Taken on the early evening of May 14, 2019 during a brief period of partly cloudy skies before the "May Gray" overcast returned to completely cover the night skies. If you are lucky at this time of the year (in San Diego county) to have even thirty minutes of clear skies after sundown then the seeing conditions can be surprisingly good as the thick marine layer brings both low clouds and stable seeing.
This was acquired with SharpCap and processed with AutoStakkert! (best 20% of about 1800 frames, although about one third of those were lost to clouds), wavelet sharpened with Registax, and final tweaks with Photoshop CC2019. Taken with a Celestron C6 (at f/10), a ZWO ASI178MM-Cool camera, and a Baader 610nm Long Pass Filter. I would have liked to have tried a different filter (green, perhaps even blue) to take advantage of the good seeing, but the clouds arrived less than twenty minutes after I started the session. That said, this is probably the highest resolution image of Clavius that I've gotten with the C6.
The smallest crater (on the eastern edge of Clavius) that I would consider being clearly resolved is just about 1.6km in diameter, representing just under one arc second (0.93") at the then distance to the moon. However, given the foreshortening caused by the far southern location of Clavius this calculation probably underestimates the actual resolution of the image.
Edited by james7ca, 16 May 2019 - 02:42 AM.