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Takahashi FSQ-106N 106MM F/5 "Quadruplet Fluorite Apochromatic Refractor"

FSQ (foreground) and Tak Sky 90 on Giro-2 Mount

The Takahashi FSQ-106 that just landed on my doorstep is an interesting entry into the most crowded section of the current refractor market - the world of four inch refractors. Let me start out with a simple description of the scope itself before launching into a lengthy digression on what I consider the place of this somewhat unique telescope in the current market.

For those of you who don't want to listen to one of Dave's typical musings on scope marketing or design, you can read the "Physical Description" section that follows this introduction, skip over the design and marketing discussion that begins with the section marked "The Four Inch Refractor Sweepstakes", and go directly to the section entitled "How Well Does It Work" to read the results of the testing. Sorry, but I just love to noodle fine optics, and the 106 represents a rather interesting offering in a crowded market:

Physical Description

The FSQ-106 is a modified Petzval design (with a discussion of how the design differs from a 'normal' Petzval appearing below) with an aperture of 106mm, and a focal ratio of f/5 (focal length at prime focus of 530mm.) With the dew shield retracted, (the "N" differs from the original version by the inclusion of a retractable rather than a fixed dew shield) the OTA is approximately - inches in length. The OTA without accessories weighs just a tad more than 13 pounds. The scope comes with a four inch focuser and a rotating camera angle adjuster - equally useful, I might add, at allowing you to adjust the angle of the diagonal and eyepiece to suit your viewing.

For those interested in photography, the FSQ provides an 88mm image circle for 35 mm, 645 or 6x7 medium format or 114mm for 4X5 cameras. With the Extender Q (an attachment designed for use with this telescope, discussed in more detail both below and in a separate review) the focal length is 850 mm or f/8. The intended finder for the 106 is the excellent 7X50, although it is not included in the price of the basic scope, and the smaller, but non-illuminated 6X30 should fit as well.

The tube can be mounted to any of the array of Takahashi EQ mounts or, if you would like (but I would not recommend, despite the factory's claim that it will work) the Teegul AltAz mount, not one of my personal favorites. The standard tube ring will also allow you to mount the 106 on the Giro-2 AltAz mount (as pictured). A set of 114 I.D. tube rings from a company such as Parallax will allow you to mount the 106 on a variety of non-Takahashi mounts with the use of the appropriate dovetail.

The 106 ships with the standard Takahashi 1.25" compression ring fitting screwed into the back of the focuser. That allows you to use an 1.25" ep straight through (the method of choice in its homeland) or with an 1.25" diagonal or prism that will slide into the back of the compression ring. (By the way, I use the Takahashi 1.25" prism diagonal. Despite all the bad press generally attributed to prism diagonals versus mirror diagonals, the prisms from Takahashi are superb performers.)

Given the design that places the rear element in close proximity to the focuser, most 2" diagonals will not work with the 106 - which (again because of its design) has some limitations on in focus travel. The distributor has modified a 2" diagonal body obtained from Lumicon that threads directly onto the back of the 106's focuser and works quite well. (That diagonal is pictured in the review I did of it last year, and can be found here) Using the Extender Q, and the Adapter Q, any standard 2" diagonal will work with the 106.

Please note that, as the manual warns, a barlow or other device that would normally fit into the back of the focuser will not work. That is a simple matter of location, as the rear element is right at the back of the focuser. Insert barlow, scratch or break rear element. (Indeed, remember to be careful not to touch the rear element when screwing or unscrewing the diagonal or extender to the rear, getting a fingerprint on the rear element is easy to do, and not a desirable addition to the optics!)

