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Speers-Waler 10mm and the Nagler 9mm t1. Underdog Vs the Terminagler:
From left to right: Nagler 9mm T1, Tele Vue 11mm Plossl, Speers-Waler 10mm
Tom's article is given the status of a "Peer Reviewed" article as he successfully completed a peer review of his article prior to posting. The Peer Review program is a pilot project in which submitted articles are distributed to a committee of knowledgeable amateurs who assess it for content. Both the committee and author are given a private discussion forum to work out issues. If the author complies with the committees suggestions then the article is posted with the status of "Peer Reviewed". The pilot program will continue on for one more article before we decide whether to use it permanently. If we decide to use it permanently, it will always be a voluntary program and authors can still submit directly to me if they choose. (02/21/02)
Some of you may have read my previous review on the Speers-Waler 10mm. In short I stated that I felt it offered Nagler-like performance for about half the cost. Recently, I had the opportunity to pick up a new 9mm t1 at a price I just couldn't turn down. This gave me the opportunity to review both eyepieces side by side, to see how they stack up.
Before I start, I would like to make absolutely clear these results were obtained through my scopes, at my site and with me as the observer. Although that may seem obvious to many I want to be sure to state it. Eyepieces are a VERY subjective thing. All other considerations aside, I tend to prefer eyepieces that give me a "you are there" feeling, ones that tend to be immersive I 'm not much for the clinical view. In addition, I am a DSO guy who occasionally looks at the moon and planets. My site is about 100+ miles north of Detroit, in the middle of Michigan's thumb - Farm country. I live on the outskirts of a small town of 800 souls, just off the golf course. There is some light pollution over the town to the west, but not much considering. There is a factory about 3 miles to the NW, that contributes more to the skyglow than any two towns in the area combined. Fortunately, because it's a smaller concentration, this only damages a relatively small portion of the NW sky. You would swear though, that their lights are pointed straight up. Evidently the owner is not concerned about costs, efficiency or light pollution. On the whole though, my site is fairly good. Most nights give me a limiting magnitude of about 5.5. If I really need darker skies, I can drive to a nearby state game area (about 5-10 minutes) and set up on a wonderful site.
Mechanicals and Appearance
The Speers-Waler 10mm is a 5-6 inch tall 1.25 eyepiece. As you can see in the photo, its black with a huge grip ring. This is one of the tallest eyepieces I've ever seen, surpassing even my Panoptic 35 in height. Build quality is decent, but there are known problems with quality control. Several of the earlier Speers-Walers were found to have dust inside the eye lens. Mine, while clean, does have some marks on the barrel near the eye lens, and the coatings are somewhat imperfect, not nearly as smooth as I believe they should be. They are a little greener in color than the Nagler. It's also a little lighter than the 9mm Nagler, but a good deal taller. At first glance, the eye lens is much larger but upon closer inspection, I can see they are really pretty close to being the same size.
The Nagler is an imposing eyepiece. Where the Speers is tall and thin, you would have to call the 9mm somewhat squat. It has a 1.25" / 2" skirt, allowing use in either size diagonal. Build quality is excellent, coatings are even, perhaps slightly bluer in color. It's heavier than the Speers, and feels a good deal more solid. If I had to have an eyepiece to throw at a bear while out to the state game area, this would be it ( I would briefly consider throwing my Panoptic 35, but the bear had better be pretty close for that one). It would put a really good lump on his noggin. In build quality and quality control, I would have to say the Nagler wins hands down.
The Stats (calculated with a Pronto)
|Nagler 9mm t1*||Speers-Waler 10mm|
|TFOV||1deg 33 sec||1 deg 26 sec|
|weight||410 grams||320 grams|
* Discontinued but dealers still have new in stock as of this writing (02/2002)
**I have some issue with these specs Because of results during testing, I can easily tell that there is some difference between published specifications and what the product actually delivers Read on.
These observations were done through an f6.8 pronto and a NexStar 5, at night. A number of targets were observed, including but not limited to Jupiter, Saturn, the Moon, the m42 complex , Alnilam, Alnitak and Sirius.
