New Nirvana focal length - 13 mm

[Ags]

After years (decades?) of being an odd range with just 3 1.25" focal lengths - 4, 7 and 16 mm - the TS site is showing a 13 mm now. If anything the range is even odder now with 4, 7, 13 and 16. If I was going to add one focal length to the Nirvana range it would have been an 11 mm - halfway between the 7 and 16....

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p14477_TS-Optics-1-25--Ultra-Weitwinkel-Okular-UWAN-13-mm--82--Gesichtsfeld.html

I had the 16 mm for a while and loved it on some nights (fabulous views of the Moon) and loathed it on other nights - on those nights it was fuzzy and astigmatic off axis. My experience didn't chime with the general consensus of the eyepiece holding its own against the equivalent Nagler... Still, I toy with the idea of picking up another (maybe I was unlucky with my sample of one?), and getting the 4mm for my top magnification. 

I wonder how this 13 mm will fare?

Edited May 20, 2022 by Ags

[Louis D]

Astronomics has 10mm UWAs on order in their Astro-Tech house brand, so it is available from the manufacturer.  Perhaps someone on your side of the pond will order some in the near future.

[Voyager 3]

12 hours ago, Ags said:

After years (decades?) of being an odd range with just 3 1.25" focal lengths - 4, 7 and 16 mm - the TS site is showing a 13 mm now. If anything the range is even odder now with 4, 7, 13 and 16. If I was going to add one focal length to the Nirvana range it would have been an 11 mm - halfway between the 7 and 16....

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p14477_TS-Optics-1-25--Ultra-Weitwinkel-Okular-UWAN-13-mm--82--Gesichtsfeld.html

I had the 16 mm for a while and loved it on some nights (fabulous views of the Moon) and loathed it on other nights - on those nights it was fuzzy and astigmatic off axis. My experience didn't chime with the general consensus of the eyepiece holding its own against the equivalent Nagler... Still, I toy with the idea of picking up another (maybe I was unlucky with my sample of one?), and getting the 4mm for my top magnification. 

I wonder how this 13 mm will fare?

There is a Omegon version of the 10mm in TS.

https://www.teleskop-express.de/shop/product_info.php/info/p13051_Omegon-Eyepiece-Oberon-10-mm---82--Field---1-25--Barrel.html

 

 

 

[Ags]

Is it really the same optically? The aesthetics of the Omegon do not appeal to me 😀

[Louis D]

6 hours ago, Voyager 3 said:

There is a Omegon version of the 10mm in TS.

https://www.teleskop-express.de/shop/product_info.php/info/p13051_Omegon-Eyepiece-Oberon-10-mm---82--Field---1-25--Barrel.html

Nope, those are the same as the Celestron Luminos line, just with the 31mm labelled 32mm.

[Ags]

13 hours ago, Louis D said:

Astronomics has 10mm UWAs on order in their Astro-Tech house brand, so it is available from the manufacturer. 

Ah, now it makes sense 4, 7, 10, 13, 16, gaps of 3!

[Paz]

I don't know why some eyepiece lineups have oddities. Vixen SLVs being an example. The top and bottom of the range make more sense but the range in the middle goes 12, 10, 9, 6! I wonder why the gap from 9-6 and why there is a 9 and there isn't an 8?!

[Louis D]

There used to be a 7mm LV that didn't get carried forward to the NLV and SLV lines for unknown reasons.

[Whistlin Bob]

Funnily enough my Nirvana experience is similar. I have the 4mm and on most targets it's a bit meh. However, on steadier nights, lunar views in an 8 inch dob are simply breathtaking. The textures and subtleties that it reveals on the lunar surface at 300x are just gorgeous.

A summer evening in my shirtsleeves and half a moon with a dob packing a 4mm nirvana is just about astronomy perfection, improved only with the addition of a cool beer. If you do take the nirvana plunge again, I hope it gives you some moments like that!!! 

[Zermelo]

I'm finding this thread very interesting.

I have the Nirvana 4mm and 16mm. I find the 16mm performance to be very even over multiple observations in different conditions, but the 4mm is different. I regularly compare it with a BST 5mm, and it seems to lose and win in equal proportions. In particular with regard to the light scatter, which seems to go one way or the other with no consistency.

[Zermelo]

16 hours ago, Paz said:

I don't know why some eyepiece lineups have oddities. Vixen SLVs being an example. The top and bottom of the range make more sense but the range in the middle goes 12, 10, 9, 6! I wonder why the gap from 9-6 and why there is a 9 and there isn't an 8?!

 

18 hours ago, Ags said:

Ah, now it makes sense 4, 7, 10, 13, 16, gaps of 3!

 

Previous threads have argued for selecting the focal lengths of eyepiece ranges either in terms of the magnifications achieved or the resulting exit pupil sizes. It has been argued that a good scheme is to have the steps between adjacent sizes increase/decrease by 40%, i.e. a geometric, rather than arithmetic, progression (same principle as with camera F-stops, each gives approximately double/half the light as the last)

This can be achieved for both magnification and exit pupil size by applying the same 40% ratio (x1.4) to the focal lengths of adjacent eyepieces. The actual numbers you get depends of course on where you want to start, but some examples relevant to the ranges discussed above might be:

4,  5.6,  7.8,  11,  15.4,  21.5

5,  7,  9.8,  13.7,  19.2 

rounded to 1 d.p.