Finally, the 106 can be supplied with one of the marvelous Tenba 'armored' carry bags which, for a reasonable price, will allow the 106, and the Extender Q and the associated adapters, etc to be carried around and fit (if my measurements are correct) in most overhead compartments. (However, given the way that some airlines are dealing with these matters today, I offer no assurances on this point. Your mileage may vary )

The Four Inch Refractor Sweepstakes:

Virtually every manufacturer that has a refractor in its line of products has one in the four inch (100 to 106mm) aperture range. Most amateurs who have at least one refractor in their arsenal have a four inch scope. They are considered the 'sweet spot' for portability, ease of use, set up and transport, while representing what many feel is the 'bottom end' of the useful aperture range of a multi-purpose telescope. Given their popularity, it is hardly a surprise that so many manufacturers have concentrated on producing the best possible four inch scope to meet the demands of the market.

The traditional achromat in this size was an f/13 to f/15 instrument. When apochromats appeared on the amateur scene, they were 'faster', but usually remained in the f/8 to f/10 range of design.

But markets shift, designers have better glass choices made available to them, and faster became the watchword for refractor buyers. Was that move simply fashion? No, faster scopes could double as visual and photographic platforms, while longer focal length refractors were inherently more limited in their photographic and wide field use. Were they as good as the longer focal length apos in purely visual performance? Theory said yes, but the legions waiting for the 130 f/6 AP, the 105 f/5.9 Traveler from the same company, etc. said it all. In addition, the shorter focal ratio apos were easier to mount, could provide wide field views that the longer focal ratio apos could not, and gave nearly the same visual performance as the longer scopes as perceived by the majority of buyers. For those who traveled with their scopes, the shorter, faster apos were a God-send. It was only the true die hards that clung to their 130 f/12 Apomax and their 130 AP f/8.35s. (And before you throw that brick at me, I just re-acquired my Apomax, and did so as an act of love. More on that at another time.)

Where did that leave Takahashi? Until late 1999, Takahashi had focused its refractor product line more and more on its relatively 'conservative ' family of longer focal ratio scopes in the FS series. These excellent products were (and remain) f/8 fluorite doublets. They are primarily intended as visual instruments, with a focal reducer available for photography/CCD. (Of course, even without the focal reducer, they were superb imaging platforms, as you can see from the Jupiter images taken with the FS-152 at Todd Gross' site. Impressive!)

Of course, Takahashi knew quite well how to build a faster refractor, it had simply drifted away from those instruments. When 1999 rolled around, the once extensive line of 'fast' fluorite triplets from Takahashi had been reduced to only one - the FCT-150, an f/7 scope reputed to produce incredible visual and photographic images, and sporting a price tag nearly double that of any other 6" refractor on the current market! (Oh yes, there was and is one other FCT still available, the FCT-200, an f/10 triplet going for about TEN TIMES the already not-inconsiderable price of the FCT-150!!!) Gone were the faster triplets, which included the FCT-76, an f/6.4 and the very fast FCT-65, an f/4.9! If you wanted a Tak refractor, you ended up with a very good, but relatively long, OTA. If you wanted a Takahashi refractor, it was an f/8 doublet that you bought. (Hardly a poor second choice, by the way. My own 102, 128 and 152s were all superb instruments. Both Ed Ting and Todd Gross have also been quite pleased with the Tak f/8 doublets.)

What then would Takahashi do to meet the demand for shorter, faster refractors in the highly-competitive (and profitable) four inch field? How could they produce a fast, high performance four inch apo without bringing out what would have been a just a 'me too' scope?

A triplet? Although Tak had built them in the past, would that type of product really excite a marketplace which already saw that type of scope as the 'property' of AstroPhysics and newer companies like TMB? And, leaving the 'image' issue aside, was there a better answer out there? Takahashi thought so, and decided to build that product.

One way to build a short, fast four inch scope would be to go to a Petzval design. That design employs a 'slow' doublet lens cell at the front, but uses a second 'doublet' at the back of the tube to reduce the focal ratio. Potentially a much shorter scope overall, and potentially also one as well corrected as a triplet. However, that was not as simple a solution as it looked at first glance.

