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Takahashi TSA-120 120mm (4.7") Triplet Apochromat Optical Tube Assembly (OTA)
Takahashi TSA-120 O.T.A

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

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Your Price: CAD6,723.77
Special Order, Usually ships in 5-7 Business Days, If back ordered, ETA 3-4 weeks
Part Number:TTK12010

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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.

Optical Tube Assembly only (mount, tripod, tube holder and finder sold separately).

Tube Weight of the OTA is only 12.5lbs!

  • Second TSA triplet apochromat
  • Very high order of color correction
  • Compact design only 28” long collapsed
  • Long back focus 227mm [8.93”] to accommodate bino viewers and any 2” diagonal
  • Supplied with 2” and 1/1/4” accessories and extension tubes
  • Quick release finder bracket included
  • Knife edge baffles are standard for highest contrast

The TSA-120 is the second triplet apochromat in the TSA Series. Its superb color correction will provide high contrast images with pin point stars across the field.

The compact size of 28” allows the TSA-120 to be easily transported to remote sites.

The TSA-120 is a great scope for imaging. The TOA 35 flattener converts the 120 into an f/7.3 882mm flat field 2.6º instrument and the reducer changes it to an f/5.6 672mm



Focal Length900mm
Focal RatioF/7.5
Optical DesignTriplet ED apo
CoatingBroad band multi-layer anti-reflection

Mechanical Specs

Diameter of main tube: 125mmø
Diameter of dew shield [sliding]: 713mm <-->[28”]
Weight of OTA7 kgs/15.4 lbs
Back focus: 227.5mm [8.93”]

TOA-35 Flattener

Focal Length882mm
Focal Ratiof/7.3
Optical performance 7 micron RMS-spot to 20mm off-axist
Image Circle: 40mmø
Image Field: 2.6ºø diameter

TOA-35 Reducer

Focal Length672mm
Focal Ratiof/5.6
Optical performance 4 microns RMS-spot on axis
6 microns 10mm off-axis
13 microns 20mm off-axis
40mmø/3.4º field

Telescope Specifications 

TSA-120 System Chart

What's in the Box

  • Tube assembly
  • MEF fine focuser
  • Finder quick release bracket
  • 2” compression ring ocular adapter
  • 1 ¼” compression ring adapter w/ coupling
  • 2 ea. 72mm extension tubes
  • Metal focuser rear cover and 2” sleeve

Based on Astronomy magazine’s telescope "report cards",
scopes of this size and type generally perform as follows . . .

Terrestrial Observation: No
Lunar Observation: Great
Planetary Observation: Very Good
Binary and Star Cluster Observation: Very Good
Galaxy and Nebula Observation: Good
Photography: Yes
Terrestrial Photography: No
Lunar Photography: Yes
Planetary Photography: Yes
Star Cluster / Nebula / Galaxy Photography: Yes

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