My APO and EQ mount rig had been shelved for so long. And for the first time, they performed under a dark sky.
However, the mount is now malfunctioning -- the USB port is dead and it cannot talk to the computer -- means no guiding, no easy PA. Other than that, it works smoothly. Hence, I only did 30s exposures -- and due to poor PA a lot of exposures have to be discarded. Anyway, I found new love with my scope.
And my new Sigma 20mmF1.4 DG DN is superb. Gone are those poor stars in the corners. (Well, that is true for the lens on Sony a7IV. The astro-modified Sony a7RII being used for the following picture is a different story. It suffers mild coma aberrations (but still way better than my Rokinon 20mmF1.8) due to apparently some misalignment.