The Petzval design had been around for quite some time. Tele Vue had used that principle in its earlier 4" scopes, but retaining the tube length of the longer focal ratio f/8s. (Indeed, the newer TV-102 doublet uses the same length tube as its Petzval half-brother, the TV-101, but is a doublet just shy of f/9 in focal length.) This is done, presumably, because the resulting scope is simpler to build and keep collimated (what I was later to learn was the bugaboo of Petzval designs) than the shorter, more extreme Petzval designs - an example of which is also, coincidently, one that was once the flagship of the Tele Vue family.

The rara avis of apos is the legendary TV-140, a 140mm (5.5") f/5 Petzval. In this design, Tele Vue pushed the basic Petzval design to its maximum, resulting in a telescope which is the same size and weight of the average 4" apo, and (in fact) shorter and lighter than some. How does it perform? Read my review elsewhere at this website. Simply stated, a great deep sky scope, and hardly shabby pushing it to high magnification on lunar/planetary - albeit needing a Powermate to get this short focal length gem cranked up to its maximum potential. (And more on that later too!)

Why then isn't it still being made? While Al has never commented on the precise reason, those I have talked to that have at least some knowledge of the issue say that it was a tour de force that had to be set up just right, and was 'an absolute **** to set up and build.' Rumor has it that only 40 or so were ever built, and I question even that number, since I have never seen one nor heard from an owner of one that was numbered beyond the high 20s. And, when I had to send mine back to be cleaned and collimated, I was told it took their optician a week to get the job done to Al and/or David Nagler's satisfaction. In other words, a fast Petzval is not an easy scope to build and sell - hence the f/8 sized TV-101 and the newer, f/8+ TV-102 surviving in the Tele Vue group while Al no longer builds the TV-140 although he could probably sell a ton of them given the demand for the AP 130 f/6 and the AP 155 f/7.

What did Takahashi do at this juncture? The FSQ-106 manual explains their decision quite clearly:

Takahashi Builds a "Modified" Petzval To Go For The Gold in The Four Inch Sweepstakes:

The manual for the 106 describes the scope as a "Quadruplet Fluorite Apochromatic Refractor." On what basis does the design, according to Takahashi, set "a new standard for innovation and color correction?" The manual answers this as follows:

" The heart of the FSQ-106 is the unique modified Petzval design that employs two fluorite elements. The original Petzval design, though excellent for astrophotography, exhibited inherent problems with field curvature and astigmatism. Now Takahashi's modified Petzval design employs two widely separated rear elements to produce a flat field, high contrast image without any hint of astigmatism."

An interesting claim, but is it accurate? A quick view of other four inch Petzval designs would appear to support the claim that the FSQ-106 is indeed unique. The TV-101 is physically a much longer telescope and employs a single fluorite or super ED glass element at the rear. The new Vixen Neo-Achromats appear to use a design much more akin to the 106 than the Tele Vue Petzval, but without the two fluorite elements that the Takahashi designers employed as the 'heart' of their design. So it appears that Takahashi's claim that their design is unique in the current market may be correct.

However, how about the claims to "new standards for color correction" et al.? An f/5 design seems awfully fast for visual use, even if it may be an astrophotographer's dream. I have heard several long-standing figures on the amateur scene suggest that this scope is purely an astrograph that the US distributor is trying to push as a dual purpose scope only in the US.

Well, there are several answers to that. First, I have now heard from a fair number of users outside the United States who are happily using the 106 as a dual purpose instrument who feel that it is not limited in any manner by it fast focal ratio. And, if one looks at the manual itself, it is clear that it was indeed intended by the factory to be both a visual and photographic scope.

The manual claims the 106 is the "finest short focus photo/visual instrument available anywhere." Hmm, quite a statement. What else does the manual say? The manual states that the 106 will provide exceptionally sharp deep sky view, either for photography or in visual use. Okay, given the focal ratio and the traditionally -excellent Takahashi optics, I can buy that claim, but what about visual use. Still seems like an awfully fast focal ratio, even faster than the AP Traveler, for planetary or lunar use, a traditional application for a four inch refractor..

