Planetary Eyepiece Comparison

By Daniel Mounsey

INTRODUCTION:

I’ll just get it out in the open now. I have been asked if my views have changed since the first review “Planetary Eyepieces”, so that’s what this review is for. Instead, I’m going to go into a bit more discussion regarding each eyepiece. Some of these observations were conducted with Dee who you all know on Cloudy Nights so I’d also like to thank her. Hopefully she learned some things from all this but most of all, it was nice to see her make some of her first comparisons of eyepieces ever.
Here’s what I look for in an eyepiece. I’m not as concerned about other issues as much as I am regarding “on-axis” image quality. Some observers go through a tedious investigation of field of view, pincushion and edge sharpness but I don’t concern myself as much about these issues except for certain circumstances while using faster optical systems or scopes without RA tracking.

One observer I admire regarding eyepiece comparisons is Thomas Back of TMB optical. If you examine the way he reviews eyepieces, you’ll see that he just says it like he sees it. He doesn’t go into technical detail about the eyepieces, he just looks through them and judges them with absolute simplicity and that’s how I love to hear things. He’s also an experienced purist who knows good optics from bad good optics whether it’s eyepieces or scopes. I admit, there are circumstances where eye relief is an important issue to consider and sometimes it needs to be discussed.

This does not mean technical details are not important, in fact they are very important in some cases because eyepieces behave differently to various observers and various scopes. Mike Hosea and Don Pensack have been very helpful in helping others in this area.
I’ve kept a diary over the years while making comparisons of eyepieces, some recent, some old. I used various instruments from fast Newtonians down to F-4.3. I also made comparisons using small and large apochromats. Of all the systems, the apos are the most simple to deal with. All you have to do is set them up and they work and most of all they are practically immune from thermal currents. The best views of planets I’ve ever seen though have come from high quality Newtonians of careful design but refractors are simple.

ISSUES REGARDING EYEPIECE QUALITY

Contrast is usually the underlining issue, however I’ve actually seen some instances where certain eyepieces and barlows in particular just don’t appear to look as crisp. Mike Hosea’s examples of Jupiter here are example of low contrast and high contrast along with sharpness and softness.

Here’s how I define CONTRAST – A striking dissimilarity in color or pigmentation.

Here’s how I define SHARPNESS – Abrupt, clean cut, crisp, well defined, hard.

BARLOWS

There’s been a lot of questions regarding which barlow to buy. As far as I’m concerned and based on the tests I conducted, the Televue 2x and 3x barlow produce the sharpest and highest contrast available. The Vernonscope Dakin barlow is also fantastic and compares to the Televue. Another fantastic barlow is AP’s Barcon. Many observers ask if the Powermate is better. Regardless of how many tests I conduct, the on-axis view of the standard 2x Televue is superior. It’s crisper and has noticeably higher contrast. Some observers are content with their Powermates because they flatten fields and reduce vignetting which are two issues which have no advantage to on-axis views. Crispness and clarity are my biggest concerns. Also, if you are concerned about barlow degrading the image, the differences are not that dramatic. You really need ideal seeing conditions before it becomes noticeable and even then it’s extremely close. I use barlows all the time and own about four different configurations of it which I had made for me.

BINOVIEWERS

If you can ever afford a bino, two eyes are easily better than one and there’s just no comparison. My favorites in order of optical quality are the Baader, then the Televue and finally the Denk.

EYEPIECES DISCUSSED

I’ve left out some eyepieces because there’s quite a few, so if I didn’t cover one you like, then just ask me and I’ll let you know if I’ve tested it. It would take a while to cover them all.

