Data extracted from CCD frames may be accompanied by error estimates, which can be used in determining weights in the general solution. These should be in the same intensity units as the data in the SIGNAL column. The same format should be used as for the SIGNAL. The column label for estimated errors is ESTERR.
This column should not be used for ordinary photometric data (i.e., do not put estimates of ``photon noise'' here). It should only be used when an independent estimate of noise is available in addition to the information in the other columns.
If the data were expressed as magnitudes (column RAWMAG), any error estimates should also be in magnitudes.