16mm Nirvana 82 to replace a 16mm ES Maxvision?

[kev100]

Hi,

As much as I love my 16mm Maxvision, I'm starting to find the 68 degree fov and eye relief a little restrictive, and wondered about replacing it with a 16mm Nirvana. I've read good things about these, and they seem to fare well in fast scopes. Just wondered if anyone had any direct comparisons with the Maxvision.

Cheers,

Kev.

[andrew63]

I've used both in the past. The nirvana was a bit more comfortable but the meade/maxvision was a bit sharper. 

 

andrew

[kev100]

Thanks Andrew, that's very interesting (I hadn't considered that the view would be less sharp in the Nirvana). Several reviews I've read of the Nirvana range have compared them favourably to TV Naglers ... even in faster scopes. I guess I'm just wondering whether the additional 0.2 degree in afov and slightly better eye relief will make a worthwhile difference (the Maxvision is already very good).

Kev

[andrew63]

I think the 82deg view is more immersive -  and it is noticeable Kev for more relaxed viewing. Those 16 SWA are regarded as little gems though.

andrew

[Louis D]

Here is Ernest's test bench review of the 16mm Levenhuk Ra, which should be the same optically.

Compare it to his review of the 16mm Nagler T5.  The Nagler is way better corrected, but you pay a premium for that.

Here's Ernests's review of the 16mm ES-68, which should be the same optically as your 16mm Maxvision.  Again, the correction tends to be better in it than in the 16mm UWA.

There's also the 15mm Celestron Luminos which is about the same to slightly better corrected than the 16mm UWA with better eye relief.

[John]

1 hour ago, kev100 said:

Thanks Andrew, that's very interesting (I hadn't considered that the view would be less sharp in the Nirvana). Several reviews I've read of the Nirvana range have compared them favourably to TV Naglers ... even in faster scopes. I guess I'm just wondering whether the additional 0.2 degree in afov and slightly better eye relief will make a worthwhile difference (the Maxvision is already very good).

Kev

I've used 3 of the UWAN / Nirvana's, the 28mm, 16mm and 4mm. I liked them a lot and thought that they were very close to Naglers in performance. I compared the 16mm UWAN (which is the same as a Nirvana) with a 16mm T5 Nagler that I had at that time and found little difference between them but the scope I was using was an F/6 rather than and F/4.7. The UWAN/Nirvana had a little more eye relief than the Nagler but the flexible eyecup of the Nagler vs the inflexible eyecup of the UWAN/Nirvana negated that really.

I found the 4mm Nirvana to be an excellent planetary / lunar eyepiece.

I hope your translator is good to see what Ernest thinks of them !

 

 

[Paul73]

The 16mm MaxVision is a little gem. I haven’t seen many sharper. You are unlikely to notice the difference whilst enjoying those wide wide views.

Paul

[John]

5 minutes ago, Paul73 said:

The 16mm MaxVision is a little gem. I haven’t seen many sharper. You are unlikely to notice the difference whilst enjoying those wide wide views.

Paul

I think Kev is looking for an even wider view though ?

 

[Paul73]

Sorry. Sloppy writing on my part. I meant that, even if the MaxVision is a tiny bit sharper, the overall experience of 82° viewing would win the day.

Paul

[Mark at Beaufort]

Kev are you thinking of the new designed Nirvana EP which retails at £85 at FLO?

[kev100]

16 minutes ago, Paul73 said:

Sorry. Sloppy writing on my part. I meant that, even if the MaxVision is a tiny bit sharper, the overall experience of 82° viewing would win the day.

Paul

Thanks Paul (and everyone else). The 16mm maxvision is indeed a top eyepiece, but the 68 degree fov does seem a bit tight to me these days. Also, using it is similar to using a monocle as the eye relief is so tight. 

[kev100]

1 minute ago, Mark at Beaufort said:

Kev are you thinking of the new designed Nirvana EP which retails at £85 at FLO?

yes  or perhaps holding off for a second hand SKywatcher branded one ...

