I don't know if this is the first time for me to use the ASI120mm, I had one before but sold shortly, this one was newly acquired.
First one taken with my Ranger with a reducer lens, 1245 (GMT+8):-
Second one with a 3x barlows, 2 frames mosaic... uneven illumination, long time no practice, taken at 1253 and 1255 (GMT+8).:-
After taking the images, I found that I didn't set the gain to zero and it was set at 50% which is very high. No wonder why the result image is rather noisy.
I found no more Newton's ring even at 3x?