Takahashi TSA-120 4.7" F/7.5 Ortho-Apochromat triplet refractor OTA


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This Takahashi TSA-120 4.72" ED triplet refractor puts true-color "super apochromat" optical excellence in a portable 15.4 lb. package . . .
Our Product #: TSA120
Takahashi Product #: TSA0120
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Product Description

This Takahashi refractor optical tube has:

• 120mm (4.72") f/7.5 Ortho-Apochromat ED triplet optics
• 2.7" rack and pinion focuser with 1.25" eyepiece adapter
• retractable dew shield
• 227.5mm of back focus for CCD and film imaging
• state-of-the-art optical performance, exceeding even fluorite scopes
• 5-year warranty

    The Takahashi TSA-120 refractor provides exceptionally high optical and mechanical quality for the serious visual observer and astrophotographer who needs portable optics. The TSA-120 is exceptional for observing and imaging within the solar system. Its images of subtle lunar and planetary details are sharp, with realistic and highly saturated color. They are free from chromatic aberration's violet haze of spurious color, thanks to the scope's ED triplet optics. The latest broadband antireflection multicoatings and numerous knife-edge internal baffles assure the maximum image contrast possible.
This 4.72" Takahashi has excellent light transmission and diffraction-free true color images that make it superb for deep space observing and imaging, as well. Binary stars and globular star clusters are particularly well-resolved and vivid, with the contrasting colors of many binary systems showing nicely. The brighter nebulas and galaxies stand out against a very dark sky background.
The f/7.5 focal ratio and 900mm focal length of the TSA-120 are long enough, using a Takahashi 2.8mm ED eyepiece to provide 321x, for high magnification observations of the Moon and planets, yet it will also produce a huge 2.72° field at 18x, using a 2" Takahashi 50mm eyepiece.

This Telescope's Optical and Mechanical Systems . . .

  • Apochromatic triplet ED refractor optics: 4.72" (120mm) aperture, 900mm focal length, f/7.5 Ortho-Apochromatic triplet lens using an FPL-53 ED (Extra-low Dispersion) glass element between two crown glass elements for images that are free from spurious color (chromatic aberration). For more details, click on the "Takahashi triplet lens" icon above.

  • Multicoated optics: Fully coated on all surfaces with multiple layers of broadband antireflection materials for high light transmission and good contrast.

  • Retractable dew shield: Slows the formation of dew on the lens to extend your undisturbed observing time. Also improves visual and photographic contrast by shielding the lens from off-axis ambient light (the neighbor's yard light, moonlight, etc.) For transport, the retractable lens shade keeps the overall length of the optical tube to a very manageable 28" when it is retracted and the visual extension tube removed.

  • Rack and pinion focuser: 2.7" focuser, with a 2" eyepiece/accessory holder that threads into the 2.7" focuser drawtube. A 1.25" compression ring eyepiece/star diagonal holder is also supplied. The non-marring soft nylon compression ring of the 1.25" eyepiece holder won't scratch the barrels of your accessories or star diagonal, as ordinary thumbscrews can. Dual focusing knobs provide precise image control with either hand. The large focus knobs are easy to operate, even while wearing gloves or mittens in cold weather. A large thumbscrew locks the focuser tube in place without image shift for photography.
    A useful photographic accessory would be the Takahashi #CAA102 camera angle adjuster, shown below. This attaches to the 2.7" focuser drawtube in place of the 2" eyepiece holder. It allows the photographic accessory train to be rotated to the most appropriate angle to frame the object being photographed (a landscape format, portrait, or any angle in between) without having to loosen the camera adapter and perhaps lose the correct focus. Once the camera is oriented correctly, a large knob on the side of the adjuster can be tightened to hold the camera in place during the exposure. It is also very handy for visual applications to position the star diagonal or binoviewer at the most comfortable viewing angle.

  • Finderscope mounting point: No finderscope is supplied when this optical tube is bought alone. A flat boss with two mounting bolt holes is provided on the top of the focuser body for mounting an optional Takahashi 7x50mm 6.2° field finder and bracket finderscope.

  • Long back focus: Back focus is a very good 227.5mm, allowing the stacking of a wide variety of CCD cameras, color filter wheels, electric focusers, camera angle adjusters, and film cameras.

  • Optional photographic accessories: Two accessories are available to provide a variety of image scales and sky coverage: a field flattener and a focal reducer. The field flattener (#TOA130FF) reduces the focal ratio slightly (to f/7.3), but gives pinpoint stars to the very edges of a 40mm (2.6°) image circle for virtually unvignetted 35mm/DSLR/large format CCD images.
    The focal reducer (#TOA130R) effectively cuts the focal length to 672mm and the focal ratio to f/5.6. The photographic field is now 3.4°, spread over a 40mm image circle for virtually unvignetted 35mm/DSLR/large format CCD images. A variety of photographic coupling attachments and eyepiece projection photography adapters are also available.