Both eyepieces gave wonderfully sharp flat FOV's, with bright images and pinpoint stars nearly all the way out to the edge. The entire FOV of the Speers is easier to take in than the Nagler. On the flip side, its not as immersive. You get the feeling of looking out a picture window rather than the "spacewalk" feeling you get with the Naglers. As stated earlier, I have some issues with the manufacturer stated specifications. Amazingly, the Speers has a wider true field of view than the Nagler. The magnification the Speers provided was also less than expected .I would guess that the AFOV of the Speers is probably closer to 75 deg, and/or the actual FL is something OVER 10. This is assuming the Nagler is actually 9mm, with an AFOV of 82 deg. Of course if the Nagler is not exactly as stated, then all bets are off.
The 9mm Nagler
Contrast was noticeably better in the Nagler. A few stars were visible through direct vision that were only intermittently visible with averted vision in the Speers. There was some lateral color in each eyepiece. Most of the color was actually contributed by the Pronto itself, although it was evident that the Speers had a little tiny bit more. Upon examining targets with the N5/Nagler combination, I could see color on Sirius and Jupiter, but no color on Rigel or Saturn, so not all of the color was contributed by the Pronto. I was very surprised by this result, so I posted a question to the SCT usergroup on yahoo, and discovered something that I had never heard of before - differential refraction effects. As I came to understand, because of differential refraction effects, if the scope is not cooled off to outdoor temperatures or the object being observed was close to the horizon, you may see effects such as different color limbs. I had assumed that I since I stored my scope in my unheated garage, and the net temperature difference was around 10f, I would not have to worry about cool down time. Evidently I was wrong. I must say though, that I saw none of the other signs of a scope that had not cooled enough. Given the fact that Naglers are supposed to be very well color corrected, I must now wonder if the color I was seeing was due to differential refraction effects.
In any case neither eyepiece had what I consider to be an objectionable amount of color. There was a tiny bit of pincushion distortion, but nowhere near the amount found in the larger Panoptics. It showed a nice flat field with stars that were pinpoints all the way out to the edge. To find the edge in the 9mm, I really had to bury my head in the eyepiece and look around. I estimate that only about 70% - 80% of the field was actually normally visible. This contributed in large part to the immersive feeling inherent in the Naglers. You really get the feeling that you are there and are trying to peak around the corner to see more detail. The kidney bean effect was worse in the Nagler. This was mainly noticeable when moving your head around to take in different parts of the view. Star colors were more noticeable, and perhaps a touch whiter.
When it came time to pump up the power, an Ultima Deluxe Barlow was called upon to do duty. While the specs state this barlow provides a 2x increase in magnification, various users have actually found it to be more in line with 2.4x, and it seems to vary slightly with different eyepieces. This aside it is an excellent Barlow and I was anxious to see how it worked with both eyepieces. The Nagler barlowed amazingly well. The kidney bean effect was actually reduced and eye relief seemed to increase by a small amount. It was certainly much easier to use than my 4.8mm Nagler. About the only side effect I noticed was when viewing the moon at certain angles there was a dull red ring lining the very outside of the FOV. This was not objectionable, and if I hadn't been looking for things like this I probably would not have noticed it. There was less glare and less internal reflections in the Nagler .While there was an edge distortion on the Nagler (Jupiter was stretched into an ellipse), overall it was not objectionable. While the Nagler was not parfocal with my other t1's, it is a heck of a lot closer than the Speers.
Although contrast was better in the Nagler, images were actually brighter in the Speers. It really seemed like the two eyepieces were much farther apart in focal length than their specs would indicate. If you dropped the focal length of the Speers back to 10.5 or 11mm, and increased the AFOV by a couple of degrees that would account for much of the difference. As I stated before, the TFOV was actually slightly larger with the Speers-Waler - not by much, but it was supposed to be smaller according to the manufacturers specs and my calculations. The Speers was easier to view through - you could easily see the field stop and take in the entire FOV all at one time. What you prefer depends on your preferences, but I found I prefer the immersiveness of the Nagler. I found the Speers to be more of a porthole into space. I have a feeling that part (most?) of the "spacewalk" feeling associated with the Naglers has to do with how much of the walls of the eyepiece you can see along with the field stop.
