mag += etmag mag += nom_at_ext # Can now calculate the zp array zp = refmag - mag zperr = np.sqrt(refmagerr*refmagerr + magerr*magerr) # Trim values out of zp where the zeropoint error is > 0.1 zp_trim = np.where((zperr<0.1), zp, None) zperr_trim = zperr[np.flatnonzero(zp_trim)] refmag_trim = refmag[np.flatnonzero(zp_trim)] refmagerr_trim = refmagerr[np.flatnonzero(zp_trim)] zp_trim = zp[np.flatnonzero(zp_trim)] nzp = float(ad.nominal_photometric_zeropoint()) plt.figure(1) # Plot the mag-mag plot plt.subplot(2,2,1) plt.scatter(refmag, mag) plt.errorbar(refmag, mag, xerr=refmagerr, yerr=magerr, fmt=None) plt.xlabel('Reference Magnitude') plt.ylabel('Instrumental Magnitdute') # Plot the mag - zp plot plt.subplot(2,2,2) plt.scatter(refmag, zp) plt.errorbar(refmag, zp, xerr=refmagerr, yerr=zperr, fmt=None) plt.scatter(refmag_trim, zp_trim, color='g')