Theron Mag82, Celestron F-ED 80 and Zen Ray ED2 spotting scope comparion

I am genuinely excited to be able to write this comparative review for you folks. I had been out of the optiholics anonymous club for well over a year. Truth be told I have not had as much time as I would liked lately to get back into my hobby as much I once was. The kids’ baseball and building a new home take up a great deal of my personal time.

Nevertheless I was really enthused when I had the opportunity to compare three, very amazing spotting scopes. I had reviewed the Celestron Regal 80 F-ED a couple of years ago when it first debuted. At that time I considered it to be the best value of any spotting scope under $1000. I still do. The optical performance on it is only bettered by the true “Alpha” level scopes such as the Zeiss Diascope, Kowa Prominar, Nikon Fieldscope, etc… It was this scope that I chose to use as a benchmark when reviewing two relative newcomers to the spotting scope market…the Theron Optics Mag82 and the Zen Ray ED 2 80 mm class spotters.

These spotters have been reviewed before by other more qualified members of this forum. Links to these two threads, along with my previous Celestron review threads can be found here……

Henry Link’s Zen Ray review

Steve C’s Zen Ray, Theron, Kowa comparison

My Theron (Mag 82 and Saker), Celestron comparison

My Celestron Regal 65 and 80 F-ED thread….elestron+regal

Some of the material I am going to hit on is a repeat of what has already been stated. I cannot think of a way around that. Some of it will not be as I will try to share my opinion, perspective and preferences as part of the review. Let me start off by saying that I would love to own any and all of these scopes. I do not consider one to be exceptionally better than the other two. If pressed I would have to rate both the Theron and the Zen Ray as slightly better optically than the Celestron overall but for twice the price they should be. So, without further ado…….

Physical Attributes:

The Celestron Regal 80 is the longest and heaviest of the three scopes. It weighs in at 72 ounces and measures 18.5 inches in length with the eyepiece attached. The Theron Mag has an advertised weight of 62 ounces (without eyepiece) and measures 15.5 inches in length with the eyepiece attached. The Zen Ray ED2 has an advertised weight of 64 ounces with eyepiece and measures in at 15.3 inches length. All are physically large 80 mm class spotters. The Zen Ray has the best balance out of the three with both the Theron and the Celestron exhibiting more of a front-heavy feel to them.

The Celestron and Zen Ray both utilize a dual speed, conventional focusing knob while the Theron uses a helical focuser similar to that of the Swarovski and Nikon models. In practice I found the fine focus on both the Celestron and the Zen Ray slightly easier to use to obtain the finest detail in the quickest manner. I was able to attain the same level of detail with the helical focuser of the Theron but it too some time to be accustomed to. I would not rate one design higher than the other in terms of convenience or functionality. My past experiences were with standard focusing knobs so I had a preference to that style initially. After extended use that preference disappeared.

Focusing speed is also different for each of them (assuming we are referring to the course focusing speed only.) The Theron is the fastest by a fair margin. It takes approximately ¾ of a turn of the helical ring to go from one focus stop to the other. The Zen Ray is next with just a little bit over two full turns of the focusing knob to go from one stop to the other. The Celestron is much slower in requiring 13 turns to go from one end to the other. This is one of those areas that can down to largely personal preference. The Celestron can offer greater control in dialing in an object but can also be detrimental in case you need to focus on something quickly. And, of course, the opposite is also true of the Theron. It is excellent if you need to quickly focus on one particular object but requires more precise control to get perfect focus.

Externally both the Zen Ray and Theron feature a hard exterior powder coat-like finish which can easily be scratched or dinged. The Celestron has a skin of rubber armor over the scope to help prevent these issues. All three come with a “view through” case which can make this concern a moot point. All three features sliding sun-shades to reduce glare in difficult lighting conditions.

Optical Performance:

It has been my experience that everyone’s favorite topic is optical performance. Consumers want to know how the scope performs not only for the price but also in comparison to some of the best spotting scopes currently on the market (Kowa Prominar, Zeiss Diascope, Swarovski, etc…) This can often be a tough judgment call as we all tend to prefer different optical qualities in our gear. Some prefer the brightest possible image while others prefer the flattest image with excellent edge sharpness. In all but the most expensive scopes this can be a difficult product to find. I can say, with much satisfaction, that these three scopes deliver in just about every area of optical performance. There are some slight differences and some pronounced ones but I think that at least two of them (the Theron and the Zen Ray) are sure to please all but the very most critical of optical aficionado. The Celestron is not far behind optically but it does fall slightly short of the other two models in a few key areas.

All three scopes utilize some form of extra low dispersion glass in their design to aid in reducing chromatic aberration thus producing a sharper, more colorful image. The Celestron Regal uses an air-spaced doublet objective while the Zen Ray and Theron utilize air spaced triplet objectives.

To aid in the comparison I wrote up a brief comparison chart which illustrates various aspects of the scopes’ optical performance in comparison to one another. Keep in mind that all of the scopes perform well above average in their respective price ranges so the results are entirely relative to the other scopes in the comparison.

Rankings were based on the “1-first, 2-2nd, 3-3rd” system. If I felt two scopes were too close to call in one particular area then I gave them the same score. I wouldn’t put too much stock in tallying the totals because we all tend to put more emphasis in one area or another.

