It depends on which units for Scale and Data you prefer. If you let it as shown, the Scale will be displayed in units of 'Pixels' and the Data will be displayed in units of 'Data Nummbers'.
1) If you want to have Scale displayed in units of arcseconds per pixel you have to input the correct 'Subframe scale' into the first input field and change the 'Scale unit' to 'Arcseconds'.
The 'Subframe scale' is dependent on the pixel dimensions AND the focal length of your scope.
Subframe scale (in arcseconds per pixel) = p * 206265 / fl
(p = 0.0024 mm for the ASI183)
2) If you want to have the Data displayed in units of electrons per Data Number you have to input the correct conversion gain into the second input field ('Camera gain') and change the 'Data unit' to 'Electrons'.
The camera gain is adjustable in the camera driver. So it depends on the setting that you used for capturing the data.
https://astronomy-imaging-camera.com/product/asi183mc-color (second plot from top) shows conversion gain [e-/ADU] versus gain setting in the driver for your camera.
Bernd
