Data Reduction Frequently Asked Questions
My data have spatially variable sky background - how can I subtract it properly?
There is no way to subtract such sky background properly within the X-shooter pipeline. All processing strategies rely on a spatially constant sky background. The best way is to process the data as STARE (see http://www.eso.org/sci/data-processing/faq/can-i-process-offset-or-nodding-mode-data-as-stare-mode-data.html) without sky subtraction and then use independent software tools to fit and subtract the sky from the rectified, wavelength calibrated 2-dimensional frame (MERGE2D).