Hotech SCA Field Flattener

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Hotech SCA Field Flattener
Item # HT-SCA-FFT58
  • The HoTech SCA Field Flattener is high quality optics designed exclusively for refractor telescopes.
  • Brings your camera to the closest optical axis in the drawtube/visual back for the best imaging results.
  • The HoTech SCA Field Flattener eliminates drawtube/visual back sloppiness and unstable locking from thumbscrew or unified compression ring.
  • It accepts imperfections in the drawtube/visual back and prevents oscillations and dampens vibrations.
  • The HoTech SCA Field Flattener standard 2/48mm filter thread accepts a spectrum of 35mm cameras.


HoTech SCA Field Flattener

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 accomodates f5 to f8 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" SCA T-Adapter is 19mm(0.75") and 1.25" SCA T-Adapter is 18mm (0.71") 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”/48mm (M48-P0.75) filter thread. T-ring thread accepts all kinds of 35mm cameras.

It is yet another dream come true for imagers!

HoTech Product Number: SCA-FFT58

Additional Information

Additional Information

Manufacturer HOTECH
Barrel Size Thread-on
Warranty 1 Year Warranty

Customer Reviews 1 item(s)

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.
1= Houston, We Have a Problem & 5= It's Out of This World
Review by JudgeSteele / (Posted on 5/2/2014)
Included Items

Included Items

  • HoTech SCA Field Flattener
  • T-Thread adapter for 2" drawtube/visual back focuser
  • Note: Camera T-Ring not included.
Questions & Answers

Product Questions

does it cover full frame dslr?
I am imaging through an 8" RC f8 and the curvature is about 43% on my KAF-8300 and more on my APS-C sensor. Would this get rid of most or all of the curvature for my RC and is the camera side m42 or m48 with a t-ring adapter? Thank you!
Would this work well on an Orion 6" RC f9 ?
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