Wider FOV 68 Vs 82 Degree for a fast scope

[Ratlet]

I'm contemplating getting a new eyepiece.  I've mostly been rocking BST's (8mm and 12mm) and an SVBONY 3-8mm zoom so nicely in the 60 degree FOV, I do also have a 32mm plossl which I use with the 130PDS as a finder.  I wanted to see what a larger FOV would be like and have been considering what would be the best bet to get a good feel for it.

From what I understand, an FOV larger than 70 ish degrees means you'll have to look around the eyepiece.  I've tried looking around in my current eyepieces and experience blackouts which is because I've been doing it wrong (as your eyeball moves side to side the pupil basically moves in and out by a couple of mm) and I need to move my head slightly to compensate.  I found it a bit frustrating which is pushing me more towards the 70 degree rather than the 80 degree, however I've been wrong in astronomy more than right to the point that I've started writing PBEG on my reports (Problem Between Eyepiece and Ground) to try and hide it so it might be once I adjust to using an 80 degree eyepiece I'll prefer it.

I think I'm well served with narrow focus eyepieces and think that something between 13-20mm with a larger FOV would be better.  At the moment I've been mostly looking at the Baader Hyperion or OVL Nirvana.  Does anyone have a suggestion or recommendation on a wider FOV eyepiece around £150 that would give me a good representative experience in an F5 scope.  In terms of image quality they'll be up against the Starguiders.

So far the forum is 100% success on visual astronomy suggestions for me.

[Stu1smartcookie]

Hi, i can only speak of my experience in using 82 degree EPs .. i had three celestrons ... 10mm, 15mm and the giant 31mm ( very heavy ) .. they were all good in so much as they gave nice flat views but i simply couldnt get on with the wide FOV they showed . I found myself being distracted , especially in the case of the 31mm . the widest fov EPs that work for me , so far , are the hyperions from baader which i believe offer 68 degrees . In fact i actually prefer lower more narrow fov EPs . Its just my opinion and i'm sure someone else will comment that the 82 degree EPs are a wonderful addition . 

Stu

[Ricochet]

Are you using your Starguiders without glasses and the eyecups twisted all the way up? With that method I've never had any issue with blackouts but when I tried to look through one where someone hadn't raised the eyecup it was a lot more difficult.

As for the choice between the Hyperion and Nirvana it all boils down to whether you need to wear glasses for observing or not. If you don't wear glasses, go for the Nirvana. If you do wear glasses search the forum to try to find out which focal lengths are good and which are bad with fast focal ratio scopes. Unfortunately, I can't remember which ones are which. If you want 68° that works well at F5 and don't need glasses then I would be looking at the ES68 and UFF lines. I believe that the 12 and 14.5mm eyepieces in the Stellalyra 68° line are decent performers too.

[wulfrun]

I have one Nirvana, the 16mm and it gets frequent use in all three of my scopes (f/4.4, f/5 and f/8). I like the wide field, particularly for longer "dwell time" in the two untracked scopes, i.e. less nudging. Personal taste and depends on what you're looking at too. I also have another 82-degree in 9mm (Nagler), that also sees a lot of use. Again, personal opinion but using narrow FOV eyepieces seems like looking down a straw once you've used wide ones regularly.

[azrabella]

I suppose a lot depends on what you observe. BST's have been my fall-back eyepieces for years, and at 60 degrees they are a good choice in most any scope. I also have two Nirvana eyepieces (13mm and 16mm) and they do take some getting used to, but when your brain/eye has made the adjustment then they are most useful additions. BTW, both less than £100 each new. My favourite eyepiece is an old SWA 70 degree 17mm. It fits midway between the BST's and Nirvana and is a good general purpose ocular - at least, for me.

[bosun21]

My personal experience was similar to your origins in the eyepiece world. I started with all the Starguiders apart from 3.2mm , and then bought individual eyepieces of varying FOV and quality just to cast my own opinion on the cost against quality question. I found that my perfect for me zone fell in between 70 - 80 degrees. I also discovered a vital lesson of buy quality, buy once! So I have settled on all the Baader Morpheus eyepieces complemented by an ES 24mm 68 degree and a 2x ES tele-extender. I also have a set of Nirvanas from 4 - 16mm which are excellent for the price. Once you find your keeper you will know. Good luck.