 

The actual % changes for the ranges mentioned are:

Astronomics UWA 4, 7, 10, 13, 16  gives  75%, 43%, 30%, 23%

Vixen SLV  2.5, 4, 5, 6, 9, 10, 12, 15, 20, 25  gives  60%, 25%, 20%, 50%, 11%, 20%, 25%, 33%, 25%

both of which vary quite a lot in terms of the adjacent ratios.

 

Compare these with the ES 82 degree (original) range, having:  4.7, 6.7, 8.8, 11, 14, 18, 24, 30 giving  43%, 31%, 25%, 27%, 29%, 33%, 25%

and the Pentax XW 1.25" series, being closer still:  3.5, 5, 7, 10, 14, 20  giving 43%, 40%, 43%, 40%, 43%

 

Of course this relates just to selecting a range of focal lengths in abstract, and ignores the focal length and aperture of the OTA, the observing conditions, characteristics of targets, etc., all of which may affect the actual choice of eyepiece focal lengths in practice:

 

[Ags]

I arrange my own eyepieces on the 1.4x rule, which is also why I thought they would add an 11 mm not a 13 mm. But my OCD is pacified by the fact that Nirvanas now have some kind of mathematical progression, albeit linear.

[Louis D]

3 hours ago, Zermelo said:

the Pentax XW 1.25" series, being closer still:  3.5, 5, 7, 10, 14, 20  giving 43%, 40%, 43%, 40%, 43%

The original Pentax XLs were 5.2, 7, 10.5, 14, 21, 28, and 40mm.  Thus, every other was a doubling in FL (almost for the 40mm, should have been 42mm) or roughly 1.4x between adjacent eyepieces.  For years, I just used their 5.2mm and 14mm along with a much cheaper Rini 38mm MPL.  Then my eyepiece collecting started in strongly about 12 years ago.  That's about the same time my disposable income started jumping upward after the Great Recession.

[bingevader]

7 hours ago, Zermelo said:

Of course this relates just to selecting a range of focal lengths in abstract, and ignores the focal length and aperture of the OTA, the observing conditions, characteristics of targets, etc., all of which may affect the actual choice of eyepiece focal lengths in practice

This is what always intrigues me about these EP ranges.

I have EPs that suit my needs.

I have more at the shorter focal length end of things, because the resulting magnification and the difference between EPs is greater.

I have the 4mm and 7mm Nirvanas and they have always been very good to use in my 8" 'scope.

[DeanCJ]

I know this is a bit of an old thread now, but the 13mm and 10mm nirvanas are now available in the UK, they are listed on OVL UK website and showing in stock at Harrisons. Prices are in line with the rest of the range. I assume @FLO and other retailers will have them in stock or will have them soon. 
My wife and I have the 16mm and we use it with a 8” f10 SCT and a 4” f7 ed frac. We find it works very well with these scopes, and will be waiting patiently for reviews of the 13mm as I am considering this focal length for the SCT with M13 in mind. 

[FLO]

59 minutes ago, DeanCJ said:

Prices are in line with the rest of the range. I assume @FLO and other retailers will have them in stock or will have them soon. 

Indeed we will. Stock ETA is 2-4x working days 🙂 

Nirvana-ES UWA-82º Ultrawide Eyepieces

HTH

[Ags]

I want them all!!!!!!!!

[Ricochet]

I think these additions probably make these the standard recommendation for anyone looking for a £100 eyepiece. 

[Zermelo]

6 minutes ago, Ricochet said:

I think these additions probably make these the standard recommendation for anyone looking for a £100 eyepiece. 

They are well priced for what they offer.   I'll be interested to see reviews of the two new ones.

[Mr Spock]

I'm thinking about a 16mm and a 10mm. I don't have any really wide eyepieces anymore and the Naglers are stupid expensive - £398 for the 16mm as opposed to £89 for the Nirvana. I'm sure they aren't more than four times better, especially for my intended 'casual' use.

[Louis D]

2 hours ago, Mr Spock said:

I'm thinking about a 16mm and a 10mm. I don't have any really wide eyepieces anymore and the Naglers are stupid expensive - £398 for the 16mm as opposed to £89 for the Nirvana. I'm sure they aren't more than four times better, especially for my intended 'casual' use.

Here's Ernest in Russia's review/test of the 16mm Levenhuk Ra version.  He briefly mentions the 16mm NT5 and has a photo of them side-by-side.

[ScouseSpaceCadet]

The 16mm Nirvana is one of my favourite eyepieces. I see absolutely no need to change it. A solid performer in all the telescope variants I've had. Likewise the 7mm. In the 4" refractor the 7mm is my goto lunar eyepiece. The 4mm was as previously described, great on occasion but other times just 'meh'. It was replaced by a 4mm SLV. What I lost in fov I gain in overall clarity, contrast, better edge correction, a more comfortable eye position, strangely less floaters, less light scatter, no vignetting and less dewing. Strangely again, none of those drawbacks seem to apply to the 7 and 16mm... 🙄

The 10mm Nirvana is definitely tempting. I'll hang on for a review or two. 

 

Edited September 15, 2022 by ScouseSpaceCadet

[Ags]

I couldn't understand my N16 - It was great on some nights and appalling on others. It got so confusing I sold it. I am thinking of buying a new one...

Edited September 15, 2022 by Ags

[Mr Spock]

With my x2.5 Powermate, the 16mm and 10mm in the 102mm gives x45, x71, x112, x179. An even x1.6 progression between each magnification. And of course the x45 covers 1.84°. I think the Pleiades is going to look fab in that.

I think I've just convinced myself those two are perfect for my needs.

[Mr Spock]

Done. I'll do a full review of them once they arrive and get some use 👍