{"id":20306,"date":"2026-10-23T16:34:02","date_gmt":"2026-10-23T14:34:02","guid":{"rendered":"https:\/\/deep-space-astronomy.ch\/?post_type=product&p=20306"},"modified":"2026-10-26T09:42:31","modified_gmt":"2026-10-26T08:42:31","slug":"correcteur-champ-takahashi-fct-l-099x","status":"publish","type":"product","link":"https:\/\/deep-space-astronomy.ch\/en\/product\/correcteur-champ-takahashi-fct-l-099x\/","title":{"rendered":"Takahashi FCT-L 0.99x Field Corrector"},"content":{"rendered":"

The Takahashi FCT-L 0.99x field corrector flattens the photographic field of the FCT-114DF, FCT-114DS, FC-100DZ, and FC-100DF refractors while changing their focal length only slightly. Its two-element, two-group design provides a 55 mm image circle. It is designed for astrophotography setups that require correction of stars within the field of view while maintaining a focal length close to that of the telescope.<\/p>\n

A focal length that has been almost preserved<\/h3>\n

In the configurations specified by Takahashi, the FCT-114DF and FCT-114DS provide a focal length of 795 mm at f\/7.0. The FC-100DZ reaches 791 mm at f\/7.9, and the FC-100DF reaches 734 mm at f\/7.3. This distinguishes the field corrector from the FCT-L 0.8x reducer: it prioritizes field flattening with minimal focal length variation. The choice between the two accessories therefore depends on the desired photographic setup.<\/p>\n

Takahashi reports a relative illumination of nearly 100 % at the edge of the full field of view with the FCT-114DF. It remains at approximately 90 % with the FCT-114DS, whose inner diameter of the sliding tube results in a gradual decrease toward the edges. For both of these eyepieces, the RMS diameter of the spots is specified as 4.4 \u00b5m on-axis and 5.8 \u00b5m at the edge of the full field of view.<\/p>\n

With the FC-100DZ, the illuminance decreases starting from the APS-C area but remains at approximately 93 % at the edge of the full-frame area. The RMS spot diameter is 4.8 \u00b5m on-axis and 7.2 \u00b5m at the edge of the full-frame sensor. The FC-100DF retains a slight chromatic halo from the lens, despite the correction of stellar images across the field and a brightness of nearly 90 % at the edge of the full-frame area.<\/p>\n

Prepare a complete montage<\/h3>\n

The corrector has two M72 male threads with a 1-mm pitch. It is used with a separate CO ring: CO 114D for the FCT-114DF, FCT-114DS, and FC-100DZ; CO 100DF for the FC-100DF. The assembly also includes the M-series camera rotator and the M72 L52 extension tube. This extension tube is included as standard equipment with the FCT-114D; it must be purchased separately for the FC-100DZ and FC-100DF. Check the parts already present on the telescope and follow the order indicated in the Takahashi diagram.<\/p>\n

For a CMOS camera, the appropriate M72-M48 or M72-M54 adapter provides a distance of 55 mm between the base of its camera-side thread and the sensor. Canon EF and Nikon F mounts use the M72 WR adapter with their DX-WR ring. Adapters and connecting rings are sold separately. The use of a filter in the designated slots is subject to Takahashi\u2019s disclaimers regarding stray light and vignetting.<\/p>\n

Technical specifications<\/h3>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Function<\/th>\nField flattening, factor 0.99x<\/td>\n<\/tr>\n
Compatible glasses<\/th>\nFCT-114DF, FCT-114DS, FC-100DZ, FC-100DF<\/td>\n<\/tr>\n
FCT-114DF \/ FCT-114DS<\/th>\n795 mm, f\/7.0<\/td>\n<\/tr>\n
FC-100DZ<\/th>\n791 mm, f\/7.9<\/td>\n<\/tr>\n
FC-100DF<\/th>\n734 mm, f\/7.3<\/td>\n<\/tr>\n
Image circle<\/th>\n55 mm<\/td>\n<\/tr>\n
Optical package<\/th>\n2 lenses in 2 groups<\/td>\n<\/tr>\n
Fittings<\/th>\nM72 \u00d7 1 male on both the eyepiece side and the camera side<\/td>\n<\/tr>\n
Dimensions<\/th>\n\u00d8 78 \u00d7 35.5 mm<\/td>\n<\/tr>\n
Mass<\/th>\n270 g<\/td>\n<\/tr>\n
CO Ring, Separate<\/th>\nCO 114D: FCT-114DF \/ FCT-114DS \/ FC-100DZ; CO 100DF: FC-100DF<\/td>\n<\/tr>\n
Bezel-side mounting<\/th>\nM camera rotator and M72 L52 extension tube shown in the system chart<\/td>\n<\/tr>\n
CMOS Print<\/th>\n55 mm from the base of the thread on the camera side of the M72-M48 or M72-M54 adapter<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Compatible glasses in the catalog<\/h3>\n