frb.figures.finder

Module for generating a finder chart

frb.figures.finder.from_hdu(hdu, title, **kwargs)[source]

Convenience function to handle an HDU to generate a finder chart

see generate() for more details

Args:

  • hdul (astropy.io.fits.PrimaryHDU)

  • title (str)

Returns:

figure generated

Return type:

matplotlib.pyplot.figure, matplotlib.pyplot.Axis

frb.figures.finder.generate(image, wcs, title, flip_ra=False, flip_dec=False, log_stretch=False, cutout=None, primary_coord=None, secondary_coord=None, secondary_offset: bool = True, third_coord=None, slit=None, vmnx=None, extra_text=None, outfile=None, figsize=None)[source]

Basic method to generate a Finder chart figure

Args:

  • image (np.ndarray) – Image for the finder

  • wcs (astropy.wcs.WCS) – WCS solution

  • title (str) – Title; typically the name of the primary source

  • flip_ra (bool, default False) – Flip the RA (x-axis). Useful for southern hemisphere finders.

  • flip_dec (bool, default False) – Flip the Dec (y-axis). Useful for southern hemisphere finders.

  • log_stretch (bool, optional) – Use a log stretch for the image display

  • cutout (tuple, optional) – SkyCoord (center coordinate) and Quantity (image angular size) for a cutout from the input image.

  • primary_coord (astropy.coordinates.SkyCoord, optional) – If provided, place a mark in red at this coordinate

  • secondary_coord (astropy.coordinates.SkyCoord, optional) – If provided, place a mark in cyan at this coordinate It is assumeed this is for an offset star (i.e. calculate offsets) unless secondary_offset = False

  • secondary_offset (bool, optional) – If True, the secondary_coord provide is for an offset star Otherwise, secondary_coord is considered the second of a pair of scientific sources

  • third_coord (astropy.coordinates.SkyCoord, optional) – If provided, place a mark in yellow at this coordinate

  • slit (tuple, optional) – If provided, places a rectangular slit with specified coordinates, width, length, and position angle on image (from North to East) [SkyCoords(‘21h44m25.255s’,-40d54m00.1s’, frame=’icrs’), 1*u.arcsec, 10*u.arcsec, 20*u.deg]

  • vmnx (tuple, optional) – Used for scaling the image. Otherwise, the image is analyzed for these values.

  • extra_text – str Extra text to be added at the bottom of the Figure. e.g. DSS r-filter

  • outfile (str, optional) – Filename for the figure. File type will be according to the extension

  • figsize (tuple, optional) – tuple to define the figure size. It goes within the fig=plt.figure(figsize=figsize)

Returns:

matplotlib.pyplot.figure, matplotlib.pyplot.Axis

frb.figures.finder.sdss_dss(coord, title, show_circ=True, EPOCH=None, imsize=<Quantity 5. arcmin>, outfile=None, show_slit=None, show_another=None, cradius=None, in_img=None, dss_only=False, vmnx=(None, None))[source]

Generate a SDSS or DSS finder

Pulled from xastropy

Args:

  • coord (SkyCoord)

  • title (str)

  • show_circ (bool, optional) – Show a yellow circle on the target

  • EPOCH (float, optional) – Defaults to 2000.

  • imsize (Quantity or Angle) – Size of the finder

  • show_slit (list, optional) – Show a slit with [width, length, PA]

  • show_another (bool, optional) – Not yet functional

  • cradius (Quantity, optional) – Circle radius, only shown if show_circ is True. Default is imsize/50.

  • in_img (PIL image, optional)

  • dss_only (bool, optional) – Only pull from DSS

  • vmnx (tuple, optional) – vmin, vmax

frb.figures.finder.getjpg(coord, imsize, dss_only=False)[source]

Grab an SDSS or DSS image

Args:

  • coord (SkyCoord)

  • imsize (Angle or Quantity) – image size

  • dss_only (bool, optional) – Only pull from DSS

Returns:

Image, flag indicating if the image is B&W

Return type:

PIL, bool

frb.figures.finder.dsshttp(coord, imsize)[source]

Generate URL for DSS

Args:

  • coord (SkyCoord)

  • imsize (Angle or Quantity) – image size

Returns:

URL

Return type:

str

Note

Finder-chart workflows may require optional imaging dependencies such as photutils and scikit-image in your environment.