The Telescope Authority
Since 1947

View Shopping Cart

Your Cart is Empty

Hotech SCA Field Flattener


- Read
  • One Left in Stock

Add to Wishlist

Got questions? Click for live chat

Product Details

  • 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

  • specifications

    Warranty1 Year Warranty

Product Reviews

Customer Reviews
4.7 Based on 6 Reviews
5 ★
4 ★
3 ★
2 ★
1 ★
Customer Photos
Write a Review Ask a Question

Thank you for submitting a review!

Your input is very much appreciated. Share it with your friends so they can enjoy it too!

Filter Reviews:
    United States United States

    Do not use it on the Z61, it will not work!

    I should have been patient and waited until Opt got more dedicated field flatteners for their Williams Optics Z61 telescopes, because this field flattener will not work with the Z61. I tried it with 3 different cameras and tried it with and without spacer adapters. It claims to be directly screw it into the T ring , but that is as good as not even having it, because the stars continue to be elongated, like they are falling towards the center of the view. Adding 10 mm spacer ring helped, then adding more looked like helped more, then my focuser was all the way ******* in and couldn't find focus. So the 55mm (space between flattener glass and sensor) became 65mm then 75mm, each extra 10mm spacer ring helped more, but eventually didn't flatten much. As it turns out, Williams Optics is being clever with their cheap telescopes and their $450 61mm telescope is really $700, because you will need to buy their $220 field flattener directly designed (and probably cannot be used for other) for their telescope. Very Apple-ish move, if you ask me. The picture shows the upper right corner with the recommended 55mm spacing (canon 60D) directly ******* into the Camera's T ring. Extra ring spacer-adapters (another $30) marginally help but not enough to look substantially different.

    OPT Telescopes Hotech SCA Field Flattener Review
    Richard H.
    United States United States

    Hotech is #1...

    ...for my field flattener for my Explore Scientific 127mm FCD100 CF APO. I have two other flatteners including the ES designed for the 127mm and the Hotech beats them both hands down for flattening the field from corner to corner. Thanks to a well known YouTube astrophotographer I purchased this piece of glass not knowing what to expect. I was pleasantly surprised after using it for two nights. After reviewing my raw data the field was flat with round stars across the entire image corner to corner/edge to edge. Well worth the purchase.

    A OPT Telescopes Customer
    Kevin W.
    United States United States

    Sharp star points - edge to edge

    My primary purpose in purchasing this flattener was to reach the little extra back-focus needed on my ES ED102 that the 2 extender tubes didn't quite provide. In short, it solved my back-focus issue, provided a more stable image train connection to my focuser, with the added bonus of an exceptionally flat/sharp image edge to edge, all at an economical price.

    Jeffrey S.
    United States United States

    Quality Field Flattener

    Works perfectly. Removes 100% of all field flattening issues from imagery. Completely satisfied

    Ron K.

    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).


    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.