[Kon]

I also started with the BSTs but upgraded to ES. I have the ES 82 degrees (6.8, 8.8 and 14mm) and I would not go back to smaller FOV, especially with my 8" Dob F6; I am contemplating 100degrees now as I am enjoying the immersion during my visuals. You get an excellent framing of large clusters and some of the large nebulas. Like @bosun21, I have the ES24mm 68 as I do not want to switch from 1.25" to 2" (personal preference), so that's my lowest power one which has an almost similar FOV to my 30mm Plossl (looking to upgrade for wider views). I find them corrected to the edge without any issues. I do not feel that I need to move my head to get the whole view. Be aware they have a very tight eye relief so if you wear glasses to observe, you will find them tricky.

[Zermelo]

I have found the 16mm Nirvana to be very pleasant, in all my scopes. I still can't believe it's under £100 new.

I have one ES 82 degree, the 6.7mm. It's very sharp and controls light well, though I find it gives slightly dimmer images than some of my others.

You should probably steer clear of Hyperions at F/5, but I've found the Morpheuses to be excellent. They are "only" around 76 degrees, but the experience is more immersive than I get from either the Nirvanas or ES.  I've picked up four of them now. Unfortunately they're £230 new, but you might get one second hand for your target price, if you're lucky and/or quick-fingered. Three of my four were.

Only you can decide whether or not it's worth the spend to go from 60 to 70+
If you can get a look through someone else's at a club night before buying, it might help,

[PeterC65]

I've settled on Explore Scientific eyepieces (the 68° and 82° ranges - I'm less sure about the 62° range, and the 52° range is definitely not as good). They offer good performance at a mid-market price point, there is a wide range from which to choose, they are really well made and feel bomb proof (sealed). I've considered the Nirvana's as they are cheaper, but the range is smaller. I also have the Baader Zoom and Baader Aspheric 36mm which I like, but not as much as the ES eyepieces.

Getting back to the question about field of view, the ES 68° 24mm is my favourite and most used eyepiece. I love that it fills my field of view giving a very immersive experience, so much so that I'm always a little disappointed now with eyepieces having a smaller field of view, such as the Baader Zoom at 24mm which gives about 48°.

Having experienced 68°, I was also wondering what the 82° experience would be like, so my other ES eyepieces are all 82° (14mm, 8.8mm, 6.7mm. 4.7mm - I also have a 52° 3mm). Below 16mm the eyepieces are all 82° rather than 68°. For me the 82° just means there is some more sky beyond my immediate field of view that I can look around to check what is just beyond what I'm seeing. If there is something interesting out there then I slew the scope to centre it. I don't observe those edge objects as the 'looking around' isn't easy on the eye. So in practice I use the 82° eyepieces as I do the 68°, just with the ability to look outside the immediate field of view.

I understand that manual Dob users like a wider field of view because they don't have to nudge the scope so often, but I wouldn't want to be observing something that was much off centre.

If I were buying again I would get the ES 68° 16mm instead of the ES 82° 14mm, and I would avoid buying any eyepiece that was less than 68°.

 

[Mr Spock]

I use Nirvanas in all my scopes. I can't think of anything that's better value for money. They are sharp and easy to look through - none of the blackouts and other weird effects you get with Naglers.

[bosun21]

25 minutes ago, PeterC65 said:

. I've considered the Nirvana's as they are cheaper, but the range is smaller.

Are you aware that there’s another two additions to the Nirvana range? The 10mm and the 13mm.

[PeterC65]

1 hour ago, bosun21 said:

Are you aware that there’s another two additions to the Nirvana range? The 10mm and the 13mm.

No I wasn't, thanks for pointing that out. So the Nirvana range is now similar to the ES 82° range but half the price. I would seriously consider the Nirvanas if I were buying again. I'd still buy an ES 68° 24mm though!

