Resulting cube images of channels 1 to 4 with subchannels A to C after dither subtraction. The wavelengths are chosen such that they refer to the detector image with the highest flux at the source in each band. The red circle shows the aperture for the flux extraction of the spectrum at one FWHM of the PSF of the source. The blue circle refers to three times the FWHM on which nine black circles of one FWHM are placed. We extract the flux from each circle and measure the variability to obtain an error that includes the noise in the background, σ_emp.