Vixen SLV Eyepiece Report: 6mm, 12mm and 20mm

[John]

Vixen SLV Eyepieces: 20mm, 12mm and 6mm

Firstly I ought to apologise for the fact that i) this report has been some time coming and ii) that it’s not as long and thorough as some of the excellent reviews that have been posted by others recently. Nevertheless I hope it’s of some interest for anybody interested in these new Vixen eyepieces. I also hope I've got the history of these eyepieces correct - please let me know if you spot any bloopers and I'll gladly amend the piece 

Around about 1994 Vixen introduced a range of eyepieces that were a notable departure from the more normal orthoscopic, plossl and erfle designs in that they contained as many as 7 lenses, had a consistent and comfortable 20mm of eye relief and used exotic Lanthanum glass for some of the lenses. That range was called the Vixen Lanthanum LV and they rapidly became very popular despite their relatively high price tag and the fact that they resisted pursuing the wide and ultra wide apparent fields of view that Tele Vue and Meade had embraced with such enthusiasm with the Vixen LV’s sporting a modest 45 degree apparent field of view.

The original Vixen LV range went all the way from 2.5mm to 40mm in the 1.25” fitting and also included a 2” format 30mm with a 60 degree field of view and finally a 50mm eyepiece. There was also an 8mm – 24mm zoom which was sufficiently good for Tele Vue to ask Vixen to re-brand a version for them. The Vixen LV’s received, and still receive very positive reviews and seemed to be owned and used by some pretty discerning amateur astronomers. They also proved very popular with those who wear glasses when observing as the high quality but moderate field of view was easily accessible to them due to the generous eye relief.

Fast forward to late 2007 and Vixen produced the first re-vamp of this successful range in the shape of the Vixen NLV range which clad a similar (though not identical) optical design in a more modern looking body which incorporated a two position, twist and click, eyepiece top section and integrated eyecup to make finding the correct eye position more consistently easier. The NLV range covered a similar range of focal lengths to the LV range although the 30mm in the 2” format was dropped and the 50mm 2” had a body shape all of it’s own. The 1.25” NLV’s from 9mm and 25mm inclusive had gained 5 degrees of apparent field of view as well.

It could be said that the NLV range was a careful and thoughtful evolution from the LV range, rather than a major step change, and I feel that the new Vixen SLV range, introduced in late 2013, introduces a similar further set of subtle improvements to an already excellent product. A further change is that the SLV’s are manufactured for Vixen in China rather than in Japan.

In an earlier post here: http://stargazerslounge.com/topic/211409-vixen-slvs-photos/ I described the physical attributes of the three Vixen SLV eyepieces that First Light Optics have been kind enough to lend me to try out, the 20mm, 12mm and 6mm focal length units. Since I’ve been using the eyepieces I’ve noticed that the twist up eyecup of the 6mm is a little looser in feel than that of the 12mm and 20mm.

I’ve had a number of sessions with these eyepieces over the past couple of months, in combination with my 12” F/5.3 dobsonian scope and my 4” and 4.7” ED refractors. Initially during this period the Moon was a factor in the sky so I was limited to planetary, lunar and binary star observations but on later occasions I was able to view some of the better known galaxies, nebulae and star clusters.

I usually wait until I have had a few sessions with an item before posting any performance reports on it however I was so impressed with the view through the SLV 6mm when I had first light with it that I broke this rule and posted a short exclamation on the forum: 

http://stargazerslounge.com/topic/209170-vixen-slvs-now-available/?p=2253493

The 6mm seems to match the performance of the Baader Genuine Orthoscopic 6mm very closely and is perhaps a touch better on Mars and Jupiter than my Ethos 6mm showing just a little less light scatter and the contrast of the surface features is just a little more clearly defined. The subtle colour tints stand out as well as I have seen in any eyepiece.  

One of the toughest tests I know of for a high power eyepiece is to try and see Sirius B, the faint and challenging companion to the brightest star in the sky. My 12” dobsonian will show the “B” star but only under steady viewing conditions and when an eyepiece with excellent sharpness and control of light scatter is used. The 6mm Vixen SLV proved as good as the Baader Genuine Ortho at this task which is high praise because the 6mm BGO was, up to now, the best eyepiece I’d found for this.

