Naglers & Plossls vs "Planetary Eyepieces"

Sirs,

I have always enjoyed the views I get in my TV eyepieces. But recently, I have been wondering if there is anything to the idea of "planetary eyepieces". Most reviews of these, do support them as being better on the planets/moon. Without getting into a big debate on this, I was wondering what your thoughts were on "planetary eyepieces" and if I do try some, which ones I should try. I was thinking of University Optics H.D. Abbe Orthos, TMB Super Monos, or (maybe!$) Zeiss Abbe IIs. They would be used in a quality f4.3 Dob and APO refractor.

Thanks for your thoughts in advance, Ralph

Ralph Skogen said:

Sirs,

I have always enjoyed the views I get in my TV eyepieces. But recently, I have been wondering if there is anything to the idea of "planetary eyepieces". Most reviews of these, do support them as being better on the planets/moon. Without getting into a big debate on this, I was wondering what your thoughts were on "planetary eyepieces" and if I do try some, which ones I should try. I was thinking of University Optics H.D. Abbe Orthos, TMB Super Monos, or (maybe!$) Zeiss Abbe IIs. They would be used in a quality f4.3 Dob and APO refractor.

Thanks for your thoughts in advance, Ralph

My short answer is to quote Alan french, "Differences are subtle."

I do a lot of my observing with Nagler type 6 eyepieces, and they are very good planetary eyepieces. I do own a set of Super Monos and they are better on planets and the moon than anything I have ever used (also on the ring nebula). I've never used a Zeiss Abbe. It's there, it's real, and it's subtle. But, it's not like getting a period, even a special moment, of really improved seeing conditions where suddenly Mars comes to life, or Enke's division makes a cameo appearance. I've actually had more of those with the Naglers just because they spend more time in the scope.

That's my personal experience. I do have the planetaries, and I haven't tried to sell them, but I'm not so sure that I would buy them again. (I'd probably try a Siebert modified ortho if doing it again.)

No doubt, others will have their own opinions.

Well, I've had far more disappointment than pleasure as a net result of my experimentation with the simpler, so-called "planetary" designs, but the disappointment was not for lack of performance but for lack of what I would consider anything significant enough to compensate me for the trouble of the whole affair. In short, it never made me happy, and you can be quite certain that it won't compensate for bad seeing, which is the usual performance bottleneck I personally see.

But that is my personal conclusion after years of playing with these things. It is by no means the usual outcome. You simply have to try some affordable things and decide whether you're on the right track. If I were you, I'd buy an UO HD ortho and maybe a TMB SM in a favorite planetary focal length and decide for myself. I'm assuming the ZAOII's will be too hard to come by unless you grab an entire set, and if you have to mention money at all, I'd hesitate to make that kind of investment before I knew it was definitely the direction I wanted to go.

I was thinking of University Optics H.D. Abbe Orthos, TMB Super Monos, or (maybe!$) Zeiss Abbe IIs. They would be used in a quality f4.3 Dob and APO refractor.

Thanks for your thoughts in advance, Ralph

Ralph: Others have addressed the images themselves, myself, I think there are some other issues to address that are important to consider, particular when considering the DOB.

The Focal Length of your Dobsonian is about 16000mm, I imagine the APO is shorter. This means that your planetary eyepieces will generally need to have rather short focal lengths, definitely under 10mm and some definitely under 5mm. These short focal lengths combined with a simple eyepiece design almost always mean short eye relief which in turn means a rather uncomfortable viewing experience.

Furthermore, for me, short eye relief means my eyelashes will quickly contaminate the eye lens with eyelash oil, thus negating any slight advantage in contrast the eyepiece might have enjoyed. Further I find eyepieces with small eye lenses difficult to clean, they are just all edge...

So from a practical point of view, eyepieces such as the Naglers with somewhat more eye relief (lots more if one is only viewing in the center) and large eye lenses are more comfortable and easier to keep clean. In my view both these factors are important in getting the good planetary views.

With your F/4.3 Newtonian/DOB, it is important to consider that most of these designs do not take kindly to such fast telescopes, not only are you fighting coma, correctable with a Paracorr, but you will be using eyepieces that are sharp but not off-axis. If your DOB is driven, this is not so important but if you are hand tracking, then I find the combination of a Paracorr and eyepieces like Naglers that are sharp off-axis yield the best planetary views. The sweet spot is just a whole lot bigger...

That's my two cents...

Jon

I think there is definitely something to them As a community we see DSO purists gravitate to particular wide fields, and planetary purists gravitate to particular simpler designs. So people are seeing differences.

I think you have to ask yourself how much of this type of observing you do and if it is the kind of observing that gives you the most enjoyment. If it is, then definitely worth experimenting and training your eye to see the differences these specialized EPs can readily deliver. But be warned, they are not as comfortable as what you might be used to from the T6 line. I myself like comfort as much as the next person, but I also like optimum performance as well. I solved the problem by having both, comfortable things like Radians, then the specialized planetaries for when all that matters is maximum detail.

I'd say go inexpensive and get some UO HDs or BGOs, then experiment and compare for several months and train yourself by observing the differences. Once you know what they are, they stick out obviously when observing, especially when using larger aperture scopes. After that if you like what you see, you can then go to the more expensive varieties that you mentioned and IME these do even better.

