Hotech SCA Field FlattenerThe 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 telescope. 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 is shifted when the inserting device is locked in by 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
|Warranty||1 Year Warranty|
price scared me
Low price? can't be good!? I have a 229.00 one that isn't near as nice as this one. This is my favorite. What I really like is it's a FF but not a reducer. I'm using it with a 6" refractor. (F8) and a friend with a 127mm refractor recommended it. My stars are TACK sharp corner to corner. (not so with the other famous brand .8 FF reducer).
I had high expectations from this flattener. It did make the field flat but the optic I recieved was quite dirty evidently reight out of the box. The flattener resides in the light path at just the right place so that even the smallest particle of dust shows up a a huge mote in the light frames. I counted over 18 motes in my subs! Very dissapointed. This thing is impossible to clean also. The optics lie deep in the SCA section and cannot be reached to clean.
Very clever design
This flattener works great on my Astro-Tech AT111-EDT (f7). I have always had a problem with centering the camera in the 2" focuser compression fitting. The design of this flattener insures that al of the "slop" in the focuser is taken up and the imaging train is then centered perfectly, every time. The flattening effect is absolutely superb and appears to be well-matched to my refractor. I get nice, rounds stars across the entire KAF-8300 chip of my camera.