This directory contains the calibration data files (pixel maps, darks, flats, offsets, etc) for the coronal EUV imager "SWAP" onboard the PROBA2 mission of the European Space Agency. An additional file contains the SWAP response function and addition useful instrument parameters. More detailed documentation for each of the SWAP calibration routines is available in the files themselves.

The P2SW_DRKSUB routine applies instrument observing-mode-specific ADC bias level and dark current subtraction to PROBA2/SWAP images. First, a direct subtraction of a dark FITS file (swap_biasds_yyymmdd_hhmmss.fits), scaled for detector temperature and exposure time, is performed. Note that the dark correction of images taken in CDS mode does not require this first step as the bias is intrinsically removed from images acquired in this observing mode. Second, a temperature-dependent dark-current estimate is subtracted. For this the closest-in-time dark coefficient file (swap_dark_coefs_yyyymmdd_hhmmss.save) is used, which contains the coefficients of the polynomial estimate of the dark current produced with the method explained in Halain et al. 2012 (doi:10.1007/s11207-012-0183-6). This routine also allows to instead subtract a real dark image from the data by setting the dark_form keyword to ‘fits’. In that case, the most recent dark image in the caldb is used, that is swap_darkcds_yyyymmdd_hhmmss.fits or swap_darkds_yyyymmdd_hhmmss.fits, depending on the instrument observation mode.
 
The P2SW_FFCORR function applies instrument flat-field correction to PROBA2/SWAP images, correcting for instrument defects and optical variations. The input image is divided by the closest-in-time instrument flat field, that is swap_flatcds_yyyymmdd_hhmmss.fits or swap_flatds_yyyymmdd_hhmmss.fits, depending on the instrument observation mode.

The P2SW_PIXREP function reinstates onboard cosmic ray replaced pixels and saturated pixels in PROBA2/SWAP images. It returns the input image with the missing pixels contained in the input image FITS extension replaced by their local 3x3 pixel median value. Pixels identified as saturated are replaced with 4400 using the closest-in-time saturation map correction FITS file, that is swap_satcds_yyyymmdd_hhmmss.fits or swap_satds_yyyymmdd_hhmmss.fits, depending on the instrument observation mode.

The P2SW_PMCDIV and P2SW_PMCREP functions return PROBA2/SWAP images corrected for onboard processing: P2SW_PMCDIV returns the input image with pixels identified as having undergone onboard-satellite multiplication modifications returned to their originally measured onboard values and P2SW_PMPREP returns the input image with pixels identified as having undergone onboard-satellite neighbourhood replacement again replaced by the local median. These corrections are performed using the closest-in-time pixel map correction FITS file (swap_pmc_yyyymmdd_hhmmss.fits).

The P2SW_PSFCOR function removes stray-light by deconvolving the image with an empirically determined point spread function (PSF), stored in the swap_psf_20120926_000000.save file. The PSF model used for SWAP is described in Seaton et al. 2013 (doi:10.1088/0004-637X/777/1/72). 

The swap_response_20120611_000000.save file contains the response function of SWAP expressed in DN photon^-1 cm^2 str px^-1 as a function of wavelength (nm), as well as a number of SWAP characteristics.