be less noticeable as I spent more time with it. I did fiddle with the eye positioning adjustment on the Nagler so that may have made a difference with making full use of the FOV it provides. I honestly think I could have stuck with the APM and been happy too. There were targets where the APM's wider FOV framed those targets better. Overall, if you're thinking about getting either of these eyepieces then don't stress too much as both will keep you happy  

Edited September 15 by Littleguy80

[hal9550]

Iv always found that the Jump between AFOVs, when changing eyepiece, tend to colour my opinion on eyepieces - the more extreme the difference, the more i feel it - but i tend to adjust fairly quickly. 

I looked at jupiter a while ago, and jumped between a 9 ortho, Hyperion 13, 7.5 masuyama, and so on - i was looking for a sharp image, and i certainly got it - but the AFOV changing between 40 odd and just under 70 was stark - 

I intend never to look through a 100 degree EP, lest i get ideas, and attempt to upgrade my whole kit!!

[Louis D]

Agreed.  The Morpheus' AFOV looks nice and wide until I switch back to one of them from one of my ES-92s.  Then I suddenly get a bad case of claustrophobia. 😄

[hal9550]

On 18/09/2024 at 15:55, Louis D said:

Agreed.  The Morpheus' AFOV looks nice and wide until I switch back to one of them from one of my ES-92s.  Then I suddenly get a bad case of claustrophobia. 😄

I have felt that when you jump by more than 10 degrees of AFOV, you tend to really appreciate the difference. I have some basic 66 degree SVBonies, which i use  - but when i throw on my Meade UWA 5.5 at 82 degrees, it dwarfs them - 

Same when going from one of the Orthos - very narrow, but change to something mid 60s and BOOM - it feels vastly different

To be honest, i think i should make it a mission, Never to look through anything above 82 degrees!!! I dont want to be back here in a year talking about buying 5-6 XWA eyepieces! 

[John]

1 hour ago, hal9550 said:

....To be honest, i think i should make it a mission, Never to look through anything above 82 degrees!!! I dont want to be back here in a year talking about buying 5-6 XWA eyepieces! 

I tend to agree - I found it a slippery slope. Oddly it was comparing a Pentax XW 10mm with it's Nagler equivalent (a Type 6 9mm) which put me onto the hunt for something with the neutral tone of the XW, the sharpness, the light scatter control but with a very wide angle of view. I found that mix with the Ethos range, which did prove expensive of course 🙄

 

[hal9550]

44 minutes ago, John said:

I tend to agree - I found it a slippery slope. Oddly it was comparing a Pentax XW 10mm with it's Nagler equivalent (a Type 6 9mm) which put me onto the hunt for something with the neutral tone of the XW, the sharpness, the light scatter control but with a very wide angle of view. I found that mix with the Ethos range, which did prove expensive of course 🙄

 

Its akin to aperture fever - Something we all suffer from time to time. I can usually overcome aperture fever with some logical arguments

• Im at 8" and i always have difficulty setting up the equipment - imagine what a difference to payload (both for my mounts, and my back) the next size up will be
• 8" is respectable - be happy 
• Yes bigger is better, but i have limited space in my apartment - 
• the argument 'Bigger is better' will continue to apply at all times - do i plan on having a 24" in an observatory? What then? 
• If i buy a bigger scope my wife will leave me!

I think 'AFOV fever' is similar, but you can kinda get sucked in easier. Its eyepieces after all, and we probably all have too many! 

My first 82 degree was the Meade UWA 5.5 - that was my first 82 degree, or UWA sibling - and yea it kinda hooked me in, slowly at first. But here we are! Im currently embarked on my merry journey to Ultra wide angle heaven.

I will just refuse to look through AFOVS with greater than that, and avoid more expenditure! and il BE HAPPY! 

Well done on your ethos project! Im jealous of course. My intention is to avoid looking through them, or the famed Delite, and its 'white pearls on black satin' view of the stars. If i go down that road, il end up properly addicted!

