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Home > Reviews > Telescopes > Refractors > Takahashi’s TSA-102 Refractor

Takahashi’s TSA-102 Refractor
By Ralph Aguirre - 11/27/2010

Takahashi’s TSA-102 Triplet Super Apochromatic Refractor on a Vixen GP-DX Equatorial Mount


I remember when I was 10 years old, right after the Apollo 11 astronauts landed on the moon, I got my first telescope. It was a 60mm Tasco, 700mm Fl, 350x refractor. It had an alt-azimuth yoke mount, metal legs, a 2x Barlow, diagonal, sun and moon filters and a white solar projection screen. Every opportunity I had to take that scope out, even in the day time, I would. Id look for the brightest stars, the few planets I could spot, Jupiter and Saturn, and never once thought I needed more than what I was using at that time, to have fun with.
From time to time, my mom would wake me up and tell me there's something in the sky that's real bright, or something over the neighbor's house in the sky, so I'd get up and set my scope up in the front yard, and take a look. I found Venus and Jupiter that way, and a few comets like Comet Bennett, Comet Kohoutek, and Comet West. She always wanted me to learn about the sky, so I could tell her what I was seeing. It was her inspiration that always kept me interested in the night skies.
I kept that telescope for over a decade, and it wasn't until I was going to college, that I upgraded my scope to an 80mm Vixen on an alt-azimuth mouth. Optically, this was worlds better than my little 60mm Tasco refractor. With the Vixen I watched Haley's comet come toward earth from my apartment's balcony with my wife, and always used it whenever astronomical events were happening in the sky.
Nearly a decade after that, I bought a 90mm Meade 395 on an equatorial mount. My wife and I would spend nights on our new patio in our new home, just watching the skies at night. I saw the Shoemaker Levy 9 collision with that scope, and comet Hale-Bopp. Fast forward nearly 15 more years, and 5 more refractors later, and I found myself purchasing an excellent TSA-102 on Astromart.

The first thing I notice about the TSA-102 is that it is a very solid instrument. Typical with other Takahashi's I've owned, the TSA was build without compromise, with a very solid optical tube, dew shield and focuser. This particular scope came with a feathertouch focuser installed by the previous owner. Although I prefer Takahashi's 10:1 microfocuser for overall feel, the smooth movement of the 2.7" draw tube and how well the focusing mechanism works using this particular feathertouch focuser is exceptional and as good as the best feathertouch equipped Takahashi's I've ever used. The feathertouch focuser also compliments the looks of the telescope, adding a solid piece of well made machined aluminum as the focuser.

Feathertouch Focuser, Accessory Ring with Finder Bracket and 50mm RA finder scope, with Camera Angle Adjuster shown

On my particular scope, I installed the much needed Takahashi Camera Angle Adjuster. These rotatable backs are a must for equatorial mount users since repositioning the eyepiece and diagonal is necessary nearly every time the scope moves from one part of the sky to another. With the CAA installed, the entire back of the scope rotates effortlessly, putting the eyepiece at the proper angle for any viewing situation. The rotation of the CAA is very fluid, and doesn't shift the object in the eyepiece when rotating, even at crazy high magnifications.
The scope comes into focus with every eyepiece I have from my 2.5mm Nagler to my 41mm panoptic when using the Camera Angle adjuster, which adds an additional one and three eights of an inch of back focus to the claimed 230mm of backfocus listed. The 2" compression ring adapter is a nice touch also for holding a 2" diagonal in place, with two set screws which is a must to support the heavy 2" Nagler eyepieces I use. The scope also comes with a 2.7" diameter extension tube which is 2 inches in length, but I've never needed to use it since I don't do astrophotography and again, the scope achieves focus with every eyepiece I use without any additional adapters.

