Takahashi TSA-120 120mm (4.7") Triplet Apochromat Optical Tube Assembly (OTA)

Takahashi TSA-120 120mm (4.7") Triplet Apochromat Optical Tube Assembly (OTA)

Due to high demand and global product shortages due to the pandemic, please call for availability.

The TSA series is a member of Takahashi’s line of triplet refractors. In the TSA design, an ED glass lens is placed between two lenses, with air spacing in between. The resulting system achieves a high level of apochromatic performance for both visual observation and imaging.

The TSA-120 is a 120 mm apochromatic f/7.5 refractor with a focal length of 900 mm. It features a retractable lens hood and a 2.7 inch rack and pinion focuser. The TSA is compatible with several flatteners, reducers and extenders, including the TOA-35 Reducer, which converts the telescope to a f/5.3 imaging platform with a 44 mm image circle.

The TSA-120 is the second in the new TSA line of Takahashi triplet apochromats. The color free performance will delight the lunar, planetary and deep sky observer with very high contrast images and pin point stars.

Not only is the TSA-120 a great visual instrument, it can be converted into a flat field f/7.3 or an f/5.3 wide field imaging platform for a CCD camera or digital SLR. The addition of the optional camera angle adjuster allows the image to be rotated 360° without loss of focus. The camera angle adjuster is also very handy for visual applications to position the ocular or bino viewer in the best most comfortable position.

The TSA-120 is a fairly compact, high quality, apochromatic, versatile Takahashi, made for the refractor enthusiast who wants a very high quality instrument in a relatively compact package.

Note: Takahashi optical tubes are sold without tube holder (rings), finderscope, star diagonal, eyepiece, reducer, flattener, extender, mount and tripod. These extra items are sold separately.

Shipping Notice: These high-precision scopes must be shipped by air for the full warranty to apply. Air shipping charges are not included in our price, and will be added to your bill. We would be happy to quote shipping charges.


  • Newly designed triplet Apochromat
  • Very high color correction, produces color-free images
  • 2.7" focuser for stable focusing, will accommodate heavy CCD cameras or bino viewers
  • Enhanced back focus of 227.5mm (8.96") allows the use of any bino viewer with ease
  • Supplied with rigid 72mm long extension tubes to assure deflection free focusing
  • Knife-edge baffles and slightly oversized tube deliver very high contrast


  • Objective: New design triplet apochromat
  • Aperture: 120mm (4.7")
  • Focal Length: 900mm (35.4")
  • Focal Ratio: f/7.5
  • Focuser Size: 68.6mm (2.7")
  • Back Focus: 227.5mm (8.96")
  • Main Tube Diameter: 125mm (4.92")
  • Length: 870mm (34.3") (lens shade collapsed)
  • Weight: 6.7kg (14.8lbs)
  • Packing: triple carton (maximum protection)
  • Five year manufacturer warranty

Optional TOA-35 FL Field Flattener

  • Focal Ratio: f/7.3
  • Focal Length: 880mm (31.5")
  • Image Circle: 40mm
  • Back Focus: 117.5mm (4.63")
  • Sold separately

Optional TOA-35 RD Reducer

  • Focal Ratio: f/5.3
  • Focal Length: 635mm (25")
  • Image Circle: 44mm
  • Back Focus: 56.2mm (2.21")
  • Sold separately