Celestron Regal Theron Mag 82 Zen Ray ED2(20-60x zoom)

25x zoom setting

Apparent Sharp. 2 1 2
CA control 1 2 (edge control) 1
Apparent Brightness Equal Across the Board
Edge Performance 2 3 1
Contrast 3 (close to 2) 1 2
Field of view 1 2 1

40x zoom setting

Apparent Sharpness 2 1 1
CA control 3 2 1
Apparent Brightness Equal Across the Board
Edge Performance 1 1 2
Contrast 2 1 2
Field of View 1 2 1

60x zoom setting

Apparent Sharpness 2 2 1
CA control 2 3 1
Apparent Brightness 2 2 1
Edge Performance 1 3 2
Contrast 2 3 1
Field of View 2 3 1

30x Wide Angle (30x zoom setting on Celestron)

Apparent Sharpness Equal Across the Board
CA control Equal Across the Board
Apparent Brightness 2 1 1
Edge Performance 1 1 2
Contrast 2 1(yellow cast) 2
Field of view 2 1 2

A couple issues of note….

1. I also compared the 25-50x wide angle zoom for the Zen Ray at the same time. It scored relatively identical to the 20-60x in every category with slightly better apparent sharpness at the lower magnification settings and, of course, a noticeably wider field of view at all settings.

2. The Zen Ray 20-60x zoom lost the sharp edge to the field stop at both the 25x and 40x settings. At 20x and 60x the fieldstop was again sharp. For this reason, and to a lesser extent the wider field of view, I prefer the 25-50x zoom over that of the 20-60x.

3. I did notice the barrel distortion in the Zen Ray 25-50x wide angle zoom. It was most prominent at the lower magnification setting and when panning. It was still there but much less noticeably so at the 50x setting.

4. The Theron 30x wide angle eyepiece was probably my preferred eyepiece out of any of them because the image is so wide, so flat and so sharp. Very little CA was present in the image as well. Second place would go to the Zen Ray 25-50x wide angle zoom. I was satisfied but not enthused about the Zen Ray 30x zoom. Its slightly narrower field of view (in comparison to the Theron) was noticeably to me. Plus the edge performance was not anywhere near as good as the Theron’s. If Zen Ray designed a 30x wide angle (or a 20x, 30x and 50x wide angle series) which was similar to the Theron’s then I would have a very difficult time imagining a better overall image.

5. The Theron zoom and I have developed a love/hate relationship. 😉 I love the crisp image but hate the fact that the field of view is not wider. With that thought in mind I did order a Baader Hyperion zoom to try out on the three scopes. Of course it will not attach directly to any of them but will “fit” in one form or another enough so that I can get some idea as to overall image quality. It performed most impressively with the Theron Mag82. Image quality is absolutely superb throughout the entire zoom range. Every optical characteristic was superb when these two are paired together. It has all of the edge performance of the Mag82 zoom but with a wider field of view plus more neutral color representation (the Mag82 30x wide angle has a bit of a yellow color bias). The Baader did “work” well with the other two scopes but edge performance was a bit compromised possibly because of the specific optical designs of each scope.

I did not have any issues with quality control or overall build quality in general with any of the three scopes. The focusing mechanisms, sunshades, tripod collar, eyecups, etc… all performed as expected.

I have each of these scopes for about a week…give or take a bit. Yesterday I finally had the opportunity to take two of the scopes up to the local hawk watch to see how they perform. I chose this location in particular because I find that the conditions can be particularly demanding of optical instruments. CA shows up relatively easily and apparent sharpness is crucial considering the distance that the user often utilizes the scope for.

The Theron and the Zen Ray performed admirably. As I mentioned previously, I prefer the 30x wide angle in the Theron and the 25-50x zoom in the Zen Ray. With these two eyepiece I did not feel as if I missed anything from relatively close songbirds all the way out to Turkey Vultures flying 2 miles away. I would not hesitate to use either scope in this particular application.


So, I guess the question is which scope would I want if I could have any of the three? Tough call. It would depend on a variety of issues. If money were tight then it there would be no question that it would have to be the Celestron. With a street price as low as $515 the optical performance is absolutely unbeatable. The fact that it can compete against two scopes that cost twice as much speaks to the value of this optical instrument. Its ability to use any 1.25 inch astronomical eyepiece makes it even more appealing. The downside is that is longer and heavier than either of the other two scopes plus the focusing is a bit slow in comparison.

The Theron Mag82 would certainly be a good choice because of the fast, helical focusing design and the superb optical performance of the 30x wide angle eyepiece. If a wider zoom and or some type of astro adapter could be utilized on it then I think anyone would have a hard time arguing that this is one of the better scopes on the market…at any price.

The Zen Ray continues to impress me especially with that 25-50x wide angle zoom. I cannot believe how bright, wide and sharp the image is at the 50x setting. One would expect this at 25x but to an image so similar in every regard at the 50x setting is simply astounding.

Take your picks folks. Depending on your “wants” and “needs” I don’t think you will be disappointed with any of these scopes.

3wayfront 3wayside 3wayabove


Leave a Reply