Class SIP

x.__init__(...) initializes x; see x.__class__.__doc__ for signature

Parameters:

• header (PyFITS header object or string) - A PyFITS header object or a string containing the raw FITS header data.
• relax (bool) - Degree of permissiveness:
  • False: Recognize only FITS keywords defined by the published WCS standard.
  • True: Admit all recognized informal extensions of the WCS standard.

Raises:

• MemoryError - Memory allocation failed.
• ValueError - Invalid key.
• ValueError - Header does not contain SIP information.
• KeyError - Key not found in FITS header.

Overrides: object.__init__

(inherited documentation)

Convert focal plane coordinates to pixel coordinates.

Pixel coordinates are zero-based.

Parameters:

• x (array of double) - Array of y focal plane coordinates, or if y is not provided, a 2-dimensional array of both x- and y-coordinates.
• y (array of double or None) - Array of y focal plane coordinates. If provided, x must be 1-dimensional and the same length as y.

Returns:

If both x and {y} were provided, a 2-tuple of arrays, where the first element is u pixel coordinates and the second element is v pixel coordinates. Otherwise, a single 2D array containing both u and v.

Raises:

• AssertionError - len(x) == len(y)

Convert pixel coordinates to focal plane coordinates.

Pixel coordinates are zero-based.

Parameters:

• u (array of double) - Array of u pixel coordinates, or if v is not provided, a 2-dimensional array of both u- and v-coordinates.
• v (array of double or None) - Array of v pixel coordinates. If provided, u must be 1-dimensional and the same length as v.

Returns:

If both u and {v} were provided, a 2-tuple of arrays, where the first element is x focal plane coordinates and the second element is y focal plane coordinates. Otherwise, a single 2D array containing both x and y.

Raises:

• AssertionError - len(u) == len(v)