Anyway, good luck which ever way you go. In no case does any quality eyepiece give less then excellent results on planets. So they all cross the finish line screaming and doing a great job...just depends if you want to cross the line first or not

The planetary EPs that are for sale for $54 from Teton are just fine. Longer eye relief than a plossl or an ortho, so to me more useful and comfortable.
I have a complete set of them and at $60, they are a good deal.

My Nags always did a fine job on the planets. I think maybe the Radians are a hair better, i have used over 1000x with the Radians on 9+ seeing nites and they work great.

Chas

I've used just about every eyepiece out there on the planets and other objects. Yes sometimes differences are subtle and other times when seeing is good a certain design pulls way ahead of all others. I always considered my SPL's to be the best eyepieces pulling way in front of a Nagler, Brandon and plossl. I use a Baader V binoviewer on my AP 160 with with the eyepieces being compared in the bino so I can switch back and forth quickly. The SPL's beat everything hands down until I was loaned a set of ZAO's at the WSP a few years back. At first the sharpness and contrast was subtle but it soon became apparent the ZAO's were slightly sharper and much more contrasty. In average seeing I doubt you would be able to tell the difference between a ortho and plossl but when seeing improves you may want a good ocular in your eyepiece case. I've never seen a eyepiece that scatters so little light and is sharp and contrasty as a SPL or ZAO. My advise is to figure out the focal length you want and wait for one of these to come on the used market. If you can't wait I find a TeleVue 3mm to 6mm zoom surprisingly good on the planets so long as you don't mind the warm color. This eyepiece performs very well when the seeing is average and let's face it that's most nights. The eyepiece is also available from most vendors new but I almost never see it used on Astomart the last one was offered in August 08'. What does that tell you? I like that I can zoom from focal length to focal length depending on the seeing conditions. I rarely use the 3mm setting but find myself at 5mm most nights. This eyepiece rarely is considered by most as a serious planetary eyepiece but I find the performance to be very good. Hope this helps, Martin

I have used lots of EPs including Clave, Petax, Televue, Zeiss and many others.
With the expensive ($900) Zeiss orthos for instance, yes the color is more neutral and perhaps slightly more sharp than a TMB Planetary EP ($60) under ideal conditions.

So, if you have a lot of money to spend or conditions that will allow slight improvements to be readily seen, then the expensive EPs are great, if you can afford the price.

But if you are on a budget, the $60 EP will do nicely and you can have a whole set for the cost of less than one premium planetary EP.

The differences between the best and just good EPs is not huge. It is like the difference between a winning dragster, it wins by a fraction of a second. Certainly a win, but by such a slight margin it is less than a blink of the eye.

This is the thing about optics. The differences are usually not so large that it is totally obvious, but rather subtle and even sometime difficult to describe.

I have found that with time I have come to have strong preferences and reactions to eyepieces. This is in part due to optical performance, but also due to ergonomics and feel. Some of the dob users here have noted their preference for better off-axis performance in an eyepiece because they don't have tracking and need to let go of the scope to let it hold still for the "best view." But the object drifts. So someone with that consideration may actually "see more" out of a wide field eyepiece on planets than with a specialized planetary eyepiece. The small fov of the planetary eyepiece would mean that a higher % of time must be spent repositioning the scope, and that higher % of time means that a higher % of the best moments of seeing are lost, and so, any theoretical gain from the specialized eyepiece will be reduced by considerations that have nothing to do with eyepiece design, except of course in the sense of fov as it impacts one's observing capabilities.

If you have tracking you might come to different conclusions. Ergonomics also matters even if you do have tracking. If an eyepiece is exerting a subtle level of discomfort you will likely tire of using it and again miss the moments of good seeing because you spend less time chasing that last detail.

It seems to me more rational to invest in wide field eyepieces first, starting at longer fls and then gradually narrowing down, and save the simple designs for the very last things on one's acquisition list. Here's why:

1. On any given night, the sky is the biggest optical enemy. The differences between widefield eyepieces and specialized "small and simple" won't show "more often than not."
2. There aren't that many planets to play with, but there are many dsos. With the possible exception of splitting doubles, wide gets you more.
3. Not only are there not that many planets to play with, but six months a year they are not optimally positioned; and they take hemispheric jaunts which further compromise their performance, as Jupiter these past two years. And of course they are typically up only part of the night. Saturn has the same issues AND the effing rings turn edge on.
4. Then there's Mars which gets reallllll tiny when not in opposition.

So I'm not saying don't get "planetary glass". I'm just saying widefields and the aperture you prefer should come first. As for the rest: I'm deep into XWs, and if XWs did not exist, I would have XLs, and indeed had XLs until I got my XWs. I like wide fields but I'm simply happiest with an XW due to my sense of sharpness, clarity, comfort, etc. This is very difficult to describe. I flit from telescope to telescope like anyone else at a star party but there is this feeling of "ahhhhh" when I chance to alight on a Pentax. Like everyone else 90% of what I encounter among those springing for "upper tier" glass is Televue and I do fine with it, but the direction of my personal eyepiece box is moving away from TV.

I have recently acquired some glass which I haven't had a chance to use yet, but suffice it to say, I followed my own advice.

regards
Greg N