Planetary Eyepieces

Floyd (or anyone else wishing to chime in!),

I am looking to add some planetary eyepieces to my collection for lunar, solar and planetary work.

William Optics came out with the SPL line (3,6 & 9mm) for $319 for the set(wow!).

Pentax has the 3.5,5,7,10 & 14mm XW series, but they are $309 EACH! I haven't had the opportunity to use either line of these oculars. Any comments about experiences with these or any other planetary oculars? What would be the "Ultimate" lineup of 3, regardless of brand and price?

I am guessing you get what you pay for, but in my experience, WO doesn't put out junk...

Any personal observations/ opinions/ insights would be greatly appreciated! 8O

Steve Sands said:
William Optics came out with the SPL line (3,6 & 9mm) for $319 for the set(wow!).

I agree that WO generally puts out fine equipments, but their spl config says 7 elements in 4 groups, which is very odd for eyepieces being advertised as optimized for viewing the planets where simpler is usually better. If price is a major factor, then I would go with a good Ortho.

Hi Steve,
Well, this opens a real can of worms, but here goes.

I recently tested the finest quality Orthos ( Zeiss, Pentax ect.) and compared them to complex designs, Pentax XL, Radian and B@/TMB Planetary EPs.

While there were some differences in the coolness or warmth of the EPs, there was little difference in performance. But there was a huge difference in the eye relief which means comfort to me. There was also a huge difference in price.

The short eye relief of most Orthos and Plossls below 9mm in focal length, becomes a problem for me. They get dirty quickly and due to the small lenses, they are hard to clean. Eyelash oils and splashes of tears are the main problem here. The they seem to fog easily too when it is cold, I think due to the moisture from the eye.

Now, I am not saying that there might not be a slight edge from a Zeiss when compared to a Radian or other planetary EP, but I am saying that there is little difference in the perceived details. When I used the Moon and a certain crater for comparison, myself and the wife both stated that the Pentax and Radian both were as good or maybe better on axis than some of the Orthos, the BO Planetary EPs were similar with a much cooler look, with the Zeiss being on the pinnacle but by a very slight edge. All of these EPs showed the same minute details and none actually showed more than the other, just the hue was different. Now this was of course to my eye and my wifes.

So, the cost, comfort and ease of cleaning are all important to me. If there is little difference in performance then it is a choice of hue and ergonomics.

I have not used the WO EPs, but I suspect they will perform as well as a Planetary EP or a Radian or any good Ortho or Plossl, with perhaps some slight loss of throughput.

So, I think that the $106 for the WO EPs is probably a good deal. The BO Planetary EPs at $100 are a good deal as are the clones of these EPs being sold. The EPs are all somewhat different in their hue, which can have positive or negative effects on some planets such as Jupiter.

The question is, do you prefer a tight EP over a long eye relief EP? Do you want to buy EPs that cost $300+ for planetary use? Will you see an advantage with a $900 Zeiss over a $106 WO? 8)

Hey Steve,
I pretty much agree with what's already been said: the Pentaxs and all do a really great job for a really upper end price. If you can sacrifice the field of view, the plossls and orthos tend to work just as well. That said, I've found that the Antares Elite plossls work just as well for my eyes as the upper end plossls, at 3/4 of the price, less if you get them used here on Astromart. At the shorter focal lengths the Vixen Lanthanums are pretty nice, fairly sharp and bright, but with 20 mms of eye relief, and they can be had for about $60-$70, again, here on Astromart. Works for me, hope it helps you!

Hi Jim,

Thanks for the response. The problem I have with Plossls is the eye relief on EPs below the 9mm mark due to eyeglass use. I agree that the simpler designs should be the best for planetary work and I do have a set of the TV Plossls, but haven't found visual planetary nirvana yet!

I would strongly suggest you at least try the Brandons particularly if you have a long focus telescope. Even if you don't, if you couple them with the Brandon 2.4x Dakin barlow you will still probably find them to be outstanding. You'd have to check, but I'd presume they are still priced at about $200 each. They have a somewhat narrow field of view and are poor off axis, but are extremely sharp on axis with absolutely outstanding contrast. Vernonscope claims single layer coatings provide more contrast than multicoatings, and comparing the Brandons to many other multicoated eyepieces, something is responsible for the added contrast that I see. Note that the 8mm has no eye relief.

Despite their wide field design with a lot of glass, IME the Pentax XL's are also outstanding planetary eyepieces, particularly the 5.25 and the 7, but out of your current price range.

The TV plossls are as good as most people think they are and are relatively inexpensive. The TV barlow and the powermates mate with these eyepieces exceptionally well IME.

The UO orthos are also as good as people rave about, but come in two different flavors and visually are radically different. To my eyes the volcano tops are the better planetary eyepiece (more contrast) and the HD's are clearly better in deep sky (more light transmission). Both are outright inexpensive and probably the best bang for the buck out there.

I find the Type 4 Naglers to be very good planetary eyepieces, better than the other Nagler types by a wide margin for lunar/planetary.

Ralph Junius

Scott, I'm with Ed on this one. Theoretically, you are absolutely correct, but when I check with my eyes at the eyepieces, my Pentax XL's and Nagler Type 6's stand up well to everything I've looked thru from monocentrics all the way thru the 4 element jobs. I hate to admit it, but, to my eyes and to my astonishment, the T6 Naglers and Pentax XL's are much better on axis eyepieces than I thought possible considering the number of elements and the field of view. Of course, another way of looking at this is that there is still substantial room for improvement in the simpler designs.