Table summarizes the results of the multiple classifiers described above. However, these numbers were also not very satisfactory to the astronomers. The features magnitude, sharpness and chisquare appear very powerful. Magnitude has an almost linear relation with the catalog magnitude of the objects in the simulated SDSS, as shown in Fig. . So it provides a better basis for brightness cutoffs than either peak intensity or peaksig .
Sharpness estimates the intrinsic angular size of the measured object outside the atmosphere.
It should have values close to zero for single stars, large positive values for blended doubles and partially resolved galaxies, and large negative values for cosmic rays and blemishes. Hence it can be used to divide objects into brightness ranges reliably. We will describe these experiments next.