UNIVERSITY OPTICS ORTHOS – I love these eyepieces. Even though they are over shadowed by other contenders, I’ve seen instances in certain scopes where I actually like them better than many others. We did the crucial tests with the 4mm and 5 mm. Honestly, unless the seeing conditions and the scope are good, you may be pressed to see a difference but once you know what to look for, it starts to become noticeable against high end eyepieces like the Monos. There was an instance where I tested them against some TMB Monos in the TEC 200 apo and noticed it, particularly with the glow around the planets, in fact John who owns the TEC isn’t even that experienced and he noticed it pretty fast. Every time we put the Monos in, the glow was literally cut in half but remember that the TEC is a very high end scope with extreme contrast which will tax any eyepiece to its limits. Dee and I also compared my 5mm UO to her 5mm Mono in the TOA 130 and FC100. When we examined the bands of Jupiter in careful scrutiny, you could see that the picture was a bit more contrasty in the Monos. It was like an extremely subtle cloud over Jupiter in the UO’s but still it wasn’t that far behind. Interestingly the differences were more significant in the 200mm TEC and I believe this happened because of its increased aperture and oil spaced objective. Over all, I would strongly recommend the UO’s to any experienced observer and at $59 a pop, how can you go wrong?

I do have some issues with the 18mm in particular if you wish to barlow them or bino them. Inside the barrel is a beautiful knife edge field stop, but the retaining ring which holds the elements inside is improperly painted with a sort of semi-gloss enamel and light tends to get scattered inside this retaining ring. It’s really too bad that the sub-contractor who manufactures these eyepieces for UO doesn’t just make some improvements to these eyepieces. From a physical design standpoint regarding the cone tops, they are nicer than any eyepiece in this entire review. I can only assume that their low cost is because they are not fully multi coated, but what an even greater eyepiece they would be if they improved the coatings instead of going to the less comfortable HD design. The images in the UO’s appear neutral and cold and I especially love them on the Moon.

UNIVERSITY OPTICS HD – If you are wondering whether there’s a difference between these and the standard UO’s, there is. Each eyepiece we tested brought the light scatter down a small but noticeable percentage less than the standard UO’s. It got to the point where we could take them in and out and see this difference in background contrast. I also love the 18mm’s for binowing in particular, they are very well baffled. I did get the 5mm HD which disappointed me. The contrast was horrible and I sent it back. I was a bit skeptical about it because the FOV was also wider and it looked like a knock off eyepiece. Over all the contrast in the HD’s is a notch up from the standards. Images are cold and are quite similar to what you see in the Tak LE’s. I would recommend these eyepiece to any observer.

TAKAHASHI LE’s – I’ve tested all the LE’s and they are very impressive. While viewing the Moon, the field stops are super clean cut with cold image quality. I ran some very careful tests in the 8″ TEC against the Monos. In comparison, the low contrast planetary color on Saturn’s disc was practically identical. The only difference was the light scatter. There was just a little bit more scatter and less light through-put in the LE’s. The model tested was the 7.5mm and 8mm Mono. Either way, I highly recommend the LE’s, many purists like them. The 24’s and 18’s are great for binoviewing. A great lunar eyepiece. They are a cut above the UO’s in contrast for planets.

ORION ULTRASCOPIC/PARKS GOLD SERIES – The reason these two are together is because they are the same eyepiece with different labels. I tested them all very carefully. I know this review is about high magnification planetary eyepieces, but I still must comment that the 30mm and 35mm models are well designed even though they lack a bit in contrast when compared to others of similar focal length. The 3.8mm, 5mm, 7.5mm and 10mm are not as impressive to me. When comparing them to higher end optics, I noticed they appear to be lacking in contrast. There’s noticeably brighter glow around planets, granted other observers on cloudy nights are content with them. The images are cold but I prefer the HD’s. I’ve also compared the 15’s and 20’s in the bino against the Tak LE’s, and the Taks are definitely a cut above in contrast. I also mentioned that I was blown away when Jorge and I tested the 15 Parks against a pair of Televue 16mm type 5 Naglers in the Baader bino and 8″ TMB and both Jorge and I noticed better contrast in the 16’s. We were amazed. It was like a glow that went to almost lights out when the type 5’s went in. In the first review, we didn’t have the 16’s and most of my comments regarding Naglers had to do with the type 2 models as well as the original Nagler 4.8 and 7mm and other various wide fields of different brands and design. All in all, I’d rate the Ultrascopics and Parks as good but not great planetary eyepieces based on the observations we’ve conducted. My observing buddy June owns a set of the 10’s and 35’s but he doesn’t care for the 10’s all that much because of the issues regarding contrast once again. We also conducted a comparison of the 35 Ultrascopics against a pair of 40mm Televue plossls while viewing H-alpha. Both June and John Risti were present. We were stunned to see considerably finer contrast in the TV’s because we expected the surface contrast and background contrast to be better in the Ultrascopics because of the added magnification and what we got was just the opposite. The Ultrascopics revealed a scattered glow of red from the Sun while the TV’s were etched in darkness. All of us were amazed and it was very obvious. I’ll leave it to you guys.

