6.10. clean

Cleans (Cosmic) the FITS files.

im clean

usage

im clean [-h] [–sigclip SIGCLIP] [–sigfrac SIGFRAC] [–objlim OBJLIM] [–gain GAIN] [–readnoise READNOISE] [–satlevel SATLEVEL] [–niter NITER] [–sepmed] [–cleantype CLEANTYPE] [–fsmode FSMODE] [–psfmodel PSFMODEL] [–psffwhm PSFFWHM] [–psfsize PSFSIZE] [–psfbeta PSFBETA] [–gain-apply] file output

positional arguments

file A file path or pattern (e.g., “*.fits”)

output Output directory

options

-h, --help show this help message and exit

--sigclip SIGCLIP Laplacian-to-noise limit for cosmic ray detection. Lower values will flag more pixels as cosmic rays.

--sigfrac SIGFRAC Fractional detection limit for neighboring pixels. For cosmic ray neighbor pixels, a Laplacian-to-noise detection limit of sigfrac * sigclip will be used.

--objlim OBJLIM Minimum contrast between Laplacian image and the fine structure image. Increase this value if cores of bright stars are flagged as cosmic rays.

--gain GAIN Gain of the image (electrons / ADU). We always need to work in electrons for cosmic ray detection.

--readnoise READNOISE Read noise of the image (electrons). Used to generate the noise model of the image.

--satlevel SATLEVEL Saturation level of the image (electrons). This value is used to detect saturated stars and pixels at or above this level are added to the mask.

--niter NITER Number of iterations of the LA Cosmic algorithm to perform.

--sepmed Use the separable median filter instead of the full median filter. The separable median is not identical to the full median filter, but they are approximately the same, the separable median filter is significantly faster, and still detects cosmic rays well. Note, this is a performance feature, and not part of the original L.A. Cosmic.

--cleantype CLEANTYPE Set which clean algorithm is used. “median”: An unmasked 5x5 median filter. “medmask”: A masked 5x5 median filter. “meanmask”: A masked 5x5 mean filter. “idw”: A masked 5x5 inverse distance weighted interpolation.

--fsmode FSMODE Method to build the fine structure image. “median”: Use the median filter in the standard LA Cosmic algorithm. “convolve”: Convolve the image with the psf kernel to calculate the fine structure image.

--psfmodel PSFMODEL Model to use to generate the psf kernel if fsmode == ‘convolve’ and psfk is None. The current choices are Gaussian and Moffat profiles. “gauss” and “moffat” produce circular PSF kernels. The “gaussx” and “gaussy” produce Gaussian kernels in the x and y directions respectively.

--psffwhm PSFFWHM Full Width Half Maximum of the PSF to use to generate the kernel.

--psfsize PSFSIZE ize of the kernel to calculate. Returned kernel will have size psfsize x psfsize. psfsize should be odd.

--psfbeta PSFBETA Moffat beta parameter. Only used if fsmode==”convolve” and psfmodel==”moffat”

--gain-apply If True, return gain-corrected data, with correct units, otherwise do not gain-correct the data.

6.10.1. Example:

im clean /PATH/TO/FILES*.fits /PATH/TO/DIRECTORY