No. As you stated, if you just use the light frames without the calibration frames, the image is "noiseless."
Ergo, the noise is coming from the calibration frames or ASIStudio.
You can do partial calibration (for example use only dark frames, but not flat frames, etc) to see who the culprit is.
I assume you have taken at least as many dark frames as light frames, right? And at the same sensor temperature. Don't use fewer than 20 to 40 dark frames, in any case.
Flat frames probably don't need as many frames, since they are taken with higher illumination than the light frames. And you don't need bias frames if the dark frames are taken at the same temperature as the light frames, since the proper bias information is already embedded in the dark frames.
Chen