The only issue I've come across with the 6mm is some very slight pin cushion distortion right at the edge of the field of view. The effect of this is that Mars and Jupiter just start to elongate a little in the last few seconds as they drift towards the field stop edge, before disappearing behind it. This is a minor issue I feel though and it was a few sessions before I noticed it and only then when I was deliberately looking to see how the eyepiece performed right across it’s field of view.

Having seen this in the 6mm I looked carefully at the edge of field performance of the the 12mm and 20mm SLV’s but they don't show this effect.

This performance was consistent in all the scopes I tried the eyepieces in and the colour tint of the Vixen SLV’s seems very neutral, reminiscent of the Pentax XW’s which are another favourite eyepiece of mine.

With my scopes, the 12mm Vixen SLV is a medium power eyepiece giving between 55x in my 4” refractor and 133x with my 12” dobsonian. I found it an excellent eyepiece for viewing planetary nebulae, globular clusters and galaxies. It showed the supernova SN214J that was in the galaxy Messier 82 earlier this year very well indeed and, in the 12” scope, impressive structure and contrast variation in the galaxy too.

The challenging E & F stars in the Trapezium in Messier 42, the Orion Nebula were clearly picked out even with my 4.7” refractor at 75x with the great nebula itself spreading it’s bat-like wings around the cluster.

The 20mm SLV mirrored the optical quality that the 6mm and 12mm displayed including maintaining sharply defined stars across the whole field, even in my F/5.3 dobsonian.

Overall I’d say that the views given by the SLV’s are of similar quality to either a Pentax XW with 20 degrees less apparent field of view or a quality orthoscopic such as the Baader GO or Astro Hutech but with 8 degrees more field and a lot more eye relief, depending on which way you want to come at it.

In the 3 focal lengths that I had on loan the SLV eyepieces are nearly but not quite par focal so a small adjustment to focus is needed as you swap between them. Just a quarter turn or so of the focuser knob though, so nothing drastic.

I feel the Vixen SLV’s are excellent eyepieces for the observer that does not wish for wider fields of view and who is prepared to pay a little more for a 50 degree eyepiece which delivers top quality performance and comfortable viewing in a relatively compact but well made package. They should prove comfortable for those who wear glasses when observing too.

I've included below some more photos of the 3 eyepieces I've had on loan with a Baader Genuine Orthoscopic 6mm for scale.

Many thanks to First Light Optics for the loan of the 3 Vixen SLV eyepieces   

[Chris]

Thanks John, a great report of a range of EP's I've been curious about for a while. All I can say is wow, if they deliver BGO type views in comfort then they are surely going to be a winner! I have a set of Circle T's for the quality of view and a set of BST's for there comfort, the SLV's seem to combine these attributes in one eyepiece at a reasonable price - nice one Vixen!

Chris

Edited May 31, 2014 by starfox

[YKSE]

Nice work John, SLVs seems to be good planetary EPs for spec wearers.

[Mr Spock]

I'm quite happy with my NLVs, though I'd like to try one of these sometime.

[avtaram]

Good report John. I'm looking for a 6mm eyepiece for my 12" f5 Dob, this might just be what I need.

Avtar

[Jim Steele]

Nice work John, I'm really tempted by these. BGO quality in a more comfortable to use package sounds very attractive

[Damo636]

Thanks for the report John, the SLV sound very impressive indeed!

[Pig]

Excellent report as always John, some very valuable and useful information   My experiences with the SLV's have been excellent thus far.

I have often wondered how they would perform in a faster setup and it is pleasing to know they will hold their own in an F5

[Paul73]

Thanks for the report.

I took a punt and got the 6mm and am happily impressed with the views, comfort of use and the build quality.

All I have to compare against is the BST which didn't stand much of a chance (albeit at half the price), so it is good near the voice of experience giving them the thumbs up.

Paul

[alan potts]

As always an excellent piece of work and a very good early morning read, 4.30 am your time. It may be tempting to pick one of these up next time I am in England as I don't appear to be able to get them here without a lot of messing with different currency.

