PrimaLuceLab PLUS 125 mm Mounting Clamps
125 mm clamps compatible with the TSA-120. Check the number of clamps included and make sure to use a mounting plate that fits your mount.
CHF 250.66
Takahashi TSA-120 telescope with a 120 mm ED triplet lens, native focal length of 900 mm at F/D 7.5. Rack-and-pinion focusing.
CHF 4'198.00incl. Swiss VAT
Part Number TTK12010
Will be ordered for you
Delivery time: 5 to 7 business days
Estimated shipping: Between November 23 and 24, 2026
The Takahashi TSA-120 is an apochromatic telescope designed for astronomical observation and photography. Its 120 mm objective lens consists of three air-spaced elements, one of which is made of ED S-FPL53 glass. This design reduces chromatic aberration to preserve sharp detail. At its native focal length, the 900 mm focal length corresponds to an F/D ratio of 7.5.
The three-group barrel is designed to maintain optomechanical stability during transport and in the face of temperature fluctuations during use.
The rack-and-pinion focus mechanism allows you to adjust the focus to match your observing accessories or camera mount. The 125-mm-diameter outer tube allows you to choose a mount that is compatible with this telescope.
The optional TOA-35FL corrector offers a focal length of 882 mm and a corrected image circle of 40 mm. The TOA-35RD reducer is also among the photographic accessories available for the TSA-120. The choice of rings and the distance to the sensor depends on the corrector or reducer selected.
This part number refers to the optical tube, including its objective lens and focusing system. Select the mounting, pointing, and observation or photography accessories that are appropriate for your use separately.
Takahashi TSA-120 Overview and Documentation
The Takahashi TSA-120 is an apochromatic triplet refractor with an ED lens featuring a 120 mm aperture and a 900 mm focal length (f/7.5), designed primarily for deep-sky astrophotography. Its focal length is ideal for observing galaxies (M51, M101, the Leo Triplet), planetary nebulae such as M27, and globular clusters, with a good level of detail. At f/7.5, its classic aperture-to-focal-length ratio requires slightly longer exposure times, but in exchange delivers very fine star points.
With an APS-C camera featuring 3.76 µm pixels (Sony IMX571 sensor), you get approximately 0.86″ per pixel for a field of view of 1.5° × 1°. This is a fine resolution: under average turbulence, 2×2 pixel binning or a 0.7× reducer will produce rounder stars. With the 0.7× reducer, the resolution increases to 1.23″ per pixel and a field of view of 2.1° × 1.4°.
Yes, whenever you're using an APS-C or full-frame sensor: like any uncorrected triplet lens, it has a slight field curvature that stretches the stars in the corners. Dedicated correctors: Takahashi 35FL: 50.8 mm field corrector for TSA/TOA ; Takahashi TOA-35 - 0.7× focal reducer for TSA/TOA (equivalent focal length of 630 mm, f/5.2).
227.5 mm (metal back); 117.5 mm with TOA-35FL; 62.5 mm with TOA-35RD 0.7×. This focal length is measured from the thread to the sensor, including rings, filter wheel, and filter drawer: adhering to this measurement down to the millimeter ensures that stars remain round in the corners.
The tube weighs about 6.1 kg; with the camera, filter wheel, and guide scope, expect it to weigh around 7.6 kg: an HEQ5-R Pro-class mount provides plenty of headroom. A refractor requires no collimation: once balanced, it’s ready to use as soon as it reaches operating temperature. At 87 cm long, it requires a decent-sized trunk.
Yes, as a bonus: with an angled mirror and an eyepiece, it provides high-contrast, color-accurate images of the Moon, the planets, and double stars, up to about 240×.
Here are a few accessories we've selected for this model, depending on your needs.
125 mm clamps compatible with the TSA-120. Check the number of clamps included and make sure to use a mounting plate that fits your mount.
Choose the PrimaLuce PLUS Vixen 240 mm tail if your mount has a Vixen clamp. Use the recommended PrimaLuce PLUS clamps, sold separately. Check the length, spacing, and balance. Also check the clearance for the eyepiece holder and accessories. An alternative to the Losmandy version.
PrimaLuce PLUS Losmandy 240 mm tail—choose this if your mount has a Losmandy clamp. Use with the recommended PrimaLuce PLUS clamps, sold separately. Check the length, spacing, and balance. Also check the clearance for the eyepiece holder and accessories. An alternative to the Vixen version.
TOA-35 reducer for a shorter focal length, an alternative to the 35FL corrector. You will need the CAA-M, the CA Ring 150, and the appropriate adapters for mounting.
35FL field flattener, an alternative to the TOA-35 reducer. Check the connections and distances based on your telescope's configuration.
1.5× ED extender to increase the focal length. For photography, Takahashi recommends the TOA-35 corrector; check the connections and do not place a filter on the eyepiece end of the extender.
Motorized eyepiece holder that replaces the original one. Be sure to use the dedicated adapter PL3600296 and check the connections, the corrector, the load, and the draw of your mount.
190 mm motorized flat panel for a 160 mm anti-fog screen. Check the mounting, alignment, travel, cables, and that the control unit is compatible with your system.
Recommended diameter: 200 mm. Check the measurement and the mounting.
