Re: FITS file doubles in size after preprocessing
Posted: 17 May 2019, 10:57
OK, the range is 437..68691 (it can be read on the status bar of the image too), so it exceeds the 16 bit range.
The cause is the flat field correction. This can happen if the bias of the camera is low and the vignetting is strong.
To force a 16 bit range before saving there are several ways, for example the command: Arithmetic / Clamp / Maximum.
For a scientifically correct result the flat field must also be corrected from its dark frame.
The cause is the flat field correction. This can happen if the bias of the camera is low and the vignetting is strong.
To force a 16 bit range before saving there are several ways, for example the command: Arithmetic / Clamp / Maximum.
For a scientifically correct result the flat field must also be corrected from its dark frame.