Takahashi FCT-L 0.8x Focal Reducer
CHF 817.46
Takahashi FC-100DZ 100 mm telescope, 800 mm focal length at f/8, 50.8 mm rack. Part number TFK10300, configuration includes a finder scope and mount.
CHF 3'298.00incl. Swiss VAT
Part Number TFK10300
Will be ordered for you
Delivery time: 5 to 7 business days
Estimated shipping: Between November 23 and 24, 2026
The Takahashi FC-100DZ combines a 100-mm apochromatic objective with a native focal length of 800 mm, resulting in an f/8 ratio. The air-spaced doublet features an internal fluorite lens and is coated with a hard multi-layer coating.
The DZ features a dedicated 800-mm focal-length lens and uses the DF's 50.8-mm rack. Its retractable dew shield reduces the tube length from 840 to 770 mm for storage.
The FC/FS MFL1.04X multi-flattener and the 76D-RD and FC-35RD reducers are available as options. The selection of rings and the distance to the sensor depends on the specific telescope and corrector chosen.
The researcher helps with alignment, while the collar holds the tube in place on a suitable mount.
Choose a mount that is compatible with your equipment, and check that the assembly is balanced and securely fastened.
Takahashi FC-100DZ Documentation
The Takahashi FCT-L 0.8x Focal Reducer allows the FC-100DZ to be used at 636 mm and f/6.4, with an image circle of 44 mm.
The Takahashi FCT-L 0.99x Field Corrector flattens the field while maintaining a focal length of 791 mm at f/7.9, with an image circle of 55 mm.
These two accessories are sold separately and use the FCT-L CO 114D ring, which is compatible with the FC-100DZ. The assembly also includes the Camera Angle Adjuster M. When using the FCT-L 0.99x corrector, the M72 L52 extension tube is required as an additional component for the FC-100DZ.
For a CMOS camera, select the M72-M48 or M72-M54 end adapter that matches the camera’s connection. The sensor plane must be located 55 mm from the base of the thread on the camera side of this adapter. Refer to the Takahashi diagram for the selected converter for the order of the parts and the necessary connections.
The Takahashi FC-100DZ is a 100-mm-aperture fluorite doublet refractor with a focal length of 800 mm (f/8), 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/8, which is relatively slow for deep-sky imaging, it benefits from being used with a focal reducer.
With an APS-C camera featuring 3.76 µm pixels (Sony IMX571 sensor), you get approximately 0.97″ per pixel for a field of view of 1.7° × 1.1°. This is a fine resolution: under moderate turbulence, 2×2 pixel binning or a reducer will produce rounder stars. With the 0.66× reducer, the resolution increases to 1.47″ per pixel and a field of view of 2.6° × 1.7°.
Yes, whenever you're using an APS-C or full-frame sensor: like any uncorrected doublet lens, it has a slight field curvature that stretches the stars in the corners. Dedicated correctors: Takahashi TKA00582: 1.04x MFL FC/FS Corrector ; Takahashi 76D RD: Focal Reducer for FC Telescopes ; Takahashi TKA19580 - FC-35 0.66× focal reducer (equivalent focal length of 528 mm, f/5.3); Takahashi FCT-L 0.8x Focal Reducer (equivalent focal length of 640 mm, f/6.4); Takahashi FCT-L 0.99x Field Corrector.
225 mm (metal back); 71.2 mm with MFL 1.04×; 68.8 mm with FC-35RD 0.66×; 55 mm with FCT-L 0.99×/0.8×. This focal length is measured from the thread to the sensor, including the 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 3.9 kg; with the camera, filter wheel, and guide scope, expect it to weigh around 5.4 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 77 cm long, it fits easily in the 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 200× magnification.
Here are a few accessories we've selected for this model, depending on your needs.
Extender-Q 1.6× to increase the focal length and magnification. Check the connections according to the Takahashi diagram; the 50.8 mm TKA00596 adapter may be required depending on the mount.
120 mm heating strip for a 124 mm defogger. Check its location and clearance; a 12 V power supply or controller with an RCA connector and sufficient power must be provided separately.
Recommended diameter: 125 mm. Check the measurement and the mounting.
Recommended diameter: 150 mm. Check the measurement and the mounting.
