make_tweakreg_catalog

jwst.tweakreg.tweakreg_catalog.make_tweakreg_catalog(model, snr_threshold, kernel_fwhm, bkg_boxsize=400, coverage_mask=None, starfinder_name='iraf', starfinder_kwargs=None)[source]

Create a catalog of point-line sources to be used for image alignment in tweakreg.

Parameters:

  • model (ImageModel) – The input ImageModel of a single image. The input image is assumed to be background subtracted.

  • snr_threshold (float) – The signal-to-noise ratio per pixel above the background for which to consider a pixel as possibly being part of a source.

  • kernel_fwhm (float) – The full-width at half-maximum (FWHM) of the Gaussian kernel used to convolve the image.

  • bkg_boxsize (float, optional) – The background mesh box size in pixels.

  • coverage_mask (array_like (bool), optional) – A boolean mask with the same shape as model.data, where a True value indicates the corresponding element of model.data is masked. Masked pixels will not be included in any source.

  • starfinder_name (str, optional) – The photutils star finder to use. Options are ‘dao’, ‘iraf’, or ‘segmentation’. - ‘dao’: photutils.detection.DAOStarFinder - ‘iraf’: photutils.detection.IRAFStarFinder - ‘segmentation’: photutils.segmentation.SourceFinder

  • starfinder_kwargs (dict, optional) – Additional keyword arguments to be passed to the star finder. for ‘segmentation’, these can be kwargs to photutils.segmentation.SourceFinder and/or photutils.segmentation.SourceCatalog. for ‘dao’ or ‘iraf’, these are kwargs to photutils.detection.DAOStarFinder or photutils.detection.IRAFStarFinder, respectively. Defaults are as stated in the docstrings of those functions unless noted here: - ‘dao’: fwhm=2.5 - ‘iraf’: fwhm=2.5 - ‘segmentation’: npixels=10, progress_bar=False

Returns:

  • catalog (Table) – An astropy Table containing the source catalog.

  • segmentation_image (ndarray or None) – The segmentation image, or None if not applicable.