Nirvana 13 or Explore Scientific 16?

[Ags]

I'm looking for an eyepiece to slot inbetween my ES 82° 6.7mm and ES 68° 20mm. I'm looking at either the Nirvana 82° 13mm or the ES 68° 16mm. I hear the ES 16 is very good, but the Nirvana 13 is a better spacing (not to mention the atractive price!).

I'd like to try the eyepiece in my f4 finderscope giving a 5.1° field with either eyepiece, but it would mostly be used on DSOs in my f5.6 refractor.

[Mr Spock]

I've not used any ES eyepieces, but I do know the Nirvana 13mm is pretty good. I quite like mine.

[Ags]

I have the ES 20 and previously the ES 24, and both are excellent.

[Kon]

How about the ES 14mm 82 degrees? I upgraded to it after the 15mm BST and it is an excellent EP. I also use it, mostly, for DSOs. Good correction to the edge. As you already know from your 6.7, it has a tight eye relief. They are on Aliexpress for ~£125 so not that much more than the Nirvana (I have no experience with it). I personally like the wide FOV when I observe nebulas/galaxies as it gives the immersion feeling, plus less nudging of the Dob.

[rwilkey]

I have all the ES 82º series, however, I bought a 16mm Nirvana clone (Telescope Service) recently second hand to compare it with the TV 16mmT5 and to be honest the Nirvana clone compared equally well with the TV.  I would recommend the Nirvana to anyone.  The FLO price is also very competitive.

Edited March 30, 2023 by rwilkey

[Ags]

2 hours ago, Kon said:

How about the ES 14mm 82 degrees?Good correction to the edge. As you already know from your 6.7, it has a tight eye relief.

I find the eye relief on the 6.7 just right for me, nice and snug but not too close.

7 minutes ago, rwilkey said:

I have all the ES 82º series, however, I bought a 16mm Nirvana clone (Telescope Service) recently second hand to compare it with the TV 16mmT5 and to be honest the Nirvana clone compared equally well with the TV, if a little lighter.  I would recommend the Nirvana to anyone.  The FLO price is also very competitive.

I have heard that from several people, but I have owned the Nirvana 16 and while it gave many enjoyable views, particularly of the Moon, I ultimately found its edge correction, curvature and astigmatism unbearable. My sources tell me those issues do not affect the Nirvana 13 however!

Edited March 30, 2023 by Ags

[rwilkey]

10 minutes ago, Ags said:

I have heard that from several people, but I have owned the Nirvana 16 and while it gave many enjoyable views  particularly of the Moon, I ultimately found its edge correction, curvature and astigmatism unbearable. My sources tell me those issues do not affect the Nirvana 13 however!

Interesting, that has not been my experience with the TS UWA "UWAN" 82 degree 16mm. 

Edited March 30, 2023 by rwilkey

[Mr Spock]

22 minutes ago, Ags said:

I ultimately found its edge correction, curvature and astigmatism unbearable. My sources tell me those issues do not affect the Nirvana 13 however!

Exactly what I found. The 16mm has field curvature at the edge; the rest of the range are all sharp to the edge.

[Mr Spock]

When I'm observing doubles, I skip the 16mm (and 10mm) as the range 30mm UFF then Nirvana 13, 7, 4 is a really good progression.

[Moonlit Knight]

I am a big fan of Explore Scientific eyepieces. I own the 14 mm and have owned the 16mm. Both excellent eyepieces. It all depends on your scope I guess, but I love the 82 degree series and heartily recommend them. The 4.7 and 6.7 are staggeringly good planetary eyepieces. 

[Moonlit Knight]

ES build quality is also superior Nirvana 

[Louis D]

What's wrong with the Speers Waler 13.4mm in your signature?

[Ags]

Optically the Speers WALERs are great. Just very long and awkward. I prefer the ergonomics of the 6.7.

[Louis D]

6 hours ago, Ags said:

Optically the Speers WALERs are great. Just very long and awkward. I prefer the ergonomics of the 6.7.

I guess it comes down to optical pickiness versus budget.  The TV NT6 13mm would seem to tick all the boxes except for price.

At that focal length in 1.25", I really like my APM Hi-FW 12.5mm.  However, it's probably too large and heavy for your intended use case(s).

[Ags]

Yes NT6 13 would be ideal, but far out of my budget sadly. Realistically, I think it will be the OVL Nirvana 13 as FLO have such a good price. I'll do a comparison to the Speers WALER 13.4 and decide which I want to keep. If I can pick up a second-hand ES 14mm then I might go that route instead.

The goal is this widefield progression: Nirvana 4mm >>> ES 6.7mm >>> Nirvana 13mm >>> ES 68 20mm.