NAGLER T6 – You will notice that Naglers took a back seat in my first review. Well not anymore. The T6 is a noticeable improvement over the earlier design in every way. Light scatter is extremely minimal in fact both Dee and I were surprised to see that there was even less light scatter in the 5mm and 7mm T6 than either the UO or UO HD. The T6’s are wonderful for planets and proved so in my friend’s 14.5″ Starmaster. Images are a subtle warmth compared to others. Naglers are well known for their correction in fast optical systems and considering the fact that they’ve been improved so greatly, I would highly recommend them for any scope, which is contrary to my first review.

PENTAX XW – Now these series of eyepieces are a killer. Never in all my years have I seen a wide field perform like one of these. I carefully tested the 3.5mm, 5mm and 7mm against the other eyepieces in this review mentioned above and it cleaned them all out, including the reputable Tak LE 5mm in every manner. The XW represents the pinnacle of the wide field planetary eyepiece arena and was also a cut above the T6 in both surface contrast and light scatter upon careful examination both in the 14.5″ Starmaster and FS102. Image clarity is completely neutral with no visible light scattering or internal reflections which plague lesser eyepieces. Pentax puts out great eyepieces. Their .965 ortho are John Pons favorite planetary eyepiece of all time and he owns just about everything that’s great. Pons is a grand master with 53 years under his belt and uses the most exotic planetary scopes.

TELEVUE 3-6 ZOOM – Around the time this eyepiece was first introduced, I tested it in an 4″ AP Traveler at Charlton Flats. I set it to 4mm and compared it to a 4mm Zeiss Abbe ortho. After changing the eyepieces in an out over and over, I couldn’t help but notice that the Zoom was definitely softer and I concluded that it was like most other zooms. I even examined it carefully to be sure. When I seriously began to question this particular zoom was when I tested another model about two years later. In daylight testing I set it to 5mm and compared it to a Parks 5mm Gold Series plossl using an FS102 early in the morning and I had two other observers with me at the time. I was literally shocked at the differences. The Parks had a faint cloudy cast while the Zoom was etched in perfect contrast and sharpness. This was when I started questioning my first impressions. After this, I still never attempted to test it in the evening until I saw Dee’s. Dee and I used the Zoom set at 5mm along with a 5mm Mono and a 5mm ortho on two different occasions. The second occasion was Jupiter. In terms of the actual planetary color pigmentation on Jupiter and as shocking as this may sound to some, I liked the Zoom more than the Mono. It was just a bit warmer but there was still a bit more back ground contrast in the Mono. The UO came in 3rd place but understand that I’m only referring to the colors on Jupiter. Even Dee noticed it and agreed regarding the colors on Jupiter. After the first time I tested Dee’s I was lucky enough to acquire the original unit from the original owner and sure enough after careful testing against another demo unit I acquired from work, the old one was not the same. I would have to say that thanks to Dee, my thoughts regarding this eyepiece have changed for the better. There’s also a nice knife edge baffle at the end of the barrel. Great eyepiece, which is contrary to my original impressions. Sorry Al. I actually discussed it with him at RTMC.