Alan

[Mark at Beaufort]

John a very enjoyable read and quality information as always. I recall at SGL9 you had these EPs with you and I thought that they looked a quality EP. at the time.

[John]

John a very enjoyable read and quality information as always. I recall at SGL9 you had these EPs with you and I thought that they looked a quality EP. at the time.

Thanks Mark (and to everybody else for the encouraging comments) 

I did have them at SGL9 and we did have a quick peek through one. Everything was a "quick peek" at SGL9 though !

On interesting little snippet I've picked up elsewhere is that there has apparently been a recent big price hike in low dispersion glasses such as Lanthanum when it's imported to Japan. It's cost has remained more reasonable in China though which might be a reason why the SLV's are made there now rather than Japan where the earlier LV and NLV ranges were manufactured. I guess labour and other production costs in China are lower as well so there are probably a number of factors at work here. 

Quality does not appear to have suffered though as I had the opportunity to compare the 6mm SLV with a Japanese made 6mm LV recently and the SLV was as good on all counts and rather better in terms of FoV and light transmission, in my view. The "click stop" eye cup adjustment is an improvement over the rather stiff roll down eye cup of the LV too   

[michael.h.f.wilkinson]

The eyecup of the old LVs was really the only think I could find to fault them (I had the LV7 and LV9 for years). The SLV series seems very nice indeed.

[nicks90]

would you say these are optically on a par with the legendary televue plossls with some added benefites - such as better eye relief?

[Laurie61]

Very nice review, I think if I was putting together a selection of eyepieces today these would figure prominently on my list to try.      

[John]

would you say these are optically on a par with the legendary televue plossls with some added benefites - such as better eye relief?

Yes, definitely in my opinion. I've owned a couple of sets of TV plossls so I know and respect them well. 

[Mark at Beaufort]

Yes, definitely in my opinion. I've owned a couple of sets of TV plossls so I know and respect them well. 

For some time I have thinking of improving upon the 25mm Antares plossls which I use in my binoviewers. I thought about the 25mm TeleVue as being the best option but clearly these new Vixen really look the business and provide a quality EP.

I really must have a look at the 25mm to make sure that the main body is not too wide - I need to get my nose between them.

[John]

For some time I have thinking of improving upon the 25mm Antares plossls which I use in my binoviewers. I thought about the 25mm TeleVue as being the best option but clearly these new Vixen really look the business and provide a quality EP.

I really must have a look at the 25mm to make sure that the main body is not too wide - I need to get my nose between them.

Mark,

The bodies of the 3 SLV's that I have are all 50mm in diameter. The twist up eye cups are 48mm outside diameter. Hope that helps

What we need is a little piece of software which lets us input the nose width and eyepiece type proposed and then calculates the interpupillary range that would be available. I think "Binoconksim" would be a good name for this application 

[Mark in Macc]

I have a pair of 15 mm NLVs that I use in binos and they are just ok size wise. I think the bodies are a similar size to the SLVs. If you have a large conk, they might feel a bit crowded. 25 mm TV plossls are excellent though. They would be my choice, and are already.

[g0ibi]

Just ordered the 10mm SLV from FLO as I need to fill a gap between a 7mm and 14mm, good report John glad I ordered it!

[bomberbaz]

Just read this and I am very impresed with the write up plus other stuff I have read. Now I am trying not to allow myself to pursuade myself that I need a 9mm but so far I am loosing the arguement, hehe 

[spaceboy]

Thanks for the time writing the review John

[nightfisher]

John, very nice write up, thanks for taking the trouble to do this, they seem a tempting product

[bish]

I've been toying with the idea of getting the 5mm. The lack of fov may be a worthwhile trade off for good performance and comfortable ER. As Spaceboy has said, it's good for the rest of us that you take the time to review and write up your reports. Must be very time consuming!

[John]

Thanks for the feedback folks

I've been toying with the idea of getting the 5mm. The lack of fov may be a worthwhile trade off for good performance and comfortable ER. As Spaceboy has said, it's good for the rest of us that you take the time to review and write up your reports. Must be very time consuming!

I feel lucky to be loaned these nice things by FLO so writing up a report is no trouble. Getting enough starlight through them to form some opinions sometimes is though !