def get_pixel_coordinates(self, point, ccdnum):
        """
        Retrieves the pixel location of a point within the current HDUList given the
        location in the original FITS image.  This takes into account that
        the image may be a cutout of a larger original.

        Args:
          point: tuple(float, float)
            (x, y) in original.

        Returns:
          (x, y) pixel in this image.
          @param extno: the extno from the original Mosaic that the x/y coordinates are from.
        """
        hdulist_index = self.get_hdulist_idx(ccdnum)
        if isinstance(point[0], Quantity) and isinstance(point[1], Quantity):
            pix_point = point[0].value, point[1].value
        else:
            pix_point = point
        if self.reading.inverted:
            pix_point = self.reading.obs.naxis1 - pix_point[0] +1 , self.reading.obs.naxis2 - pix_point[1] + 1

        (x, y) = self.hdulist[hdulist_index].converter.convert(pix_point)
        return x, y, hdulist_index