Takahashi's answer - again - is also found in the manual. The 106 was designed to be used in its 'standard' configuration (i.e. f/5) but still provide excellent, high contrast and sharply defined lunar/planetary images. (I will address that claim in more detail in the performance commentary below. However, the short response is that the manual is correct in this claim based on my tests.) However, Takahashi designed the 106 (and the later Sky 90) with a 'secret weapon' in mind, the Extender Q.

This small, and reasonably-priced (about the price of a 4X Powermate) device is not a barlow. To quote Takahashi, the Extender Q is a "five-element amplification device specifically designed to enhance the usefulness of the FSQ-106" and the Sky 90. (As I have also learned by using it with my FS-60C and from comments I have received from other users, with the other Tak doublets, including the FS-152, it will work just fine and boosts performance in all of the Takahashi refractors, excluding the triplets for which I have no information one way or another.) This device screws into the focuser of the 106 and turns the f/5 into an f/8.

And it DOES become and f/8, as the manual lists this ratio in its description and shows that it is an integral part of the optic system, not a generic add on such as a barlow. Indeed, the Extender Q is not a barlow as the manual emphasizes. It was not something Takahashi designed in order to 'cure' some 'deficiency' in the optics of the 106. Instead, as the manual points out (and based on some additional material I saw in a posting from a 106 owner in Hong Kong who obtained it from the company/distributor) the 106 is intended to provide the best possible visual images on planetary/lunar, but is slightly under-corrected (like most Taks and many other apos) to allow optimal use for astrophotography. This is not noticeable for most visual use but may appear in the out of focus testing that some others may delight in doing, but which I have never found the need to bother with.

However, as the manual states, and as I confirmed myself, the 106 without the Extender will still provide outstanding planetary and lunar visual images and superb contrast through the eyepiece. (The manual points out that the fast focal ratio will allow a high contrast and sharp image of the entire lunar disk at 50X. I tried it. They are right.) But for even more 'sharpness' (my phrase, not theirs) and to bypass the inherent limitations on magnification because of the short focal length, the Extender Q is designed to be used with eyepieces including the 2.8 Takahashi Hi-Ortho, producing "303X."

(Of course, as many of you who know me can anticipate, would I allow that 'limit' to stop me from seeing if these optics can be pushed to what one of my many 'fans' on SAA refer to as 'stupid and unnecessary levels of magnification? Of course not. Can it? Sure. How far? Well, let us just say REAL stupid and leave it at that.)

The Extender Q also was designed to correct the optics in the "ultra violet part of the spectrum that is used by CCD cameras" and which also "adds to the photo/visual capabilities of the FSQ-106." The information I received from the gentleman in Hong Kong, and what I have been told by other Tak users (and confirmed visually by me, as I am still feeling my way into CCD) is that while the 106 (and other Taks) are marvelous visual instruments without the Extender, the Extender removes any possible 'spurious color' or under correction issues in the Tak doublets and sharpens this already color-free Quadruplet to the nth degree. And, as noted above, it allows the use of any 2" diagonal.

Anyhow, so much for claims and now down to the pudding:

How Well Does it Work:

Unzipping the case, your first impression is of the FSQ-106N is, "wow, that is one short little scope." If Tak was shooting for the AP Traveler end of the airplane portable market, they hit that mark real well with the 'N' model and its sliding dew shied.

Then you go to take it out, and my first reaction was, 'wow, what did they do, make this from lead?" This is the first time the AP/Tak comparison reared its head in my mind, so let's deal with it here.

