Data Reduction Frequently Asked Questions

What is the best way to reduce UVB/VIS NODDING data?


For UVB and VIS data the sky background is much lower than for NIR data. Therefore the subtraction of the NODDING frames from each other may add unnecessary noise to the target's spectrum. If the sky background is comparable or lower than the target's flux you will usually get better results if you reduce the NODDING data with the xsh_scired_slit_stare recipe. This recipe fits the sky background and therefore does not introduce additional noise with the sky correction.

To do so with the Reflex workflow use for the DataOrganiser the OCA file xsh_wkf_stare.oca instead of the default one xsh_wkf.oca. This is done by right-clicking on the DataOrganiser, selecting Configure Actor, replacing the name of the OCA file in the first line of the pop-up window and clicking on Commit. This change will result in the pipeline processing the data individually with the xsh_scired_slit_stare recipe.

Please note that the default parameters for xsh_scired_slit_stare assume that the object is positioned at the center of the slit, which usually not true for NODDING data. So you may have to adjust the extraction parameters accordingly.