 

[John]

39 minutes ago, hal9550 said:

Its akin to aperture fever - Something we all suffer from time to time. I can usually overcome aperture fever with some logical arguments

• Im at 8" and i always have difficulty setting up the equipment - imagine what a difference to payload (both for my mounts, and my back) the next size up will be
• 8" is respectable - be happy 
• Yes bigger is better, but i have limited space in my apartment - 
• the argument 'Bigger is better' will continue to apply at all times - do i plan on having a 24" in an observatory? What then? 
• If i buy a bigger scope my wife will leave me!

I think 'AFOV fever' is similar, but you can kinda get sucked in easier. Its eyepieces after all, and we probably all have too many! 

My first 82 degree was the Meade UWA 5.5 - that was my first 82 degree, or UWA sibling - and yea it kinda hooked me in, slowly at first. But here we are! Im currently embarked on my merry journey to Ultra wide angle heaven.

I will just refuse to look through AFOVS with greater than that, and avoid more expenditure! and il BE HAPPY! 

Well done on your ethos project! Im jealous of course. My intention is to avoid looking through them, or the famed Delite, and its 'white pearls on black satin' view of the stars. If i go down that road, il end up properly addicted!

 

One of my drivers towards the very wide field of view was that I have tended to own faster scopes, ie: F/6, F/5.3, F/4.8 etc. My skies are generally impacted by light pollution to some extent so being able to have a wide true field combined with higher magnifications (and darker background sky) and to maintain an effective exit pupil were plusses for the hyper wide eyepieces. The fact that the Ethos range were also superb optical performers added to their allure.

Expensive and fun for a decade or so but I've reverted to more modest 50-72 degree AFoV eyepieces now which seem to suit the refractors, that I use most often, better in terms of ergonomics. A mix of Tele Vue's and Pentax currently so still good to look through.

 

Edited Monday at 13:03 by John

[hal9550]

19 hours ago, John said:

One of my drivers towards the very wide field of view was that I have tended to own faster scopes, ie: F/6, F/5.3, F/4.8 etc. My skies are generally impacted by light pollution to some extent so being able to have a wide true field combined with higher magnifications (and darker background sky) and to maintain an effective exit pupil were plusses for the hyper wide eyepieces. The fact that the Ethos range were also superb optical performers added to their allure.

Expensive and fun for a decade or so but I've reverted to more modest 50-72 degree AFoV eyepieces now which seem to suit the refractors, that I use most often, better in terms of ergonomics. A mix of Tele Vue's and Pentax currently so still good to look through.

 

Yes light pollution tends to ruin the game altogether - my intention is to try and obtain some reasonably priced Light Pollution Filters 

Just on the off chance anyone is in the market for new equipment, i should say Astroshop currently has an 'Autumn Sale' on

[John]

26 minutes ago, hal9550 said:

Yes light pollution tends to ruin the game altogether - my intention is to try and obtain some reasonably priced Light Pollution Filters 

Just on the off chance anyone is in the market for new equipment, i should say Astroshop currently has an 'Autumn Sale' on

Of the various deep sky filters that I've tried, I've found the UHC and O-III types the most effective followed by the H-Beta, the latter enabled me to see (well, glimpse) the Horse Head Nebula with my 12 inch dob a couple of times. The UHC and O-III filters are much more versatile although with all of these it is nebulae that are the beneficiaries. I've not found a filter that improves the views of galaxies, other than being under a dark sky !

On filters, my personal view is that quality really does make a difference to the impact they have. Astronomik are a good name to look out for in terms of brands.

Edited Tuesday at 08:54 by John

[hal9550]

Probably widely known but the stated AFOV of many eyepieces seems to vary, quite substantially, from the actual performance - 

Got my SWA Meade Japanese, and its definitely a shade smaller, in terms of actual AFOV - rated at 67, but Don was saying 63 - and i would definitely confirm that. 