Feathertouch Micorfocuser knob shown with Camera Angle Adjuster, 2" adapter with Maxibrite Diagonal inserted with 26mm Nagler

The sliding dew shield is a popular addition on almost every significant new scope on the market, and the TSA is no exception. Unlike my TOA, the TSA has two locking screws holding the dew shield in place instead of three, and the back lip of the TSA dew shield is painted Takahashi green instead of the white paint used on the TOA dew shield. Otherwise, both work flawlessly sliding and locking in place fully extended or fully retracted. There's no slop or wobble as the dew shield slides in or out, which is typical Takahashi quality fit and finish.

Sliding Dewshield fully extended, also showing Telrad mounted on top of the Vixen Tube Ring


Looking down the front of the tube, it's difficult to notice numerous knife edge baffles inside the OTA without using a flashlight because of the dark green coatings on the front objective, make the most of keeping stray light from reflecting anywhere but down the focal cone to the eyepiece.

Business end of the TSA-102 showing the front coatings and displaying its Triplet Super Apochromat Markings


With the dew shield fully retracted, the focuser racked in fully, the OTA with the camera angle adjuster on the back with the 2" adapter installed measures a very compact 28 inches long. With the dew shield extended and a 2" diagonal installed, (I use the AP Maxibrite 2" diagonal,) the length of the scope ready for business measures 34.5 inches again, with the focuser racked in fully.

For storage, I purchased a Tenba tripod case from one of the online Video stores. This seems to be the identical case Tenba was selling for the FS-102, but this particular case doesn't say Takahashi on it, just Tenba. The case can hold a scope up to 33" long inside, which is plenty long for the TSA with a 2" diagonal installed, the Vixen tube rings installed with the Vixen dove tail, a handle I have mounted to the top of the rings and the dew shield retracted. The case is Tenba TTP34 TriPak case MFR # 634-508.

Sideview of TSA-102 inside the Temba TTP34 TriPak case, dewshield retracted with 2" diagonal installed



The white paint finish on the TSA is classic Takahashi, having a thick high gloss excellent uniform quality. These scopes are extremely expensive for a 4" refractor, but you see the reason why in every aspect of the scope, from optical quality to fit and finish. The glossy white paint and green silk screening is a beautiful compliment to the name Takahashi, and the green cast back and focuser, just like the larger TOA's are absolutely flawless in function and appearance.
My scope came with a B-T Technology quick release finder scope bracket. I tried it but now don't use it mostly because the finder is set too far back toward the eyepiece and shifts the weight of the scope too far back for balance on my Vixen GP-DX equatorial mount. The finder mounted that far back also sometimes gets in the way of the main eyepiece, making it difficult to use either when they are on top of each other, when the OTA is in certain positions in the sky. Instead, I use the 4" accessory ring Takashashi sells for their 4" tubes, and mount the same Tak finder bracket I use on my TOA-130. I use a Stellarvue 50mm right angle finder scope with a Televue 20mm Plossl in the eye piece. This is a sharp set up with the rotatable back and helical focuser, and is light years more practical as a finder scope to use, than the excellent Takashasi straight through finder Takashasi sells. This accessory ring / finderscope combination just flat out looks good too, and absolutely compliments the overall look of this beautiful refractor.

Top view of scope showing RA Finder scope with 20mm TV Plossl, Finder bracket and Accessory ring


All of these perfect mechanics and esthetics mean absolutely nothing if the scope doesn't deliver the optical performance we have all come to expect from Takahashi. The TSA-102 delivers on that promises, every time you looks through it, at any object you can get in the eyepiece. Takahashi claims the front lens cell is a three element air spaced design, with an FPL-53 Extra-low Dispersion glass element sandwiched in between two extreme quality crown and flint glass elements. With 1/12th wave accuracy and a minimum airy-disc Strehl ratio of 0.992 the scope delivers the beauty and natural colors of space as you would expect from a scope of this magnitude.

