Some of the reported redshifts in NED seem to show discrepancies with my estimates. Why?
A.: As with the celestial coordinates which we adopt for the objects in NED, we attempt to use the best available redshifts. However, occasional errors creep into NED, in spite of our best efforts. If you find one of these cases, please let us know so that we can fix NED and document the origin of the error. • Q.: Are the redshifts reported in NED spectroscopic or photometric? And what do the codes following the redshift mean? A.: We adopt spectroscopic redshifts whenever they are available. Sometimes, however, only a photometric redshift is available for an object, or the source of a redshift is not clearly stated in the published paper. In those cases, we flag the redshifts if we know that they are not from spectroscopy. It is still possible, however, for photometric redshifts to slip in unflagged. In cases of doubt, we urge you to go back to the published paper to check the source of the redshifts. When we can determine from the reference the Quality of a Basic Data redshift, we att
