Hotech 2" SCA Field Flattener

SCA Field Flattener 2"

The image plane of most refractor telescopes is not flat, but camera sensors are. This makes it impossible to get an evenly sharp image over the whole field. Slight differences of instruments with long focal lengths cannot be seen if the photograph was made on film, but these instruments are barely used today. With modern telescopes and modern cameras, it becomes necessary to flatten the image plane.

The SCA Field Flattener is designed for this purpose. It is suitable for refractor telescopes with focal ratios from 1:8 to 1:5 and, if the optics itself is good, you will see bright and sharp image across the entire field.

Many flatteners will change the focal length of the system, but with this one from Hotech, it will stay the same.

The Self-Centering Adapter (SCA) mechanism provides repeatable and reliable connection between your telescope and the camera.

The SCA T-Adapter fits any telescope that uses a 2” focuser or visual back. Use your existing T-Ring that matches your brand of camera and thread onto the SCA T-Adapter.

SCA brings your camera to the closest optical axis in the drawtube/visual back for BEST imaging result

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.

SCA eliminates drawtube/visual back jiggle

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 becomes a jiggle 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.

SCA eliminates unstable locking from thumbscrew or unified compression ring

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.

SCA accepts the imperfection of a drawtube/visual back

Small imperfection 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.

Question:
How do you have to measure the working distance?

Answer from Teleskop-Service:
The working distance is measured from the beginning of the connection thread on the housing of the corrector (see example picture):

Safety informations: PDF Download