mark5280 Now, any exposure longer than 1 second generates a Exposure Failure.
The "1 second" appears to be the clue.
Many DSLRs and mirrorless cameras will automatically generate their own dark frames for exposures that are longer than, you guessed it, 1 second. I.e., the camera autonomously initiates a second exposure of the same duration with the shutter closed. You can actually hear the shutter if you listen carefully.
Since dark current noise is very temperature sensitive, these non-cooled cameras need to create a dark frame for every light frame that they shoot, since they cannot be assured that the sensor temperature has remained constant since the previous shot. (I have no idea why they don't include a temperature sensor; they must have a good reason, since that is what I would implement.)
As a result, a 10 second exposure will take 20 seconds to complete. A 100 second exposure will take 200 seconds to complete, etc.
There is probably a bug in ASIAIR that did not wait that extra time before the camera is done with an exposure. I.e., it may have set a timeout of 10 seconds for a 10 second exposure, but the camera needs an extra 10 seconds to create the dark frame, correcting the light frame, before returning. And causing ASIAIR to bogusly claim the camera has failed, instead of waiting the entire 20 seconds.
You can check this out by looking for some menu item in the camera that sounds something like "long exposure Noise Reduction" or "long exposure NR" and turn that function off.
Even if it now works, you are not yet out of the woods, since you cannot use the usual astrophotography "dark frames calibration" with long exposures as long as temperature is not constant for the entire imaging session (this is why you want to use a cooled camera -- not really to get lower noise, but to get consistent noise that can be calibrated out).
If turning off long exposure NR works, you can send an email to ZWO pointing the bug out to them, asking them to wait 2T+ instead of T, before declaring that there is an exposure falure.
Good luck.
Chen