The AP (and I owned one before and had access to another when I was doing this review) is a lighter product. Why is the 106 this heavy? If we are talking purely visual, it is overkill or, as Ron Wodaski (the guru of the FSQ, and I mean that in the best possible sense) noted in a discussion on eGroups the other day, kind of like using a tank to go grocery shopping. (Of course, as I said in response, that tank will get you to the head of the check out line real fast.) But Ron is right, it is the dual purpose and 'best possible' approach that Takahashi set out in its manual that accounts for this extra - but not necessarily unwarranted - weight.

For purely visual use, many of the features of the 106 are not needed. However, the four inch focuser, the built-in field flattener, and the rotating camera angle adjuster all add weight to the basic package. They all enhance photography and CCD work. Add some of these features to the AP (and only some are available) and you no longer have as light a telescope as before - nor do you have one that still enjoys a price advantage over the Tak. And, when all is said and done, the 106 because of its larger focuser and design differences, is a better camera/CCD platform offering more options and more imaging options.

In other words, the extra heft (pounds and dollars as well) of the 106 versus the AP is, in car dealer parlance, comparing the 'stripper' to a fully loaded car. Do you need all the extras of the Tak? No, but they are sure nice to have. But when reduced to the bottom line issue of the inevitable comparison to the nearest competitor, on the issue of price, the Tak may even be cheaper - when these 'built in extras' are considered - than the reigning champion of the four inch, short focus, visual/photographic astrographs, the AP Traveler.

But all this is academic if the performance of the Tak wasn't at least on a par with the AP. We will go there soon, after a few quick thoughts on something that comes up in the review of any refractor or other scope such as a Dob that doesn't come with an integral mount, what do I put it on and how well does it work on that mounting?


The Tak will fit into the Teegul altaz mount and is shown in that configuration in the Tak literature. I have that mount. It will mount easily and it works - barely. The views are best using it as a low power, wide field instrument. The weight that far back on the mounting arm, coupled with the inherent limitations of the mount itself, causes the image to blur as the vibration from focusing and even normal movement with the otherwise smooth slo mo controls intrudes. The scope takes an inordinate time to dampen once these shakes begin as well. I can't recommend this mount for this scope..

If you want to mount it for quick, non-driven use, the Giro-2 Deluxe handles it just fine. (And works well at high power even with the 106 and the Sky 90 onboard at the same time.) The standard Tak tube ring will bolt directly to the Giro head, using slightly undersized bolts and washers to secure it. High power lunar/planetary is well within the capability of this mount/OTA combination, and deep sky views at lower power are a pleasure.

All of the Tak EQ mounts larger than the Sky Patrol II should handle the 106 well, as does the AP 400 with the use of tube rings purchased from Parallax. I haven't tried it on the GP-DX, but since it is lighter than some of the larger Vixens Orion sells on that mount (including the 130and 140 Petzval designs) the 106 should work well for visual and presumably for imaging purposes as well.. And, using a set of Parallax rings, it will do just fine on the Losmandy series of Eqs.

Observing Report - at long last

Using the Giro-2 as the mount for most of the testing, the first target was a very bright and very nearly full Moon. And the first impression that grabbed me and presumably anyone else using this scope for the first time was the way that this scope snaps into focus - and does so faster and with a more sharply defined and easy to recognize point of perfect focus than any other I have ever used. I presume this is a function of the focal ratio and the design, but you now right where the point of perfect focus is the first time you try it. By contrast, the AP and the 140 and even my Sky 90, the three other 'shorty' refractors in my present or former arsenal, needed a little more - and more typical - fiddling up and back to find the precise point of focus.

The 'fiddling' needed on the other scopes to locate the precise point where the image was in the best possible focus is quite normal, particularly considering what was an inherently tough target on which I was trying to get a handle on that evening. I was using various crater walls and highland areas where the glare of the full Moon offered none of the ease with which the same targets presented when highlighted by their proximity to the Terminator. You know, that gentle rocking back and forth on the focuser to get the walls, etc as sharply-defined as possible in the eyepiece. So nothing unusual about that, but what was different here was the ease with which that 'perfect focus' could be achieved with the 106.