Essentially, I'm looking for something to fill the gap between the 20mm myriad, and the 8.8 explore scientific ... but without breaking the bank.

[kev100]

3 hours ago, Louis D said:

Here is Ernest's test bench review of the 16mm Levenhuk Ra, which should be the same optically.

Compare it to his review of the 16mm Nagler T5.  The Nagler is way better corrected, but you pay a premium for that.

Here's Ernests's review of the 16mm ES-68, which should be the same optically as your 16mm Maxvision.  Again, the correction tends to be better in it than in the 16mm UWA.

There's also the 15mm Celestron Luminos which is about the same to slightly better corrected than the 16mm UWA with better eye relief.

Google translate did a fair job of translating Ernest's reviews, and the conclusion re the Nirvana is :

"Eyepiece looks very personable. It has a huge 82-degree field of view, which, combined with a 16 mm focal length, makes it an excellent candidate for a viewing eyepiece for a 1.25 "eyepiece tube. But ... the image quality at the edge of the field of view of this eyepiece is poor. I think the best application is could be found in telescopes with a relative aperture of 1: 12-1: 15, such as the compact Maksutov-Cassegren. The high-aperture optics is contraindicated for him."

I feel this rules it out for me and my scope, and I think I'll hang on to the MaxVision for a while. 

Cheers all,

Kev

[Louis D]

1 hour ago, kev100 said:

Google translate did a fair job of translating Ernest's reviews, and the conclusion re the Nirvana is :

"Eyepiece looks very personable. It has a huge 82-degree field of view, which, combined with a 16 mm focal length, makes it an excellent candidate for a viewing eyepiece for a 1.25 "eyepiece tube. But ... the image quality at the edge of the field of view of this eyepiece is poor. I think the best application is could be found in telescopes with a relative aperture of 1: 12-1: 15, such as the compact Maksutov-Cassegren. The high-aperture optics is contraindicated for him."

I feel this rules it out for me and my scope, and I think I'll hang on to the MaxVision for a while. 

Cheers all,

Kev

You can actually interpret his measurements for yourself as well if you're cross shopping various options.  For example for the 16mm UWA in question:

Residual aberrations of the eyepiece

With a 1: 4 lens. Good in sharpness and contrast, the image on the axis with an aberration spot of less than 4 ang. minutes On the zone (70% from the center of the field of view to the edge) the image of the star increases in size to 20 angles. minutes due to the curvature of the field of view. At the edge (one and a half degrees from the edge of the diaphragm), the aberration spot has due to astigmatism and curvature is pulled into a sagittal line with a length of 55 angles. minutes Moderate magnification chromatism stains blue inside edge of the luminous line. There is a moderate (4-5%) positive distortion.

With a 1:10 lens. Field aberrations are reduced to 8 angles. minutes on the zone and 20 ang. minutes at the edge.

What this means is that with a well corrected f/4 lens, as the eyepiece input field is scanned across the axis of the lens (to eliminate edge of field aberrations inherent in the lens), the test spot (artificial star) is measured at various points across the field.  On axis, it shows as 4 angular minutes across, which is very good.  2 minutes or less is exceptional.  His second measurent, "on the zone" is 70% of the way to the edge (30% away from the edge).  In this case, 20 angular minutes, which is on the poor side, but not awful.  Very well corrected eyepieces tend to fall in the 8 to 12 angular minutes category.  Really bad are above 30 angular minutes.  At the edge (1.5 degrees away from the field stop) is the third measurement he always takes.  This one is the acid test, and might not be that important to people who keep objects centered, especially in ultrawide to hyperwide eyepieces.  In this case, 55 angular minutes which is horrible.  Eyepieces fall into the poor category at 25 to 35 angular minutes.  Above 35, it's moving into bad territory.

