This image was acquired during the final testing stages of my new OTA, designed and recently built by Roland Christen from Astro-Physics. It is an 167 mm, f7.2, fluorite triplet apochromat, built from a chunck of fluorite originated at Zeiss's APQ optical shop before it was shut down. Hence, I decided to call it an AP167 FLZ! It is a beautiful instrument, based on the same mechanics of the latter AP175 series, 4" focuser and all.
The image was acquired by Roland on 10/14/2016 (and processed by me), using an STL11000 (LRGB 100:20:20:20) during the testing phase of a custom made flattener (that was uncoated at the time), under an almost full moon. So less than optimal, finished conditions, thus the "semi" prefix in the title.
For a high resolution version click
here