The 106 gives you a focus snap that has to be experienced to appreciate. At first, I played around up and back with the focuser to see if I was 'really there.' I was, and I later heard from others that this was the norm for the 106. Big bonus point for me, and something that gave me a lot of pleasure. The same effect was noted on Jupiter, and on virtually every other target.

Once in focus, the contrast on the difficult target of a blazing Moon (no filters) was not typically Tak standard . It was clearly above that already very high standard. While I wanted to stay away from comparisons or 'rankings' at this point, the contrast in the 106 was simply the best I had ever seen from any Tak, from the FS-60 through and including the 152.

Shift over to Jupiter and, again, the same 'snap' into focus. The surface contrast was, again, better than any other Tak I had ever used. (Of course the larger image scale of the 5 and 6" Tak refractors give them a distinct 'leg up' in the image scale and perceived contrast and real world clarity. However, trying to factor all of this in my head, and checking my notes of my observations with my FS-128 and FS-152, the 106 still takes the laurel.) It was easy to pick out surface details in the belts, count five or more distinct belts rather than just blurry outlines, and pick out the swirls etc in one of the sharpest and most distinct impressions I had ever had of Jupiter in a four inch telescope. (Of course, even the best four inch image is not going to have the detail nor the image scale of a larger and otherwise excellent apo. The images Todd Gross took with the FS-152 at his website illustrate why we go through the hassle - and expense - of larger aperture refractors. The 106 is stunning four inch performer on Jupiter. I am not, however, going to do a side by side with my TMB 203 on Jupiter and then run out and sell the TMB. HUGE difference, as my kids would say, but the cost and 'hassle factor' difference between the big TMB and the 106 show why four inch apos are sold.) The moons were also crisply defined, both off the face of Jupiter and when I was fortunate enough to catch a transit. I would say 'tack sharp optics' but you know I hate puns.

The drop off from the edge of very bright targets was also excellent. On several occasions, when the Jovian moons were just off the edge of a very bright planetary disk, the separation was distinct and pure black, with a stray star laid out nicely in the gap. The same lack of bleed over, and the ability to pick out stars just off a full and bright lunar disk, is one of my personal tests for optics. Trying that under a variety of magnification, the 106 passed that test with ease.

Let's deal with color next. None, no spurious color at all, and sky contrast and overall sharpness impeccable. Better than any doublet I had used? Yes, and clearly better than Tak's own 102 and the various other four inch apo doublets I have tried. But, as I have confessed often, I am not overly-picky on this issue, and confine my observations purely to in focus images and the difference is subtle, not gross.

From time to time under extreme conditions (the check to see what the situation off the limb of the full Moon may be test noted above) the 102 et al will have a trace of bleed over and a trace of false color. But just a hint, albeit clearly and undeniably there in focus. Ditto on some views of Venus (yes, it always shows some color in every scope under most conditions, but how much and how 'false' is the real issue) and some other bright stars. That hint or trace is not something that ever disturbed me. However, even this tiny bit was not evident in the 106 under any conditions I could hand it. So, point for Tak and its claims on this score.

How about 'sharpness' and 'reach' in the 106? M-42 and the Trapezium, yet another 'standard' test of resolving ability, was aced by the 106. Depending on seeing conditions, it displayed the tougher components of the Trapezium with ease, and resolved them beautifully and with the same crisp definition that was consistent with its planetary performance. 'Reach' was also superb, with Sigma Orionis' multiple components spilt easily at comparatively low power, and with (usual) casual star test on these doubles showing distinct Airy discs rather than a meld. An impressive performer on deep sky for a four inch objective.

My conclusion is that there is no four inch doublet I have had the chance to own or use that can keep up with the 106.

The balance sheet is harder to write out when the 106 is stacked up against a first rate triplet. Takahashi claims that the 106 sets "a new standard for innovation and color correction." Well, I can't say that this is true - nor can I say that it is not fact. The reason for that is itself rather interesting, and goes beyond just this review into some basic design issues.

