Normalization
Warning
If one of these items is selected, a normalization process will be applied to all input images before stacking.
Normalization matches the mean background of all input images, then, the normalization is processed by multiplication or addition.
Keep in mind that both processes generally lead to similar results but multiplicative normalization is preferred for image which will be used for multiplication or division as flat field.
Scale matches dispersion by weighting all input images.
This tends to improve the signal-to-noise ratio and therefore this is the option used by default with the additive normalization.
Tip
The offset and dark masters should not be processed with normalization.
However, multiplicative normalization must be used with flat-field frames.
Possible values⚓
No normalization
Additive
Multiplicative
Additive with scaling
Multiplicative with scaling