Like the TSA-120, which has exactly the same optics, the TSA-120FT is equipped with an triplet ED apochromatic lens with a diameter of 120 mm and F/7.5 focal ratio, mounted in a 3-group cell. The latter ensures good stability of the optomechanical chain in the face of the usual constraints of transport and in the face of significant variations in temperature of use. It is equipped with a retractable dew shield.

The lens has been designed to achieve a very high level of performance in observation and photography. The chromatic aberration in short wavelengths (blue and violet) is reduced by one third compared to the old FS-102/FS-128 with Fluorite lens. The Strehl ratio at optimal wavelengths of human vision is almost perfect, at 99.2%, equivalent to that of the TOA series.

The TSA-120 is therefore a lightweight, compact and economical refractor, whose performance is similar to that of the TOA, Takahashi's flagship models and recognized as among the best in the world.

On this TSA-120FT version, the original focuser is replaced by a Starlight Instruments Feather Touch 3.0" model engraved "Made for Takahashi", equipped with a 1/10 microfocuser. The adaptation has been optimised so that the accessory mounts remain identical to the original version. The oversized focuser allows for robust assemblies with large cameras and filter wheels.

The addition of the optional field corrector allows native focus imaging. The TOA-35 reducer (F/5.25) makes it more comfortable in deep sky photography. All assemblies meet the rigidity and flexibility requirements of new imaging devices, such as digital cameras and the latest generation of CCD cameras.

Optical characteristics
Optical design ED Triplet Super ApochromatD
Lens cell Air-spaced triplet. 3 lenses/3 groups. 1 S-FPL53 ED lens in the middle.
Coatings Hard multicoatings
Diameter 120 mm
At prime focus
Focal length 900 mm
Focal ratio F/7.5
Metal back distance 227.5 mm
With TOA-35FL field corrector
Focal length 882 mm
Focal ratio F/7.3
Image circle diameter 40 mm
Metal back distance 117.5 mm
With TOA-35RD focal reducer
Focal length 672 mm
Focal ratio F/5.6
Image circle diameter 40 mm
Metal back distance 62.5 mm
With EXT-ED1.5X focal extender
Focal length 1350 mm
Focal ratio F/11.3
Image circle diameter 44 mm
Metal back distance 117.5 mm
Mechanical characteristics
Length of the optical tube -
Diameter of the optical tube 125 mm
Diameter of the dew shield 160 mm
Weight 6.7 kg
Focuser Starlight Instruments Feather Touch 3.0'' rack-and-pinion focuser

Spot-diagram of Takahashi TSA-120 at prime focus

Spot-diagram of Takahashi TSA-120 with TOA-35FL field corrector

Spot-diagram of Takahashi TSA-120 with TOA-35RD focal reducer



System-chart of Takahashi TSA-120FT refractor Télécharger

Instruction manuals

Instruction manual of Takahashi TSA-120FT refractor Télécharger
TSA-120 refractor with Feather Touch
TSA-120 refractor with Feather Touch