def get_pixel_skydirs(self):
        """Get a list of sky coordinates for the centers of every pixel.

        """

        xpix = np.linspace(0, self.npix[0] - 1., self.npix[0])
        ypix = np.linspace(0, self.npix[1] - 1., self.npix[1])
        xypix = np.meshgrid(xpix, ypix, indexing='ij')
        return SkyCoord.from_pixel(np.ravel(xypix[0]),
                                   np.ravel(xypix[1]), self.wcs)