A zero-second exposure will contain only read-noise and ~half of pixels within this Gaussian distribution centred around zero count will always contain negative flux. To avoid negative counts an offset bias voltage is applied at the amplifier stage so that even when no photons are detected the A/D converter will always register a positive value. This bias-voltage offset must be accounted for in the data reduction process.
The purpose of the soxs_mbias recipe is to provide a master-bias frame that can be subtracted from science/calibration frames to remove the contribution of pixel counts resulting from the bias-voltage.
| Data Type | Content | Related OB |
|---|---|---|
| FITS images | raw bias frames (UV-VIS/AC exposures with exptime = 0) | SOXS_img_cal_Bias, SOXS_gen_cal_VISBias |
| Parameter | Description | Type | Entry Point | Related Util |
|---|---|---|---|---|
| frame-clipping-sigma | number of σ from the median frame flux beyond which pixel is added to the bad-pixel mask | float | settings file | clip_and_stack |
| clipping-iteration-count | number of sigma-clipping iterations to perform when added pixels to the bad-pixel mask | int | settings file | clip_and_stack |
| stacked-clipping-sigma | number of σ deviations from the median pixel flux beyond which pixel is excluded from stack | float | settings file | clip_and_stack |
| stacked-clipping-iterations | number of σ-clipping iterations to perform before stacking | float | settings file | clip_and_stack |
The purpose of the soxs_mbias recipe is to stack raw bias-frames together (using the clip_and_stack utility) into master-bias frames and in the process clipping rogue pixels from the individual raw frames and reducing the read-noise contribution.
| Data Type | Content |
|---|---|
| FITS image | Master bias frame (frame containing typical bias-voltage applied to the detector) |
| Metric | Description |
|---|---|
| TBC | ... |
.. autoclass:: soxspipe.recipes.soxs_mbias
:members: