Description
ORBS is a data processing pipeline specifically developped for SpiOMM and SITELLE data cubes, written by
Thomas Martin. It consists in several broad processing steps:
- Read and detrend - bias, dark subtract and flat field correct - individual raw data images, assemble them in raw data cubes (one per camera). Idem for associated standard star images
- Realign images within each camera data cube. This corrects for guiding imperfections, as well as internal instrumental flexion
- Detect cosmic ray hits in data cubes
- Compute interferograms for both arms (cameras), from detrended and realigned images, taking into account CR hit maps.
- Compute the relative astrometry of both cameras, and transform the second camera's cube into the first camera's frame
- Merge both interferograms, taking into account the relative extinction of frames (measured with the combination of both cameras that recovers the unmodulated light) and possible stray light contamination. Compute an astrometric solution for the merged interferogram cube with SIP corrections
- Compute phase maps from the complex spectrum obtained from the merged interferogram, possibly with the help of ancillary phase data obtained from specific calibration sequences. Use these phase maps to phase-correct the raw spectral cube. A wavelength calibration map, obtained from a specific green HeNe laser spectral cube, is then used to calibrate the spectral cube in wavelength.
- Proceed with the spectrophotometric calibration of the phase-corrected spectral cube. This step uses the standard star images associated with the science data to compute an overall flux calibration coefficient. The relative spectrophotometric calibration is obtained with the help of specific standard star spectral calibration cubes.
- Export the calibrated cube in an HDF5 archive, together with the associated wavelength calibration map, and a deep image obtained from the merged interferogram. This HDF5 archive, together with a FITS version of the spectral cube and the deep image, are then archived at CADC. Note that the ORCS analysis software uses the HDF5 archive as an input, not the FITS files.
The ORBS software suite can be installed from https://github.com/thomasorb/orbs. Questions can be sent to Thomas Martin.
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