The technique was developped by several persons, including A. de Bonnevie, E. Kraaikamp and others while Sam Wen encouraged us to try planetary techniques on deep-sky objects with the early prototype of ASI224.
The 224 is the best for that, thanks to its extremely low readout noise.
One-second exposure seems to be the limit to get rid of a great part of turbulence.
Once the exposure has been set, adjust the gain. Try to pick up a moderate gain even if the histogram is only 30% full. Tests performed with 100, 250 and 500ms gave no better results because the gain became excessive to compensate for the lack of contrast, and increasing gain does not increase the incoming light while turbulence did not noticeably diminish.
It's better to get more images with less gain, at the price of loooong stacking.
You will get perfect pictures by taking dark frames (with SharCap or FireCapture you can take some tens of dark frames then the software subtracts them while acquiring the frames).
Nicolas
