Vixen LVW or NLV

[MattT]

Hi Vixen eyepiece users,
I am wanting to finish my small eyepiece collection...if thats possible, and have boiled down my choices to NLV or LVW's. I'm wanting a 13, 8, 7 and 5 or thereabouts. For say a 5mm FL apart from the difference in FOV is there much of a difference in the image in brightness, contrast etc. I know I should look through these things at a star party but haven't yet. Not sure which way to jump My other reasonable eyepieces are ES 68 degree 20 and 16mm. Was thinking of adding some 82 degree series, maybe I should, but some reviews are not so favourable. DSO and Planets are on the viewing menu..
Thanks, Matt

[Wavytone]

MattT,

I'm a spectacle wearer and ultra-wide fields don't really do a lot for me, I'd much rather have lots of eye-relief and a very sharp contrasty image. The LVW's give 65 degree fields of view, the LV and NLV series give 50-52 degree fields. In my scopes the LVW 5, 8 and especially 13 are my favourites; in your Newtonian the 17mm would be fine too. I have these plus the 22mm and an NLVW30mm (I would suggest you don't buy this).

http://www.opticsplanet.net/vixen-lv-w-eyepieces.html
http://www.optcorp.com/productList.a...=30-718-76-813

I also have a set of LV's (LV5, 7, 10, 15 and 25mm) for my smaller refractor, they are very comfortable to use for long periods, high transmission and excellent contrast, little or no colour. The NLV's are the same glass but with a fugly fat plastic shroud.

At the long end I much prefer the TMB Paragon 30 or the Vixen LV50 (but its a 2" monster) over the NLVW30 which isn't so sharp, these are all fine on my 102mm f/7 refractor by they won't suit an f/5 Newtonian.

I have tried a couple of ES eyepieces and didn't like them so much.

[peter_4059 (Peter)]

I've got the LVW22 and LVW13 and the LV9, LV6 and LV4 that I use with the 10" newt. I've very happy with all of these. I went for the LV's instead of LVW's for the shorter focal lengths (higher mag) as I figured wider fields were not that important when you are trying to view a planet.

[allan gould]

I have the 40 to 5mm set of the LVWs. Best thing I've done as eye relief is excellent and I like the field of view

[traveller (Bo)]

Hi Matt,
I have three older LV's (as opposed to the New LV). As you are Melbourne based, just send me a PM if you want to borrow mine to try out.
I think they are great EPs, very sharp, great contrast.
Cheers,
Bo

[Profiler (Profiler)]

Hi Matt

All good comments and advice below but just be aware that a Vixen 7mm fl no longer exists in the NLV's and never existed in the LVWs (you can get a 8mm LVW instead if you prefer - a highly regarded EP). If you are set upon a 7mm Vixen you will need to hunt around in the 2nd hand market to find a 7mm LV - Don't ask me why Vixen discontinued this particular fl when producing the NLV's.

[mercedes_sl1970]

Hi Matt

I think the Vixen LVs are definitely an under-rated eyepiece, well at least for the two I had - 5mm and 9mm (now not available). In the endless eyepiece quest I parted with them... I now have the LVW 5mm which I am very happy with. It seems to be well-corrected, has good transmission, very sharp, has a neutral colour and the views just seem to sparkle.

Andrew

[MattT]

Thanks for the replies,
All this helps me to go the NLV direction. Eye relief is high on the agenda as I've just got to the big 50 Also my favourite scope is a 6" refractor at f8, and Wavytone your comment on not wanting a large field of view strikes a chord with me.
Bo, if there is ever another good viewing night ...I'll Pm you and take you up on that kind offer ...wow what a great bunch

Allan ,Peter and Andrew thanks for your advice will eventually go for a mixture of the two types , got to admit the ES eyepieces are not as good as the hype but nice all the same. Suppose you get what you pay for. At least they were on sale Matt

[Wavytone]

Maybe some LV's here, incl 7mm
http://www.william-lt-ng.com/Tats_home.htm
Check the used equipment link.

[bytor666]

I would recommend the Vixen / Orion LVW's as well. Plenty of eye relief and excellent central & edge correction right down to f/4. Great eyepieces IMHO.

Cheers,

[brian nordstrom (As avatar)]

Yep, another vote here for the Vixen LV's , mine are perfect when used in all my refractors , so easy to use , they just get out of the way and let you see all there is to see ,
As said before , these are very under rated eyepieces .
You cant really go wrong .
Brian.

[madbadgalaxyman (Robert)]

I have a Vixen 22 mm LVW, which is a nice eyepiece, but I have to say that the Hand Grenade Sized super-heavy-weight 20 mm type II nagler, now a collectors item, beats it by a mile. (This "big kahuna", that weighs as much as a telescope counterweight, is so highly regarded that it still costs a small fortune, even on the second hand market)

Usually, I would say that Super Premium eyepieces like the Naglers are a luxury, compared to Good Quality lower priced eyepieces, but the views through the old 20 mm Type II Nagler do make the 22mm LVW seem like a toy, in comparison to the Nagler.

