shifted-input-psf-CAMERA-EXPID.fits
- Summary:
PSF (point spread function) files model the mapping of fibers and wavelengths to pixels on spectrograph CCDs.
- Naming Convention:
shifted-inputpsf-CAMERA-EXPID.fits
, whereCAMERA
is e.g., “b0”, “r5”, etc. andEXPID
is 8-digit exposure number.- Regex:
shifted-input-psf-[brz][0-9]-[0-9]{8}\.fits
- File Type:
FITS, 998 KB
See psfnight-CAMERA-NIGHT documentation for a description of the PSF file content.
Four different PSF files are written per camera for each arc lamp exposure:
shifted-input-psf-CAMERA-EXPID.fits
: Input PSF with spectral trace coordinates and wavelength calibration adjusted to the current CCD image, used as a starting guess for the PSF shape fit.fit-psf-before-listed-fix-CAMERA-EXPID.fits: Result of the specex PSF fit before adjusting the PSF model of problematic fibers not included in the fit.
fit-psf-fixed-listed-CAMERA-EXPID.fits: Result of the specex PSF fit with the PSF model of problematic fibers interpolated from neighboring fibers.
fit-psf-CAMERA-EXPID.fits: Final PSF fit (which is the same as fit-psf-fixed-listed-CAMERA-EXPID.fits if there are problematic fibers)
The fit-psf-*.fits
files from individual exposures are combined into the
psfnight files for each night.
Flat and science exposures have a single PSF file per camera:
psf-CAMERA-EXPID.fits: psfnight file with spectral trace coordinates and wavelength solution adjusted to match this exposure. Flat exposures are adjusted only in x (cross dispersion = fiber direction), while science exposures are adjusted in both x and y (wavelength direction).