  • Mounting rings: No mounting rings are supplied for the 125mm diameter 15.4 pound optical tube. Several options are available. One is the Takahashi clamshell-type tube holder (#120TH) shown below that is designed specifically for mounting the TSA-120 on a Takahashi EM-11 or larger equatorial mount. The second option is the Takahashi double ring tube holder with bridge (#120DTH) shown below. It can be mounted on a non-Takahashi mount, such as a Celestron CGEM or CGE Pro or Losmandy GM-8 or G-11, by using an optional dovetail plate. This double ring tube holder can also be used to mount the TSA-120 on a Takahashi EM-11 or larger equatorial mount by adding optional Takahashi #TMP106 double ring tube holder mounting plate. A third option is a pair of Parallax split mounting rings (#PFS106), also shown below, for mounting on a non-Takahashi mount, using an optional dovetail plate.

The image above shows the scope with a 7 x 50mm finderscope, mounting bracket, and eyepiece. These accessories are not provided as standard equipment with the optical tube, but are available as optional accessories.

Tech Details

Aperture 4.72"
Binary and Star Cluster Observation Very Good
Focal Length 900mm
Focal Ratio f/7.5
Galaxy and Nebula Observation Good
Highest Useful Magnification 250x
Lunar Observation Great
Weight 15.4 lbs.
Planetary Observation Very Good
Resolution 0.97 arc seconds
Visual Limiting Magnitude 12.9
Warranty 5 years


Review by:
I have the TOA 150, TOA 130, TSA 120, FSQ-85. I have these because I want the best available APO refractors on the market and available without a long wait time or a need to buy them used. There are a lot of great scopes out there but Takahahsi is in the top three best scopes out there. The other two being Astro Physics and TEC. And the TSA 120 is in the top of the class of 120 to 130mm APO refractors. The only one that does better in terms of color correction and crispness is the TOA 130. But The TOA 130 is $2,000 more and a lot more heavy.

The TSA 120 provides the most crisp, clear, true colored views out there in any scope in the 5" class of APO's that I have ever seen. As I said above the only one that does better is the TOA 130. I used to own a TEC 140 . I don't now because when I compared the views between TEC 140 and TSA 120 the TSA scope won. The views were very good in the TEC and the extra 20mm of aperture was noticeable but the TSA provided more of what I call a true color of the stars. In the the TEC the stars were a warmer color especially in the red/orange range. Too warm to me. Where as the TSA captured the true color of the stars. The stars are tack sharp to the edge of the field without a field flattener either.

Visually in the TSA DSO's are a real treat. Even small DSO like Globulars and Planetary Nebulae are resolved in these scopes. Not to the level of a Mewlon 210 or EdgeHD 8" SCT but still enjoyable. And large DSO like open clusters are truly amazing in their color and pinpoint stars to the edge of the field. My two most used scopes are my TSA 120 and my Mewlon 210. I use them on a Losmandy AZ8 with Nexus DSC and encoder kit. I am able to swap between the wide field that the TSA provides and the up close and personal views I get from the Mewlon 210 on small DSO and planets. A real peanut butter and chocolate combination. Or substitute whatever your particular favorite combination is.

For imaging you will want a flattener and/or a focal reducer if your sensor size is over an APS-C/KAF-8300 sensor. Below that the flattener is optional. And imaging with the TSA can be done at its native f/7 without any additional equipment beyond the spacing needed for your camera to take up the 227mm of back focus. I image with the TSA at the native f/7 and it is a nice intermediate scope between the FSQ-85 and the Mewlon 250 I have. I can go deeper on big DSO and get more detail from smaller ones using this configuration. Also important to note is that TEC corrects for visual not AP. So if you are using a Sony sensor then you may get bloated stars in the blue channel. This is a known problem with TEC and Yuri may have addressed it but you will not have any bloat with a TOA.

Bottom line is if you are looking for a top shelf incredibly well corrected 5" APO refractor then the TSA 120 is the best choice on the market today. Both visually and for AP. And one that you can get right now instead of buying used or getting on a waiting list that can be a year long for TEC or likely never for an Astro Physics scope since Roland has closed the list for the AP 130 GTX. (Posted on 10/26/2018)
Review by:
I'm a purely visual observer. After owning a TSA102, I decided I needed a bit more aperture and scoured the earth for the finest 120-130mm APO on the planet. While there are slightly larger apertures available in the ultra-premium APO market for the same class (AP130 Starfire, TOA130, NP127, FS128, etc), nothing can compare in terms of performance/weight ratio. The TSA 120 weighs little more than it's 4" little brother (TSA102), and yet it packs nearly the same punch as the TOA130, which weighs almost twice as much, when mounted correctly. The views through this scope are as you'd expect from anything Takahashi - incredible. Contrast is superb, and the scope outperforms other scopes that are well above it's aperture class. In my opinion, what really makes this scope stand out miles above the others in its field of worthy competitors is the performance to weight ratio. If you're looking for a scope that's close to grab-and-go, but offers enough performance to capture planetary and some deep sky targets, this scope is an excellent choice. (Posted on 10/6/2018)
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