WCS & FITS#

Headers, coordinates, cropping, and reprojection helpers.

Headers#

`McfHeader`	A stateful wrapper around an `astropy.io.fits.Header`.
`as_mcfheader`	Return `header` as an `McfHeader` (pass-through if it already is).
`save_header`	Write a header to a portable plain-text `.hdr` file.
`load_header`	Load an `McfHeader` from a plain-text header file written by `save_header()` / `McfHeader.totextfile()`.
`force_header_2d`	A simple function to take in a header and remove items related to 3D or 4D structure -- such as NAXIS3...
`force_header_3d`	Return copy of header with all 4th-axis cards removed (NAXIS=3).
`force_header_floats`	Helper function to force various header values to floats.
`make_simple_header`	Function to make a new 'simple header' from the WCS information in the input header.
`squeeze_image`	Squeeze a FITS image to 2D, cleaning up the header to match.
`annotate_provenance_header`	Add HISTORY / COMMENT cards noting that a FITS file was created with multicolorfits (version, timestamp, optional per-layer settings).

Coordinates#

`sex2dec`	Converts sexagesimal coordinates to decimal.
`dec2sex`	Converts decimal coordinates to sexagesimal.
`deg2dms`	Convert decimal degrees to DMS components.
`dms2deg`	Convert DMS string ('dd:mm:ss.s') or [d, m, s] list to decimal degrees.
`deg2hour`	Convert decimal degrees to [hours, minutes, seconds] list.
`hour2deg`	Convert HMS string ('hh:mm:ss.s') or [h, m, s] list to decimal degrees.
`angular_distance`	Angular distance between two sky positions using the Vincenty formula.
`sky_to_pixel`	Helper function to convert sky coordinates to pixel coordinates.
`pixel_to_sky`	Helper function to convert pixel coordinates to sky coordinates.
`header_coord_grids`	Per-pixel world (lon/lat) coordinates for an image grid.
`get_cdelts`	Function to calculate CDELT1 and CDELT2 from the input header PCx_x cards.
`get_cd_matrix`	Calculate the CDn_m matrix from CDELTS and CROTA/CROTA2
`deg_per_pixel`	Calculates degrees per pixel side.
`arcsec_per_pixel`	Calculates arcseconds per pixel side.
`sterad_per_pixel`	Calculates steradians per pixel.
`beam_params_arcsec`	Returns beam parameters [BMAJ (arcsec), BMIN (arcsec), BPA (deg)] from input header
`pixels_per_beam`	Calculates the number of pixels per beam from the beam parameters (BMAJ,BMIN) in the header.

Crop & reproject#

`crop_image`	Function to crop a 2D fits image to the specified pixel bounds.
`crop_image_sky`	Function to crop a 2D fits image based on sky coordinates and specified width.
`crop_cube`	Function to crop a 3D fits cube to the specified pixel bounds.
`crop_cube_sky`	Function to crop a 3D fits cube based on sky coordinates and specified width.
`reproject_image`	Function that reprojects a 2D map from the parameters in one header to the parameters in another header.
`reproject_cube`	Reproject a 3D cube from one WCS header onto another, plane by plane.
`header_frame_name`	Determine the celestial frame of a FITS header, as an astropy frame name.
`convert_header_frame`	Build a new 2D header in a different celestial frame, covering the same sky area as the input header with the same pixel scale, with the new frame's north axis up (no rotation).
`reproject_to_frame`	Reproject a 2D image into a different celestial frame (e.g. Galactic), with the new frame's north up.
`reproject_to_galactic`	Convenience alias for reproject_to_frame(..., frame='galactic').
`optimal_common_header`	Compute an optimal common header covering a set of images, using reproject.mosaicking.find_optimal_celestial_wcs.

For long spectral cubes, reproject_cube() accepts print_progress=True (drives draw_progress_bar()). See that helper’s docstring for a tqdm alternative if you prefer wrapping the per-plane loop yourself.