The Gain slider for the Main camera is in the Main Camera Settings window. The Gain slider for the Guide camera is in the Guide Settings window.
I have been guiding for almost a year now with the ASI290MM-mini, using either a Borg 36ED or Borg 50-mini as the guide scope. It has never failed me yet (RainbowAstro RST-135 mount and Takahashi EM-11 mount).
Set the gain in the Guide camera so that a few stars appear in the guide setup window when you set it to Run mode. If you don't see any stars, your gain is too low.
Select a guide star.
If the profile of the guide star is flat topped (over 255), reduce the gain of the Guide camera.
Clear the existing Guide calibration (the icon with the "i" inscribed in a circle) to start a new calibration. With the calibration cleared, clicking on the guide icon (the one that looks like a target in the column of icons on the right hand side of the Guide window) will initiate a calibration pass before the ASIAIR will start to guide. If you are familiar with the Lacerta MGEN-2 and MGEN-3, it is the same steps to take.
Set up the Calibration steps (in the Guide Settings window) so that the calibration takes between 12 and 25 steps in each North-South and East-West directions. If you are not familiar with autoguiding on the ASIAIR, I recommend that you turn Dither off (in the Telescope setup window) to reduce the learning curve.
Chen
