Clear, no moon, no wind, 12 degrees C
Low clouds, no moon, no wind, 10 degrees C
Some initial high clouds, some wind, 85% humidity, 5 degrees C
Took some more test luminance frames on 2016-07-28, 2016-08-02 and 2016-10-03 to decide upon gain, offset and exposure time. Added RGB from previous DSLR image of same object, see http://astrophotos.se/?p=600
66x30s+17x60s+9x90s+19x120s+8x180s+26x240s+3x300s exposures with ASI1600MM-COOL and IDAS LPS-D1 filter used for luminance (224.5 minutes total exposure) taken with gain 77, offset 12 and gain 100, offset 17 settings of the camera cooled to -20C. 16x300s+8x240s+9x180s exposures with Canon EOS600Da used for RGB (139 minutes total exposure for RGB)
With gain 77 setting, the 120s exposures seem to be optimal (with some caveat since the sky was not fully dark). With gain 100, offset 17 I could not see any difference in amount and detail of nebulosity and stars when stacking 23 30s exposures compared to 3 240s exposures apart from the 30s stack had less noise and less saturated stars. This suggests that 30s exposures could be used.
On 2016-07-15 I received the new ASI1600MM-COOL camera to supplement (and in the future replace) my Canon 600Da modded DSLR. I intend to use it for acquiring luminance (and later Ha) data to be combined with RGB data acquired by DSLR. So far, I have tested it with my iMac running Parallels Desktop and Windows 10 and just finished a sequence of 100 300s darks @-20C using Sequence Generator Pro without any hiccups. I am unable to use USB2.0 connection with the camera but USB3.0 works flawlessly even with 5m cable connected with additional 5m active extension cable to the iMac. I’m using the ASCOM 6.2 platform with the ASI Camera ASCOM V184.108.40.206 driver together with SGP 220.127.116.11. Since the cooler works at around 55-75% power to get from ambient 23C to -20C. I will probably be able to work the camera at -25C or even -30C during actual night time photography. There is some little amp glow present in the darks at -15C which is almost gone at -20C. Both darks and bias frames also compares very favorably to corresponding frames from my DSLR. Will return with more information as soon as the astrophotography season begins after Aug 1st.