Although I've had this scope for over 2 years now, every time I use it, I'm constantly reminded of how far we have come in the development of the 4" refractors. I have as much fun with this scope under dark moonless skies, as I do in my back yard under full moon conditions, whether I'm splitting double stars, observing the size and colors of star systems, as well as hunting down galaxies, star clusters, nebula's or doing lunar and solar observing.
Even under moderately cloudy skies when I just have to get in some time observing, this scope always delivers stunning views of everything I look at. Atmospheric issues seen to be more of a non issue with the TSA, than other scopes I have, and whether the seeing conditions are much less than ideal, star patterns, planetary and lunar observing is always a rewarding experience. Stars are always pin points all the way to the edge field of view, and though my eyepiece collection consists of both Naglers and Panoptics, the new generation of pricey Ethos eyepieces from Televue as well as the excellent Explore Scientific EX100's both deliver rock solid performance right out the extreme edge field of view. The brightest stars, like Vega, and Sirius, glow in their natural white light. Chromatic aberration isn't a word that belongs in any conversation when discussing the TSA refractor. It just doesn't exist, end of subject.
This is the only 4" refractor I've spent enough time with that I can say can compete head on with the optical perfection of the FSQ Takahashi's, delivering absolutely perfect views every time. The TSA inhales magnification much better than the FSQ's, mostly due to the higher focal length of the TSA, which can be pushed to 100x per inch of aperture more effortlessly, since the TSA doesn't require dedicated diagonals and extenders to achieve focus, which the FSQ's do.
Although I seldom care to push the scope very hard, splitting the double double above 300x gives perfect separation of all four stars with pin point precision that few scopes can achieve. The optics can hold brilliant Sirius so steady, that the pup can be seen above 100x on clear nights of seeing. On extremely rare nights of excellent seeing conditions, I can't hit the magnification ceiling with this scope. I've put my big barlow in front of my AP diagonal on one rare night of perfect seeing conditions, and inserted my 5mm Nagler into the diagonal, and viewed Saturn at over 400x, and the scope would not break down. The limiting factor always seems to be the ability to gather enough light to make extreme high power practical, not because the optics break down.
Like just about every other telescope I own, this scope, seems to be more practical in the 20x to 200x range, where I can use my 41 Panoptic at 20x to deliver breathtaking views of the Andromeda galaxy or the Double Cluster in Perseus. The diamond effect stars have when viewing the entire Pleiades in one field of view under dark skies, will leave you just awestruck in how magical that cluster appears. Every star is an absolute pin point, yet they all sparkle with brilliance in the eyepiece, the way only the finest refractors can present this cluster. The great Orion nebula is textbook perfect at high power, where the trapezium jumps out at you even with just 4 inches of aperture. The E and F stars can easily be seen when the seeing conditions are better than average. Using my 41 Panoptic, and the entire belt or sword of Orion can be seen in one field of view, something I think every true astronomer should experience through optics like these under clear dark cold winter skies. Like my TOA, larger stars under higher power become perfect glowing round balls of red, blue, orange or white lights.
The velvety black background skies which have become common to Takahashi Fluorite refractors continue to be true with the TSA also. The wispy spiral arms of the whirl pool galaxy or the eerie effect of the helix nebula when viewed through the TSA seem to give you the impression that you are looking through more aperture than just 4 inches of perfect optics.
This is where the appeal of these 4" triplets really come onto their own. It's not the size of the aperture that makes these scopes spectacular visual masterpieces, its because they have the ability to gather up so much sky in one field of view, and present it to you in an absolutely visual experience. Long focal length telescopes can't frame the entire Double Cluster in one field of view, or the entire Pleiades, or Andromeda, the way these shorter refractors can. Long focal length scopes can't gather up 3 degrees or more of the sky in one field of view, to see the full length of a comets traveling beside and NGC or messier objects, or frame two planets side by side, like we are currently experiencing with Jupiter and Neptune.
On planetary viewing, the TSA cuts right through the bright glow of the Venus's brilliance and delivers a perfect crisp crescent suspended in space. The Polar caps on Mars can be picked out with the TSA at higher power and some surface details can be seen also. With better seeing conditions, the GRS on Jupiter is easy to see, and the white fluffy festoons are easy to make out. On Saturn the shadow of the rings cast onto the planets surface are noticeable, as well as different shades of colors on the planets surface. Since the planet is going through its edge-on ring angle as viewed from Earth, I haven't been able to evaluate the rings details with the scope. Compared to larger achromatic refractors on the planets, the views through the TSA are whiter in color with more contras. The perimeter of the planets surface details are much more crisp in the TSA. Even Uranus and Neptune can be seen if you can find them, but it's these planets where pushing the optics to 300x or above, brings out perfectly round blue balls of both planets.