I don't have the Nirvana 4 yet either, I might get the ES 4.7 instead.

I don't go above 20mm in the progression because of local light pollution ruining the views at exit pupils above 3mm. For dark sky trips I might add an ES 62 26mm however.

Edited March 31, 2023 by Ags

[Ags]

Ok, still thinking and now being heavily influenced by FLO's option to pay in three installments. The new plan is:

ES6.7/82 >> ES11/82 >> ES16/68 >> ES20/68

SVB3-8 >> SLV6 >> SLV12 >> SLV25

I'm dropping the Nirvana 4mm as every application for it is covered better by the Svbony 3-8 zoom (maybe first light on that tonight). I hear the ES 14/82 suffers from field curvature, which is a problem for my eyes, so I am going for the ES 16/68. Because I am going for a 16 and not a 13, I will include the ES 11/82 to bridge the gap to the 6.7mm.

I am also picking up some more SLVs for a 6/12/25 doubling progression for those nights where I want a more retro plossl-like view. With an x3 telecentric, the SLVs give a high power progression of 2/4/6/8.

[Zermelo]

2 hours ago, Ags said:

Ok, still thinking and now being heavily influenced by FLO's option to pay in three installments. The new plan is:

ES6.7/82 >> ES11/82 >> ES16/68 >> ES20/68

SVB3-8 >> SLV6 >> SLV12 >> SLV25

I'm dropping the Nirvana 4mm as every application for it is covered better by the Svbony 3-8 zoom (maybe first light on that tonight). I hear the ES 14/82 suffers from field curvature, which is a problem for my eyes, so I am going for the ES 16/68. Because I am going for a 16 and not a 13, I will include the ES 11/82 to bridge the gap to the 6.7mm.

I am also picking up some more SLVs for a 6/12/25 doubling progression for those nights where I want a more retro plossl-like view. With an x3 telecentric, the SLVs give a high power progression of 2/4/6/8.

I also have the ES 6.7mm 82°, and the Nirvana 4mm and 16mm. The ES is sharp, though the targets can sometimes be dim in my small-aperture scopes. I find the Nirvana 16mm to be more comfortable to use, and it gives very nice, contrasty views of open clusters in particular. The arrival of the Nirvana 13mm came after I acquired a second hand Morpheus 14mm, otherwise I would certainly have bought one.
I don't like the Nirvana 4mm as much as the 16mm. It can produce some very nice views in good conditions, but it seems susceptible to atmospherics in a way that I can't rationalize. If you already have the Svbony 3-8 zoom then I would stick with that - in my experience so far, it outperforms the (my?) Nirvana 4mm.

[Don Pensack]

3 hours ago, Ags said:

Ok, still thinking and now being heavily influenced by FLO's option to pay in three installments. The new plan is:

ES6.7/82 >> ES11/82 >> ES16/68 >> ES20/68

SVB3-8 >> SLV6 >> SLV12 >> SLV25

I'm dropping the Nirvana 4mm as every application for it is covered better by the Svbony 3-8 zoom (maybe first light on that tonight). I hear the ES 14/82 suffers from field curvature, which is a problem for my eyes, so I am going for the ES 16/68. Because I am going for a 16 and not a 13, I will include the ES 11/82 to bridge the gap to the 6.7mm.

I am also picking up some more SLVs for a 6/12/25 doubling progression for those nights where I want a more retro plossl-like view. With an x3 telecentric, the SLVs give a high power progression of 2/4/6/8.

At 1500mm focal length, having a 20mm (75x) and a 16mm (94x) results in two magnifications only 19x apart, likely too close to be useful.  You would likely use one or the other, but not both.

In the shorter focal length scopes, the magnifications will be even closer together.

11mm to 16mm is a reasonable square root of 2 increase.  Extend that from 16mm and your next magnification should be a 22-23mm, not 20mm.

There are some wonderful and inexpensive 22mm eyepieces (like the Omegon Redline) out there, but they are 2".  If your scope takes only 1.25", you might look at the ES 24mm 68° or the APM Ultra Flat field in 24mm.

Both would yield much larger true fields than the 25mm SLV. 

[Ags]

The ES 20/68 is a compromise eyepiece, offering the widest 1.25” field with a usable exit pupil given my light polluted sky. I had the 24mm variant but it wasn’t great as the sky background was too milky ( bear in mind the C6 is usually used with an f6.3 reducer). I expect the 16mm to be used more often on more targets, simply because the exit pupil is slightly better and the field is still wide enough for most targets.

The SLVs are for sentimental reasons; they don’t obey the rules of logic  The SLV 25, aside from sentimental viewing, is really for my solar scope as an alternative to the 30 mm plossl I usually use.

Edited April 7, 2023 by Ags