Optical tube Takahashi TSA-120 (OTA) Feather Touch with adapter 50.8

Tube Takahashi TSA-120 (OTA) with Feather Touch Focuser

The Takahashi TSA-120 refractor is midway between the TSA-102 and the TOA-130, replacing the famous FS-128 refractor. The TSA-120 is characterized by its simplicity, versatility and excellent price/performance ratio.

With the same features and specifications as the TSA-102S, it has a 120 mm diameter lens and 900 mm focal length (F/7.5), apochromatic design with three low dispersion (ED) glass elements, retractable hood, excellent mechanics and versatility of use, both for visual observation and photography.

In addition, the TSA-120 is extremely lightweight, weighing only 6.7 kg, which avoids having to use it in large and heavy mounts. Optionally, the same optional accessories as its smaller brother can be used, such as the focal length reducer (F/5.6), field corrector (F/7.3) and focal extender (1.6x).

Equipped with a Feather Touch rack and pinion focuser with a diameter of Ø 3".

Tube length is 990 mm and diameter 125 mm. Diameter of the lens hood: 160 mm. This model is offered with a Ø 3" Feather Touch focuser with Ø 2" output.

Like the TSA-120, from which it inherits exactly the same optics, the TSA-120FT is equipped with a 120 mm diameter triplet ED apochromatic lens with air separation (focal length 900 mm and F/D 7.5), mounted on a 3-group barrel. The latter ensures good stability of the optomechanical chain against the usual stresses of transport and significant temperature variations during use. It is equipped with a retractable anti-fog shield.

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

The TSA-120FT is therefore a lightweight, compact and economical telescope whose performance is close to that of the TOA, flagship models from Takahashi and recognized as some of the best in the world.

In this TSA-120FT version, the original focusing system has been replaced by a Feather Touch 3.0" model from Starlight Instruments with the inscription "Made for Takahashi", equipped with a 1/10 motorized microfocus. The adaptation has been optimized so that the accessory mountings remain identical to those of the original version. The oversized focuser thus allows for robust mounts on the focuser with cameras.

Features

Telescope Takahashi TSA-120FT

Triplet ED Apochromatic Lens

Air-gap lens mount. 3 lenses/3 groups. 1 ED glass lens S-FPL53

Treatments Hard multi-coating

Useful diameter 120 mm

At native focus

Focal length 900 mm

Relative aperture F/D 7.5

Backfocus 227.5 mm

With field corrector TOA-35FL

Focal length 882 mm

Relative aperture F/D 7.3

Diameter of the corrected image circle 40 mm

Backfocus 117.5 mm

With focal length reducer TOA-35RD

Focal length 672 mm

Relative aperture F/D 5.6

Diameter of corrected image circle 40 mm

Backfocus 62.5 mm

With EXT-ED1.5X extender

Focal length 1350 mm

Relative aperture F/D 11.3

Diameter of corrected image circle 44 mm

Backfocus 117.5 mm

Telescope focal point diagram Takahashi TSA-120 in focus

Telescope focus point diagram Takahashi TSA-120 with field corrector TOA-35FL

Telescope focus point diagram Takahashi TSA-120 with focal length reducer TOA-35RD