TSA-102 fully loaded, on Vixens proven rock solid GP-DX Equatorial Mount


As perfect as my FS-102 was to me, the TSA is a notch above in visual performance. When the seeing conditions are there, the TSA at high powers delivers just slightly cleaner star fields and whiter stars. This isn't obvious unless you do a side by side with its Fluorite cousin.
This brings up another important necessity required to get the most out a scope of this caliber. The mount you choose should be solid enough and track well enough, so you can at times, push these optics to 80x to 100x per inch of aperture. My Vixen GP-DX has always been my small rock solid light weight equatorial mount for every 4" refractor I've ever owned. The mount has legs long enough using the Hal 110 aluminum tripod that you never finding yourself stooping down when you don't want to. Extending the legs to their fully open position makes the mount too tall for the TSA for me, unless you expect to stand for a night of viewing.
The tracking on the mount is excellent also, and when properly polar aligned, can hold an object in the eyepiece indefinitely, even during high power viewing. I like this mount also because it has slow motion manual controls, and can be used without power, just moving the RA knob periodically for tracking, something you can't do with a GM8, my other favorite small OTA mount. The slow motions controls are excellent also, and makes scanning the surface of the moon for example, a true space walk, using the hand controller, or just for centering an object in the eyepiece.

A few final notes about comparisons or reviews, that we all have to take into consideration, is the quality of your diagonal and eyepieces. An older eyepiece that isn't multicoated, or isn't contras enhanced or one that isn't sharp out to the edges, can give you a false negative about an otherwise excellent telescope like the TSA. Poor quality diagonals can break down your optics as magnifications increase also. Following the sky conditions, using the Clear Sky Clock for your area for seeing conditions, can make or break a night if you're expecting to do high power planetary viewing. Checking the overhead jet streams in your area is also another factor, in getting the most out of a night of solid viewing.


Ready for a night of fun times with my exceptional 4" Refractor


Would I consider the TSA-102 the perfect back yard telescope? For me, it would be a close call, because there probably isn't one scope that can do everything well. The cost of these scopes is ridiculous, and under my city conditions, my Carbon Fiber C8 XLT pulls in deep space in my back yard with much more authority after about half an hr of cool down, than the TSA can. Visually, my CF-C8 XLT can deliver pin point stars right out to the edge of its field of view, but falls victim to the TSA when trying to split the tightest double stars. Then the TSA easily walks away from the SCT and as good as I want think the SCT is, when splitting the tightest doubles, its not even close. In wide field views, the smaller 4" refractors are hard to beat, giving as much as 3.4 degrees field of view using my 41 Panoptic.
As far as my favorite scope, the TSA is the one for me. My TV-85 could be more fun, being even easier to set up and use, but the TSA is my favorite scope, mostly because despite the TSA still being a small scope, it acts much closer to my TOA-130 in optical performance than it does to a 4" scope. Setting it up, looking at it, looking through it, and just having fun with it, reminds me of when I was a kid living at home unaware of everything in the world around me, and the only thing that mattered to me was how much fun I could have.
At about 16 pounds fully loaded sitting on the mount, the TSA is simple to set up and use, lightweight, and just plain ol' fun to use. I don't have to be serious with this scope. I don't need a perfect dark night to enjoy these exceptional optics, I can have just as much fun in my back yard splitting stars under full moon conditions as I can under dark moonless skies hrs away from home. For that reason alone, the TSA is my favorite scope, and the one I find myself using the most. Astronomy is a fun rewarding relaxing hobby. We should all have at least one scope that we can easily set up and get lost in space with. For me, that scope is my TSA-102.

Clear skies and always keep looking up!

by Ralph Aguirre
AA6WW
Sacramento, California

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