Radian 8mm vs Vixen LVs vs barlow Meade UWA

[michael.h.f.wilkinson]

Recently I got a Radian 8mm for planetary work to replace one or both LVs I have had for some years. And lo and behold, I have been able to have a good look at Mars and the Moon with them, to see how they compared. Now my scope is an F/10, so it does not put any EP to the strictest test, so I was wondering how much better the results would be with the Radian.

I first has a shot at Mars, which was quite high in the sky at that point. I first used the Nagler 22mm T4 to find Mars, and instantly saw detail. The Meade Series 5000 14mm UWA (at 143x) showed more detail, and the 9mm LV gave a crisp image at 220x, with good seeing. The AFOV of 50deg did seem very constricted when compared to the Nagler and UWA at 82deg, but the increased eye relief is nice, even if the fold-back rubber eye-cups of the LVs are a pain to use: you cannot store them with the cup folded down because the dusk covers won't fit, and I cannot with the eye-cup folded up.

I then switched to the Radian at 250x. I was expecting a bit of a drop in brightness, but nothing of the kind. The image remained very crisp, showing a bit more contrast. The wider field (60 deg) is nice for planetary work, but perhaps not essential. It does line up better with the 82deg AFOV of the other EPs I use.

The Vixen LV 7mm was next, and the view was clearly a bit dimmer and a bit less sharp (maybe hitting the limit of the seeing) and its 45deg AFOV was a pain after the 60deg of the Radian.

I then started playing around with the three EPs a bit, switching a number of times, to carefully see the differences. My main conclusions are:

• In the centre of the FOV, the Vixens did pretty well, but their transmission and contrast seemed a bit lower. The Radian did outperform them, but not by a wide margin
  
• Towards the edge of the FOV (outer 20% I think), the Vixens clearly deteriorate, whereas the Radian stays sharp, despite its wider FOV.
  
• The eye-cup (instadjust) may not be to everyone's liking, but I like it a lot, especially the fact I can store my EPs with the eye-cup in the right position
  

The latter may seem a minor point, but a make a point of putting dust covers on EPs the minute I remove them from the scope, so the Vixens caused some irritation. In planetary work, I often switch magnification depending on variable seeing conditions, so a quick switch is much appreciated.

I also quickly tested the Meade UWA with a 2x Meade TeleXtender. Compared to the LV, it seemed to have a slight edge, if anything, but it did not look as crisp as the Radian, again, maybe due to seeing limitations.

I then tried all four on the Moon, and found similar results. Here the wider field of view, and better edge performance of the Radian clearly have the edge over the LVs, with the TeleXtender/UWA combination a close second (though first in terms of FOV). None of the EPs showed internal reflections, though there was a bit of glare in the LV 7mm, and slightly less so in the LV 9mm.

I would have liked to compare the Radian to e.g. an ortho, but for me the eye relief of the latter is not good enough. With rather strong astigmatism, even at this exit pupil diameter I prefer using glasses.

Bottom line: The LVs are nice EPs, I much prefered them to my older Celestron Plossl 10mm. They are generally well-built EPs, with only my complaint on the eye-cup. However, the Radian has them beaten on the edge performance in particular, even at F/10. As expected the build quality of the Radian is excellent. It is the best planetary EP I have used.

[John]

Nice report Michael !.

The Radian is the one Tele Vue eyepiece design that I've yet to try - looks like I'm missing out on something good

I think the LV's were considered excellent when they came on the scene and are still very competant eyepieces. It's just that things have moved on now in the world of eyepiece design so they have been overtaken a little by the use of the latest glass types and further improved multi-coatings - Tele Vue's are especially good in that latter department I find.

Thanks again for posting

[nicnac]

at last! a review of a Radian!

[michael.h.f.wilkinson]

Nice report Michael !.

The Radian is the one Tele Vue eyepiece design that I've yet to try - looks like I'm missing out on something good

I think the LV's were considered excellent when they came on the scene and are still very competant eyepieces. It's just that things have moved on now in the world of eyepiece design so they have been overtaken a little by the use of the latest glass types and further improved multi-coatings - Tele Vue's are especially good in that latter department I find.

Thanks again for posting

I think the LV are really good, and I had a lot of fun with them, but they have indeed fallen behind. They are now being replaced by the NLVs, I have yet to see reviews of them.

One thing I forgot to remark is that the Radian is so much cheaper than the Naglers in the same range, AND have a better eye relief, so I gladly forgo the 82deg FOV

[John]

One thing I forgot to remark is that the Radian is so much cheaper than the Naglers in the same range, AND have a better eye relief, so I gladly forgo the 82deg FOV

Radians = £170 Nagler T6's = £206 so cheaper but not much cheaper ?.

The Radian eye relief is 20mm wheras the Nagler T6 is 12mm so the Radian will certainly be preferred for those that wear glasses when observing.

I use undriven alt-az mounts most of the time and don't wear glasses so the extra field of view of the Nagler is valuable to me but all are great eyepieces

[michael.h.f.wilkinson]

Horses for courses of course. The Naglers have gone down quite a bit. I heard (but cannot confirm) that the Radian has a slight edge in transmission and contrast.