Sky brightness correlation coefficients for the 16 detectors. Green triangles: J, red circles: NB118, black crosses: K_s. The x-axes show the correlation coefficient with the ambient temperature, while the y-axis shows the correlation coefficient with the sky brightness in the Y band in the given detector. The correlation coefficients on the x-axes have been multiplied by minus one, since they would otherwise be negative due to the the sky brightness being in mag/arcsec². Panel a) shows the Spearman rank order correlation coefficient r_S while panel b) shows the linear Pearson correlation coefficient r_P. The individual NB118 points are labelled with the detector number.