The HoTech SCA Field Flattener is fully multi-coated on two-element lens allowing the most efficient light transmission without sacrificing the precious collected light from your telescope. It accommodates f/5 to f/8 refractor telescopes.
You will see bright and sharp image across the entire field. To capture great images from your telescope, it is essential to position your camera firmly in and on the optical axis of your drawtube/visual back. The SCA T-Adapter center loads your camera in the drawtube/visual back with a simple threading of a compression ring forcing the built-in rubber rings outward radially, thereby centering the camera in the drawtube/visual back for optimal installation. All drawtube/visual back have manufacturing tolerances, and it requires larger diameter to accept various eyepieces and adapters. When the camera adapter is inserted, the gap between the drawtube/visual back and the inserting device became a slop problem. The rubber rings in the SCA expand radially according to users own adjustment to fill the gaps. This makes your camera seats firmly in your drawtube/visual back becoming part of your telescope for a secure and repeatable installation.
The optical axis can be shifted when the inserting device is locked in by a thumbscrew. In some cases, some poorly made unified compression ring can cause unstable tilt when locking in the drawtube due to loose tolerances between the compression ring, inner groove, and the uneven tip of the locking thumbscrew in a drawtube. The SCA T-Adapter adapts your camera without using the thumbscrew or the unified compression ring. (Note: Camera T-Ring not included.) Small imperfections inside the drawtube like dents and scratches, the rubber rings fill the gaps and faithfully centers your camera in the tube. In addition, even if the drawtube is slightly deformed in diameter, egg-shape, the rubber rings in the SCA will compensate the differences and faithfully centers your camera. Short profile design keeps the installed camera stable from low frequency oscillation transferred from the telescope in a windy environment.
The back focus of a 2-inch SCA T-Adapter is 19 mm (0.75-inch) and 1.25-inch SCA T-Adapter is 18 mm (0.71-inch) measured from drawtube shoulder to the bottom T-Thread. The all-around adjustable tightness rubber contact damps unwanted vibrations from the telescope provides you a sturdy attachment on your telescope for a stable image capture.
SCA Field Flattener has built-in standard 2/48 mm (M48 x 0.75) filter thread. T-ring thread accepts all kinds of 35 mm cameras. It is yet another dream come true for imagers! HoTech Product Number: SCA-FFT58