EDMUND RKE – If there was ever an eyepiece that really surprised me, it was the RKE. Too bad they were not so respected over the years since they’ve been around as long as most veteran observers can even remember. Some of the finest planetary images I’ve ever seen have been through the RKE’s and they rank as one of my favorite planetary series of all time. Sadly, right around the time the original planetary eyepiece review, Edmund was going through some transitions and at least during some of my experiences and others, the quality just didn’t seem the same in some of them but not all were like this. Carlos Hernandez, who is one of the most highly skilled planetary observers in the world became curious about them after the planetary eyepiece review was posted. After receiving them, we had communicated with each other regarding the quality. I recall him mentioning that the field stops in the barrels had some burrs around them. This doesn’t affect optical quality but it does create doubt regarding quality control. In some of the later models I noticed this as well. Another issue was when my observing buddy John Risti acquired a set of the 28’s for his bino and sadly in one of them had polishing streaks in the actual glass as if it hadn’t been fully polished. One clue I noticed in some of the later models were the black barrels, which appeared to be painted instead of anodized on some units. Most of the earlier models were anodized. I cannot state that this necessarily determines the good ones from the not so good ones, but it helps. Some observers absolutely love them, myself included, but some don’t. Never the less, the images are cold and they’re awesome for the Moon, Saturn and Mars. Unfortunately the 8mm has a reversed volcano top, which makes it a bit less inviting to look through, but if you can get a set of good ones, they will not disappoint you. I recall a number of occasions while comparing them to others at Charlton and seeing them outperform some of the best eyepieces in this review in the contrast department and they can be very crisp. Strongly recommended, especially if you can find some earlier models and the 15mm 21.5mm and 28mm are wonderful in a bino. You’ll probably either like’m or dislike’m.

PENTAX XO – When Pentax first introduced this eyepiece I have to admit I was less than excited. How wrong I was! It is so sad that Pentax does not have this eyepiece in anything other than a 2.5mm and a 5mm. If you’ve ever wondered what they’re like, I’m here to tell you that they will compete with any planetary eyepiece in the world today. The contrast is absolutely stunning, in fact the only difference I could possibly detect between it and the TMB super mono was light through-put and even that was barely noticeable. Other than this, the light scatter and contrast was nothing short of sensational, making it one of the finest planetary eyepieces of all time IMO. Images clarity is completely neutral and crystal clear. Expensive but about as good as it gets. Strongly recommended. Images cold

TELVUE RADIAN – Sadly, I’ve just not been able to get into this eyepiece despite the fact that I’ve tested numerous models. Perhaps it’s the internal lens design. What I noticed in two different 12mm units were internal reflections. This also occurred while testing a 5mm unit as well. This is not to say the Radians are bad. Some observers have had wonderful experiences with them on planets however for me, I just don’t get that impression. I’ll leave it to you.

CLAVE OF PARIS – I’ve never seen an eyepiece as warm as these, in fact they’re warmer than any Televue eyepiece I’ve ever seen regardless of the model. They exhibit a unique coffee tone which gives Jupiter a gorgeous richness in the bands. Sadly they are rare and hard to find but will sell on the used market for about $200 to $250 used. If you’re lucky enough to find one you like, don’t hesitate, they won’t disappoint. Very similar to Televue’s plossl however I still like the crispness of the TV’s. I don’t like it as much on the Moon, Saturn or Mars but Jupiter, it’s wonderful. Pons has every one, all the way up to the 2″ 70mm which many of you have probably never even heard of. Images extremely warm.

BRANDON – When I first reviewed this eyepiece I was hard on it because I was hoping to get a bit more warmth out of the image for Jupiter. What I’m about to share with you may sound surprising but this occurred at Charlton Flats where we conduct planetary observations. My friend Jorge and I were observing Saturn with his 8″ TMB and his then new Baader binoviewer. We tested various eyepieces that night. The 12.5mm UO’s, 15mm Parks Gold Series, 16mm Nagler T5’s and a set of 16mm Brandons. To my amazement and Jorge’s, we were actually shocked to see that the Nagler T5 16’s clearly beat out both the UO and Parks GS. We could easily see less light scatter in the 16mm T5 Nagler’s, then when we popped in the Brandons it was all over. The image was completely etched in tack sharp contrast and clearly out performed these other sets of eyepieces. Like I said before, I was hard on the Brandon’s, but they are highly regarded eyepieces. Pons loaned me two complete sets in brass for testing. Images are completely white and neutral and are probably the finest eyepieces for solar wedges. If you’ve never seen sun spots in a solar wedge, trust me, you don’t know what you’re missing. Glass and Mylar filters are not even close in comparison to a solar white light wedge! The Brandons are highly recommended and are stunning on the Moon.