The second paragraph is when an f/10 test lens is substituted for the f/4 and the process is repeated.  On axis probably is no worse than 4 minutes since it is not stated.  If it doesn't improve, he often won't mention it.  The 70% value drops from 20 to 8 which puts it into excellent territory.  At the edge, it drops from 55 to 20, which brings it squarely into the acceptable range.  Thus the takeaway that this eyepiece would work well in slower scopes like SCTs and Maks as he states in his summary.

By comparison, the 16mm Nagler T5's numbers at f/4 are "less than 6", 7.5, and 7, so very tightly controlled across the field.  At f/8 and f/11, basically the same.  At f/16, diffraction limited means the spot is basically as small as optical physics allow.  Compare 6:7:7 to 4:20:55 for the UWA at f/4 and 4:8:20 at f/10.  This means the UWA is possibly sharper on axis, and much worse off-axis in slower scopes.  In slower scopes, they're very similar out to 70%, and then the Nagler takes over to the edge.

I've noticed Ernest has been substituting an f/6 lens for the f/4 lens in his more recent tests.  I haven't discovered why.  Perhaps f/6 is more representative of the typical scope than f/4?

[rwilkey]

17 hours ago, kev100 said:

Also, using it is similar to using a monocle as the eye relief is so tight. 

Hi Kev, eye relief is a bit tight on all these ep's, that includes the ExSc (as you may have found on the 8.8mm, a lovely ep BTW) and the Naglers, the N16T5 is a particularly fine ep which I very much like and it is so compact. 

[kev100]

21 minutes ago, rwilkey said:

Hi Kev, eye relief is a bit tight on all these ep's, that includes the ExSc (as you may have found on the 8.8mm, a lovely ep BTW) and the Naglers, the N16T5 is a particularly fine ep which I very much like and it is so compact. 

Hi Robin,

The 8.8 is a cracker, and I definitely won't be parting with it, even though the eye relief is tight. The 16mm maxvision, though, does feel tighter, and I'm starting to find the FOV restricting. Budget can't run to a T5, though

Kev

[John]

The eye relief on the Nagler T5 16 is 10mm which is a bit less than the T6 Naglers. I believe it's difficult to design short to mid focal length eyepieces with ultra / hyper wide fields of view that also have decently long eye relief - the lenses used would need to be massive and the resulting eyepiece heavy and expensive.

[Louis D]

58 minutes ago, John said:

The eye relief on the Nagler T5 16 is 10mm which is a bit less than the T6 Naglers. I believe it's difficult to design short to mid focal length eyepieces with ultra / hyper wide fields of view that also have decently long eye relief - the lenses used would need to be massive and the resulting eyepiece heavy and expensive.

Yep.  Witness the 17mm ES-92 and 17mm Nagler T4 (next to a 17mm AT AF70):

[kev100]

Thanks to everyone who has contributed to what has become a fascinating and informative thread. I guess my question now is: is it even possible to get a good 82 degree EP, for use in a fast scope, in the 14-16mm focal length range ? Without breaking the bank ? ....

[bingevader]

I have the 14mm Meade, which I believe is equivalent to the ES these days.

It's one of my favourites and sharp across the field of view.

[Louis D]

46 minutes ago, kev100 said:

 I guess my question now is: is it even possible to get a good 82 degree EP, for use in a fast scope, in the 14-16mm focal length range ? Without breaking the bank ? ....

Try to locate a good condition used 16mm Nagler T2?  They go for about $150 here in the states.

[John]

54 minutes ago, kev100 said:

Thanks to everyone who has contributed to what has become a fascinating and informative thread. I guess my question now is: is it even possible to get a good 82 degree EP, for use in a fast scope, in the 14-16mm focal length range ? Without breaking the bank ? ....

Well I would still argue that the Nirvana / UWAN 16mm would fulfil that. But clearly others don't agree

 

[Ags]

Looking at getting a Nirvana 16/82 for my ST80. I'll take you at your word @John ?

[kev100]

1 hour ago, bingevader said:

I have the 14mm Meade, which I believe is equivalent to the ES these days.

It's one of my favourites and sharp across the field of view.

What scope do you use it with?

[bingevader]

200p