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	This example is from a stack sample around Abell1656Abell 1656 matched to SDSS and coloured by SDSS classification (red - stars; black - galaxies). A cut in iPSFMag-iKronMag of 0.05 (shown) does a reasonable job of separating stars and galaxies.

You can calculate this using data from the MeanObject, StackObjectThin or ForcedMeanObject tables. You might improve the separation by combining results from more than one band or using a more sophisticated cut. Note that we do not expect PSF-Kron to be exactly 0.0 for stars, as Kron magnitudes by definition require a correction to take them to total magnitudes.

Faintward of i ~21 this simple cut becomes unreliable (usually over-predicts the number of stars). Also be aware that once stars become saturated (brighter than i ~14 in this example) they shift to the galaxy side of the cut. A full discussion of this method applied to Pan-STARRS data can be found in Farrow et al. (2014).