Not that its BAD  - its lovely! But i jumped to a 68 degree SVB, and you can tell, with ease - there is a noticeable difference

It does make me wonder why they dont offer proper specs! Dons guide over on cloudy nights is a life saver for actual real AFOVs

[John]

2 hours ago, hal9550 said:

Probably widely known but the stated AFOV of many eyepieces seems to vary, quite substantially, from the actual performance - 

Got my SWA Meade Japanese, and its definitely a shade smaller, in terms of actual AFOV - rated at 67, but Don was saying 63 - and i would definitely confirm that. 

Not that its BAD  - its lovely! But i jumped to a 68 degree SVB, and you can tell, with ease - there is a noticeable difference

It does make me wonder why they dont offer proper specs! Dons guide over on cloudy nights is a life saver for actual real AFOVs

True, unfortunately. I have to say though that, generally, Tele Vue's stated specifications are accurate.

Guides such as Don's plus evaluations by folks such as the Russian tester known as "Ernest" are invaluable resources.

[hal9550]

1 hour ago, John said:

True, unfortunately. I have to say though that, generally, Tele Vue's stated specifications are accurate.

Guides such as Don's plus evaluations by folks such as the Russian tester known as "Ernest" are invaluable resources.

Dons guide is solid - 100% useful in fairness

Ernests Tests are epic too - i have to say, my temptation is to buy up most of the reasonably priced 'EXCELLENT IMAGE' eyepieces, as they become available second hand - it does allow us to get an idea of where the value lies - there's certainly a few oddities in my opinion - two of the Celestron X-Cel LX eps for example - the Meade HD-60 6.5mm - if i ever get reasonable second hand prices on these, im getting them - i know i have too many eyepieces, but you cant beat quality. Happily some of the highly commended lot, are already in my kit

Equally important is the Blue Highlighted 'VERY BAD IMAGE' warnings - definitely a case of Buyer beware

It saved me from wasting money on the 24mm ES82 - i had that pencilled in when i began this thread, but i very quickly removed it in favor of the 22mm Redline from Omegon - not in ernests tests, but i havent heard anything but stellar reviews for the price!

Having access to test results on eyepieces is invaluable, and when you combine that with Dons Buying guide - well, you cannot put a foot wrong, unless you are simply not paying attention!!

[Don Pensack]

8 hours ago, hal9550 said:

Yes light pollution tends to ruin the game altogether - my intention is to try and obtain some reasonably priced Light Pollution Filters 

Just on the off chance anyone is in the market for new equipment, i should say Astroshop currently has an 'Autumn Sale' on

40 years ago, a broadband filter was a reasonable choice for reducing light pollution for deep sky objects in the telescope.

They still are today IF the filter is used at a site with already quite-dark skies. (say, 21.0 and darker).

Broadbands work fairly well to reduce the oxygen glow in the atmosphere at night that is a strong component of sky light at a dark site.

 

The problem is that we now have over 40 different kinds of outdoor lighting in cities, pretty much covering the entire spectrum, so reducing light pollution at the eyepiece also just means

cutting out most of the light of the object.  In other words, broadband/LPR/CLS filters just no longer work more than just a tiny bit, so they're really not worth acquiring.

 

With stellar objects like stars and clusters of stars, you can improve contrast merely by increasing magnification.  Stars don't dim with magnification, while the background sky does.

A star cluster barely seen at 30x will look pretty nice at 120x.

With extended objects like emission or planetary nebulae, a narrowband UHC or O-III filter can help.

With galaxies, dark nebulae, reflection nebulae, or telescopic comets, or extremely faint nebulae, the only thing that helps is to drive the telescope away from the lights to darker skies.

 

If you get just one filter, it should be a narrowband (transmitting H-ß and O-III lines), or "UHC-type".

That way, you needn't do research into the strength of each spectral line--you'll just know there will be enhancement.

Some recommended examples:

Astronomik UHC 2017 and later

Tele Vue BandMate II Nebustar 2018 and later

DGM NPB 2018 and later

Lumicon UHC 2005-2012 and 2018-2022, and 2024 to now.

ICS UHC

Thousand Oaks LP-2

Orion Ultrablock (now out of production, but some retailers might still have stock).