TMB MONO VS. TV PLOSSL – The TMB’s seem to have become the standard by which others are judged. Look at me, I used them to judge other eyepieces as well. Since many observers feel this way, I’m here to share my own input. My main instrument of choice was the TEC 200 despite the fact that I’ve tested all these eyepieces in other apochromats. The TEC exhibits some slight under correction but this in no way has hindered the image. Seeing slight differences in the star test is completely normal and I love the TEC’s contrast since the elements are oil spaced. I’ve tested various focal lengths in the Mono series but the most interesting test of all occurred while using an 8mm TV against a 10mm Mono. Now I know many of you are thinking this is a bit odd because of the difference in focal lengths but I had reasons for conducting the most crucial test this way.

Several years ago I used nothing but an FS102 for planetary observations. I used this scope for a full five years and viewed many nights with it. My observing buddy had and FS128 which he had already been using for about 8 years. My 4″ was a small scope but I learned a lot from using it. What many observers forget about while viewing planets is that as you increase magnification, you are decreasing planetary color contrast. It’s like taking a piece of pink chewing gum and stretching it out. The more you stretch it, the whiter it get because you are taking that same information and spreading it out. This same effect happens on planets as you increase magnification. In order for me to get the same color contrast as my friend was getting in his 5″ Tak, I would have to decrease my magnification, but the price I would have to pay is having to observe a smaller planetary disc.

In the TEC we used an AP Barcon at 1.7x according to AP’s stats. This would give the 10mm Mono 317x on Jupiter while the 8mm TV would propel the TEC to 396x. This is about 40x per inch for the Mono and 50x per inch for the TV plossl. These magnifications are a bit extreme under most circumstances but necessary for this comparison. I used eagle eyed June Trejano to help judge the images on this incredible night.

I observed with the Mono first at lower magnification. Jupiter’s bands revealed a gorgeous wealth of detail and I could actually discern little white ovals within the polar hoods. No Red Spot was present at this time but I could discern subtle color shadings. The browns and beige colors were accurately represented IMO.
I then popped in the TV 8mm and was dumbfounded. I didn’t say a word and allowed June to compare the two before I spoke. After watching him switch back and forth I finally said, well? The first words out of his mouth were, I like the Televue. You know what? I concluded the exact same thing.

Some purists may be surprised at my conclusion but just because an eyepiece gives you the most accurate representation of planetary colors does not mean they look their most pronounced. I took an image of Jupiter and held a B+W coffee filter over it granted I don’t like filters and asked Dee which image she liked. She noticed what I was talking about pretty fast. The TV has a slight coffee tint, but it’s just enough to give it that edge in color contrast over the Mono and what’s even more incredible is that it did it at higher magnification. Remember the chewing gum? We all see colors in different ways and some purists prefer the Monos and that’s OK, we all have opinions. My opinions are based on very careful visual tests and unlike most purists who are obsessed with white, I’m not. I like a little warmth or depth in the image. In other words a more rich and creamy appearance. I should also say that the while comparing the 8mm in both brands, the Televue gave up absolutely nothing to the Mono in background contrast or light scatter characteristics. This whole issue with me has to do with color pigmentation. The Mono does have more noticeable light through-put though.

The Televue is not without its faults. Some vignette on their own, particularly in barlows but for axial performance, it doesn’t matter. I also don’t care for them on the Moon. I do find it sad that Al Nagler doesn’t have the TV plossl produced in various 1mm focal length differences starting at 4mm but regardless, the Televue plossl represents the pinnacle of the planetary eyepiece world to me, thus making them my favorite planetary eyepieces of all time.