In telescope design, as in all other products, every design is a result of compromise. Short, fast triplet refractors can be designed and built to provide all of the advantages discussed in the beginning of this review, but can also compete very well with their longer, but otherwise 'equal' brothers in all but one area. A longer focal length triplet design, even using the same glass types and other features of a its shorter brothers, can be better corrected for visual use.

For example, the AP 130 f/6 is a great visual scope that is designed, much like the AP Traveler, as an photographic astrograph with the best possible visual performance that is consistent with maintaining the ability to produce fine images. It is no slouch in the visual area, and it is a very handy scope to use. At the same time, in the recent past, AP offered a five inch alternative using the same glass type as the f/6 but optimized for visual use in general and planetary/lunar in particular - the AP 130 f/8.35- which trades off it 'ultimate' performance as a lunar/planetary instrument against the advantages we have already discussed that 'favor' the shorter, faster apos in today's market .

The 130 f/8.35 (reviewed elsewhere at this site by its owner) is basically the 'heart of the AP 155 f/7' (to paraphrase the Tak manual above) used to produce an apo in the classic f/8 to f/9 focal ratio but using the latest glass type (FPL53) and the design of the newer AP refractors rather than the slightly older EDT series to produce a no-compromise 'planet killer.' Those who have tried this scope and compared it to its f/6 brother do not claim the difference is substantial, but for the connoisseur, the f/8.35 is the better visual performer. (I have heard similar comments made as to the new TMB 105/650 versus it longer brother, the TMB 100 f/8. The former is a great performer, but the latter still a tad better performing on lunar/planetary. BTW, Tom Back is well aware of the advantages of the 'classic' focal length for the best possible performance, and has stated on various groups that he designed the larger aperture TMBs as f/8 refractors - the 152 and 175 - and designed the 203 and 229s as f/9 instruments.)

So all of this rambling brings us to the crunch in this review. I did a fairly detailed 'put the 106 on one side of the Giro-2 and triplet X on the other" evaluation. The results were not that easy to call - nor could they be under these conditions - because I was not only testing one very fast apo against at least one other, but because of the very nature of the 'competitors' themselves.

I have been using the 106 for a few weeks now. The Giro-2 provides a wonderful means of 'side-by-side' testing, quite literally as you can see from the attached photos, as the two 'comparison' scopes can be placed side by side and trained on the same targets. Diagonals and eps can be switched from one to the other with ease, to keep the variables that might impact on the evaluation of the scope (rather than another part of the observing system) to a minimum. However, the two scopes that the 106 were compared to for the purpose of this review were two very different critters.

The 106 is an f/5 modified Petzval design, using two fluorite elements to produce a short, fast, but as perfectly-corrected as possible visual and photographic astrograph. I had two top-of the-line triplets available to me to test it against, the 105 f/5.9 AP Traveler and the TMB 100 f/8. And that is where the problem arose, as one of the two top-of-the-line triplets available for comparison to the Tak quadruplet had the 'unfair advantage' of that classic f/8 focal ratio while the other was nearly as fast as the Tak.

With one or the other of the two triplets on the far side of the Giro-2 facing the Tak, some things were nearly identical, and some were quickly seen to be different. The first thing that became easy to determine was color correction. As I noted above, the 106 has marvelous color correction. But both the AP and TMB are right up there with the Tak, and I could detect no color in either of these two triplets - a dead heat to my eye (or eyes, using a binoviewer.) on color correction.