To me, the Vixen 65 degree field eyepieces have always seemed overrated, considering their high price.....there are plenty of cheaper eyepieces that give views every bit as good.

[bytor666]

You won't find hardly any cheaper eyepieces that will give you excellent edge correction down to F/4 than the Vixen LVW's....good luck with that!

Cheers,

[madbadgalaxyman (Robert)]

The issue of how to accurately compare the edge correction of various eyepieces , when used with short focus scopes, is important. Anyone got any suggestions as to how to evaluate this in a rational and non-subjective manner?

[bytor666]

All one needs to do is a Google search or search on Cloudy Nights for many reviews about this issue. I myself have tested hundreds of eyepieces from F/4.72 right up to F/6 using the eyepieces in their native form and with many different barlow lenses. My next purchase will more than likely be a Paracorr, which is needed IMHO with my 10" F/4.72 reflector for better edge correction on some of the eyepieces I have now.

The Vixen / Orion LVW eyepieces have been evaluated extensively down to F/4. Here is the translated site below. If you scroll down near the bottom, the LVW evaluations are there.

http://www.svenwienstein.de/HTML/hyp...h_version.html

Cheers,

[Wavytone]

Originally Posted by bytor666

http://www.svenwienstein.de/HTML/hyp...h_version.html

There are better ways. But first you will ned to understand a little about the aberrations significant in most eyepieces. FWIW it is assumed here that the eyepiece you are considering gives a sharp image on-axis, i.e. it is achromatic, free of spherical aberration and free of wedge, and has been reasonably well assembled. Anything that shows these problems on-axis belongs in the bin.

1. Axial spherical aberration at the exit pupil.

This causes the 'kidney bean' effect noticeable when the exit pupil is close to the same size as your eye pupil - quite noticeable on many low power eyepieces, it is often very annoying with reflectors with a central obstruction, less so in refractors. On short focal length eyepieces ASA is not a concern.

2. Field curvature - if it is a poor match to the field curvature of your scope, you'll always have part of the field focussed and another part unfocussed. Definitely a big issue, what works well on one scope may be a poor choice for another type of scope.

3. Monochromatic aberrations - distortion, coma and astigmatism off-axis. Distortion is only a nuisance. Coma and astigmatism are worse, producing winged shaped that will never focus. The net aberration you will see is the sum of the contribution from the eyepiece and the telescope, so like field curvature, an eyepiece that works well with Newtonians may not be such a good choice for others.

4. Lateral chromatic aberration (LCA) off-axis. Basically, a star is sharp on-axis but near the edge of the field it is smeared radially into a rainbow.

All eyepieces have all of the above to a greater or lesser extent. Worse, when you have a combination of field curvature, LCA coma or astigmatism, you will see some fairly disappointing results for stars near the edge of the field of view.

How to evaluate: Forget about testing on stars, its too awkward and too subjective, and stars are generally too dim to see what's really going on when they are near the edge of the field - you need a brighter test source.

Ideally you need an optical bench with the measuring gear to look into the eyepiece and measure what is seen, but I know none of you have that.

Next best is to use a distant bright light, or an artificial star consisting of a white LED or pea-torch bulb at about 1km range. Even better, use it's reflection off a ball-bearing.

[bytor666]

Been into astronomy for about 30 years now, so I am well aware that there is no free lunch. Testing on stars is fine....done that all of my life too. The eyepiece I was considering is very sharp ON AXIS as well as OFF AXIS. I really don't need to go on any further about this.

Cheers,

[Profiler (Profiler)]

Uh oh - here we go - the age old debate of whose largely Japanese made glass is better.

Wavytone - Very good explanation of EP properties/specs

[bytor666]

Debate? There is no debate, there never was, LOL! All I did was drop a link showing a test @ f/4, nothing more. JUst got back inside myself for an observing session, was fun indeed !

Have a great day / night!

Cheers,

[madbadgalaxyman (Robert)]

Thanks, bytor666 and Wavytone, for the excellent tips on non-subjective eyepiece testing. You have obviously compared enormous numbers of eyepieces, so your advice is much sought after in this forum.

I just bought a William Optics UWAN (ultra wide angle) 4mm, for use in my ED Doublet F6 4 inch apo (or, more correctly, semi-apochromatic) refractor.
Have you evaluated one of these eyepieces, and if so, what do you think of it?
(they are available in Australia, discounted, for about 200 Australian dollars)

People (such as myself, at present) who have just bought a shiny new eyepiece, often at great cost, naturally tend to have perceptual biases, with the natural human tendency being to overestimate the performance of that brand new eyepiece which may have been bought at great cost.