[Mr Spock]

1 hour ago, PeterC65 said:

I'd still buy an ES 68° 24mm though!

I think now the StellaLyra UFF 24mm is a serious contender in that focal length.

[PeterC65]

1 hour ago, Mr Spock said:

I think now the StellaLyra UFF 24mm is a serious contender in that focal length.

Perhaps, but 29mm of eye relief would be too much for me.

[Second Time Around]

The usable eye relief is very much less than the quoted figure. In fact it's only just enough for some people who wear glasses to see the full FOV. However, it has more eye relief than the ES 24/68, and even more than the Panoptic 24/68.

[Louis D]

38 minutes ago, PeterC65 said:

Perhaps, but 29mm of eye relief would be too much for me.

Due to eye lens recession, it has about 17mm of measured, usable eye relief.  This is about perfect for eyeglass wearers with the eye cup flipped down.

[Louis D]

I've found that the longer the eye relief, the easier it is to see the entire field all at once in a relaxed manner, with or without eyeglasses.  My 17mm ES-92 with 16mm of eye usable relief has a much easier to take in AFOV than my 20mm Meade 5000 UWA with its 12mm of eye usable relief even if I take off my eyeglasses.  Part of that may be my deep set eyes.

To examine the edges, the required head tipping seems more extreme in the Meade despite having a narrower AFOV.  The problem is, adding long eye relief to SWA, UWA, and HWA eyepieces generally makes them bigger, heavier, and more expensive than their limited eye relief equivalents.

[Elp]

With the meade 82 I've found you also have to physically move around slightly to see the whole field to the edge, it's not just a case of moving your eyes. Are they worth the extra for the fov? Not sure, I'd prefer long eye relief.

[Don Pensack]

Human vision has a sharp center of 2-5° wide.

With an apparent field up to 68° or so, you can simply move the eye to look at the field, providing the image forms far enough away from the eye.

With anything wider, moving the eye sufficiently to look at the edge will move the pupil of your eye off the exit pupil of the eyepiece.

You have to roll your head over a bit to use direct vision to look at the edge.

And, the wider the apparent field, the more you have to roll the head to look at the edge.

If you stop to think of it, the edge of the field in a 100-120° eyepiece is closer to parallel to the scope than it is to perpendicular.

Some people don't mind moving the head (I'm one), while others simply hate it (maybe they have arthritis in their necks?).

 

Now, your peripheral vision extends to about 145° horizontal and 125° vertical, so seeing the edge of the field with peripheral vision when staring at the center of the field is easy.

It's looking at the edge with direct vision where you have to roll your head.

[Ratlet]

Thanks for the feedback folks!  Didn't expect it to garner quite as much attention as it did.  I did try to do a massive post to respond to everyone but it got massive quickly.  I think everyone various points that are important for my to consider, part of the reason I ask here, you get useful feedback and opinions with people sharing their experiences where as elsewhere it can get a bit... frisky.

I think on the balance of what everyone has said I will get the 16mm Nirvana.  I'm wanting to find out how I get on with a wide field of view to see if I like it and it sounds like it will provide a very acceptable view.  I like the FOV of the eyepiece in total as well as the FOV of the central 68 degrees (It fits nicely with the rest of my collection).  It looks a lot to me like if it's something I'll enjoy or learn to enjoy then I'll know.  Tempted to order a SVBONY Redline 20mm.  Not expecting miracles out of it, but I think it would be nice to compare a similar slice of the sky with different eyepiece FOV and exit pupils.

I'm really enjoying this experimental side of things (it's also gives me a good excuse for my expanding eyepiece collection) and it's a really nice feeling when you experience something and can relate it to what you've read or been told.

Thanks again everyone!  Let's see if the forum can continue it's run of helping me populate my eyepiece case with affordable winners.

[bosun21]

4 minutes ago, Ratlet said:

Tempted to order a SVBONY Redline 20mm. 

I wouldn’t if I was you unless you’re a lover of kidney beans.

[Second Time Around]

2 hours ago, Don Pensack said:

Human vision has a sharp center of 2-5° wide.