Now the contrast and 'crispness' testing, my most important personal criteria. The Tak against the AP first:

The Tak is very, very crisp and 'contrasty' on lunar/planetary. Some of the views are just breathtaking for contrast and clarity. The AP is also very good, but 'warmer' in tone and not quite as 'stark' in its definition, particularly on a full and bright lunar disk than the Tak quadruplet. On Jupiter, the performance of the Tak is clearly a bit ahead, the contrast here definitely better in the Tak than in the AP. On nights of exceptional seeing (and we had one last week that my friend Brian was raving about - as he should since he had the Takahashi Mewlon 250 up on Jupiter) the Tak was clearly able to resolve more detail and provide a 'crisper' view than the AP. The same held true for lunar viewing, the Tak was able to provide more detail under high power of the more 'delicate' features such as crater walls and the "Highlands" than the AP.

When the Extender Q was plugged into the back of the Tak, the question of which offered superior lunar/planetary views or was better at the game of 'split the binary' became a no-contest. The Extender Q (an image amplifier designed with this telescope in mind) raised the already fine ability of the 106 to a level that was all the manual had promised. It gave the Tak the classic 'unfair advantage' over the now shorter focal length AP.

Shift over to my favorite deep sky wonder (M42) and the 'test stars' are all there and easy to pick out in both scopes. However, the background is blacker, and what my wife calls the 'powdered sugar' effect crisper in the Tak than the AP.

Now before the Holy War starts, and I know it will despite whatever I say to ameliorate it, the AP Traveler is a wonderful telescope, and it does not need me as its apologist. However, and while I agree that my testing is not 'scientific' (see my recent article on my philosophy of telescope testing and reviews) but subjective, the view through the eyepiece of the Tak when compared to the AP did show better contrast, 'crisper' definition, and would be my choice of the two as a visual observing platform.

Is the Tak's superior contrast and 'sharpness' a great leap over the AP? No, both are superb, but the edge is there to be seen in the Tak and consistently so which resolves this contest (if one wants to call it that) in favor of the Tak Quadruplet over the oil-spaced AP triplet.

The 100 TMB f/8 is a tougher antagonist. The TMB has the 'unfair' advantage of the longer focal length, and is designed as a 'no compromise' lunar/planetary scope. With the TMB on the other side of the Giro-2, the fight (depending on the target) was either a draw or (in several cases) a victory for the TMB.

The TMB provided the same, superb and rather stark 'black and white' image of the Moon that drew me to the 106 in the first place. (Yes, I am - as many have said in the past, and not always in relation to astronomy- a Lunatic.) When it came to ultimate resolving power on lunar targets, the TMB held an edge. Shifting to Jupiter, the same pattern emerged, with much less of a difference however as this is where the very slight difference in aperture rears its head.

The 106 Tak and the 100 TMB 'evened out' on doubles and other targets, leading me to conclude that the slightly 'superior' focal ratio and optics of the TMB was balanced by the slightly larger aperture and almost as good or equal optics of the Tak.

So the 'winner' in theory here was the TMB, but as a function of its inherent advantage in design (longer focal ratio) and, I would also assume, because of Tom Back's almost fanatical commitment to making sure that the scopes bearing his name ship out to his customers with the best possible optics. Indeed, even with the Extender Q plugged into the back of the 106, the TMB held its slight, but undeniable edge.

The test I would really like to perform would be the Tak 106 versus the TMB 105/650. Fortunately, I have been in contact with Tom and Mike at Astronomics, who have promised that if I can't find an owner in the area to try the two side by side, that I can borrow one to see what happens. I will post an update as soon as we do so.


The manual promises a lot from the Tak 106. While I am not prepared to say that it delivered at the rarified level of its maker's prose, it impressed me as a superb four inch refractor, and if asked which four inch 'fast' refractor was the pick of the litter today, the laurel would go to this scope. Drawbacks? Price is equal to its nearest competitor (the AP) when you through in the larger focuser, the field flattener, and the rotating camera angle adjuster.

Rivals? For purely visual, only the longer focal ratio apos discussed above.

The real 'joker' in the equation? The newest entry into the market, the Takahashi Sky 90, a tiny wonder. But that is for another review and update coming out soon.

As always, thank you for allowing me to give you my thoughts on a very nice product.

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