Where the Nagler had pincushion distortion, the Speers had a very very slight amount of barrel distortion. The field is very flat, not quite as flat as in the Nagler, but there is only a very very small section on the extreme edge that is affected. I found that the Speers was definitely more susceptible to internal reflections, including ones from the eye lens. Upon viewing in certain directions, I had to shield the eye lens from a light to get rid of a reflection in the eyepiece. There was an interesting spectrum (rainbow) effect in the moons glare - it wasn't too distracting though, and appeared quite infrequently, when the moon was actually outside the FOV, but very close to it. The eye relief on the Speers was noticeably better, making the it a little more comfortable to use. The Speers did not barlow nearly as well as the Nagler did. When barlowed on the moon, I noticed a VERY bright blue ring surrounding the outside edge of the FOV. While distracting, I do have to state that it was a very pretty blue :} In addition, the kidney bean became terrible when the Speers was barlowed. Although I've owned this eyepiece for a couple of months, this was the first time I have actually used it in conjunction with a barlow.
Ergonomics and disadvantages
There are a few ergonomic disadvantages to the Speers. It's a very odd form factor and can be difficult to store in the eyepiece case. It won't fit into my Pronto bag, and so tends to get left behind when I am traveling. It looks weird when sticking out of the focuser, and using it with a barlow makes it stick out even more. It won't fit into a standard eyepiece case as it is too tall. You need to have a lot of intravel in your focuser, and reportedly there are several scopes that it just wont come to focus with. I had to acquire a low profile 1.25 adapter in order to get it to focus.
On the flip side, I found I REALLY want to take the 9mm Nagler with my Pronto, but I will be forced into a decision about which two inch eyepiece I want to leave behind - the 35 Pan, or the 22 Pan. There have been issues with the 1.25" / 2" skirt on the 22 Pan. It tends not to work very well with some 1.25 diagonals (I was never happy with how my 22 pan fit into my Lumicon diagonal - it made me so nervous that I eventually got rid of the Lumicon 1.25" and just went to all 2" diagonals - I did find this skirt to work well in a 1.25" Tele Vue diagonal incidentally). I suspect it would also have problems with some 1.25" barlows, although I can tell you that it works fine with the Ultima Deluxe, and I would be very surprised if it wasn't fine in all Tele Vue barlows and Powermates as well.
Both are absolutely excellent eyepieces.
Ignoring price for a minute, lets consider both of these eyepieces. The Nagler is a slight touch better - it has slightly less glare and internal reflections, more contrast, better build quality and higher levels of quality control. It would probably be easier, at least for US citizens, to get service on Tele Vue products. Antares just doesn't have much of a presence in the states (and that is a shame). I have a sneaking suspicion that the Nagler would be better on faster scopes, but I can't confirm that at this time. Can anyone out there let me know? I do want to emphasize that (at this focal ratio anyway) the differences are VERY VERY slight between the two. The Speers is an EXCELLENT eyepiece. Which you prefer is a toss up and depends totally on what you are looking for in an eyepiece.
Now lets factor in price. While the Nagler is the better eyepiece (although not by much), the Speers is CLEARLY the better buy - HOWEVER it can be tough to find one in stock in the States. Your best bet might be to contact a Canadian dealer - I have dealt with several and have had good results with all of them.
I was incredibly impressed with the Speers. For about half the price of the Nagler it delivers 95% of the performance. If you don't have any wide field eyepieces, look into these. They aren't that much more than a good plossl, and give you a great taste of those wide FOV's.
In the long run, is the Nagler worth the extra money? Well that all depends on your tastes, and what kind of a deal you can get on these eyepieces. The Nagler does appear to have a better resale value (if you are concerned about those things at all), and does offer a little better performance. If you don't care about the money - then yes, optically the Nagler is SLIGHTLY better.
Which would I sell if I had to? Well, if it came down to it, I would probably wind up selling the Speers. You see, I already have both, and I have this illness - I appear to be collecting Tele Vue eyepieces.
NOTE: Shortly after this review went to cloudy nights, I did actually sell the Speers.
Tom is a confirmed equipment junkie who suffers from a rare form of lycanthropy - every full moon (or cloudy night) he becomes very active on Astromart. His wife keeps reminding him that trying to trade his child in on an AP or Obsession is usually considered to be against the law.