With an apparent field up to 68° or so, you can simply move the eye to look at the field, providing the image forms far enough away from the eye.

With anything wider, moving the eye sufficiently to look at the edge will move the pupil of your eye off the exit pupil of the eyepiece.

You have to roll your head over a bit to use direct vision to look at the edge.

And, the wider the apparent field, the more you have to roll the head to look at the edge.

If you stop to think of it, the edge of the field in a 100-120° eyepiece is closer to parallel to the scope than it is to perpendicular.

Some people don't mind moving the head (I'm one), while others simply hate it (maybe they have arthritis in their necks?).

 

Now, your peripheral vision extends to about 145° horizontal and 125° vertical, so seeing the edge of the field with peripheral vision when staring at the center of the field is easy.

It's looking at the edge with direct vision where you have to roll your head.

I have a damaged neck and, having tried wider field eyepieces, find I much prefer 60 to 70 degree AFOVs.

My favourite eyepiece of all is the 7.7-15.4 mm APM Superzoom.  Unlike most medium power zooms this has an almost constant AFOV.  This is 66-67 degrees, that I find ideal.  If I want shorter focal lengths I Barlow the zoom and so keep the same AFOV.

[Louis D]

3 hours ago, bosun21 said:

I wouldn’t if I was you unless you’re a lover of kidney beans.

No SAEP in the SVBONY Redline 20mm, if that's what you're alluding  to.  Notice there's no significant shadowing in it's AFOV image in the third row, far right.

3 hours ago, Ratlet said:

Tempted to order a SVBONY Redline 20mm.  Not expecting miracles out of it, but I think it would be nice to compare a similar slice of the sky with different eyepiece FOV and exit pupils.

It is a poor performer in the outer field below f/8 for certain.  However, at f/18 in my binoviewer, they are terrific as a binoviewing pair for eyeglass wearers.

Here's my write-up on it:

 

[Ratlet]

17 minutes ago, Louis D said:

No SAEP in the SVBONY Redline 20mm, if that's what you're alluding  to.  Notice there's no significant shadowing in it's AFOV image in the third row, far right.

It is a poor performer in the outer field below f/8 for certain.  However, at f/18 in my binoviewer, they are terrific as a binoviewing pair for eyeglass wearers.

Here's my write-up on it:

 

I think I've been calling kidney beaning what is actually black outs due to have the eye the wrong distance from the eyepiece.  I noticed it with my 32mm plossl when I try to view without my glasses or my Starguiders if I don't adjust the eyecup.  It's also why I don't even consider using my 32mm barlowed, it's too hard to keep my eye in right place.

The redlines have a reputation for kidney beaning but is it the case that it's the eye not being at the right place due to eyerelief?

I'll be honest that I'm fully expecting it to not be great at F5.  As far as I can tell all the eyepieces I have perform well out to the edge.  It will be interesting to actually see how it affects the image.

But please, no more talk of binoviewer.  I'm hanging on to my resistance to getting one by the skin of my teeth at this point.  The fact that this eyepiece is highly rated and affordable for binoviewing is a complete coincidence...

[Louis D]

14 minutes ago, Ratlet said:

The redlines have a reputation for kidney beaning but is it the case that it's the eye not being at the right place due to eyerelief?

The 6mm and 9mm versions certainly do suffer from SAEP.  Both also perform fairly well in faster scopes.  The reason for both results is the 6 and 9 employ a Smyth lens group to amplify the focal length.  This slows down the light cone, improving edge performance.  However, the matching of the Smyth and image forming groups was poorly done, leading to SAEP.

The 15mm and 20mm versions have no Smyth group.  They are purely positive designs which rarely suffer from SAEP.

18 minutes ago, Ratlet said:

It's also why I don't even consider using my 32mm barlowed, it's too hard to keep my eye in right place.

Barlows tend to push out the eye relief and induce SAEP in my experience.  Both make holding the exit pupil more difficult.  This may be what you're experiencing with the Barlowed 32mm.  If you used a telemagnifier like a TV PowerMate instead, you would not experience either issue.