to_fits units

[Sulla2012]

In map.to_fit, currently the CRVALs are set via self.header["CRVAL1"] = np.radians(self.center[0]), but self.center is already in units of radians. Instead, I think this should be self.header["CRVAL1"] = np.rad2deg(self.center[0]) no match the units in the header. Same with self.header["CDELT1"]