Note that most of this article has been revised heavily, because I recently discovered that most of the gradient problems with circular rings were actually caused by Nikon and their alterations to the RAW data. However, not all of the gradients were solvable with those considerations, and because I don’t have this focal reducer anymore to test with, I’ll only state what I can.
The Antares f/6.3 Focal Reducer for Schmidt-Cassegrain Telescopes is a low-price option for reducing the focal length of your Schmidt-Cassegrain telescope from f/10 to f/6.3. This “speeds up” the optical train by reducing the focal length and magnification of the scope, requiring less time to integrate the same signal. A focal reducer along this line is probably the most common accessory bought for SCTs because for beginners Continue reading “Antares f/6.3 Focal Reducer for SCTs”