  The NASA/IPAC Extragalactic Database (NED) is an impressive tool for finding
near-exhaustive information on millions of astrophysical objects. Here we
outline a small systematic error that occurs in NED because a low-redshift
approximation is used when making the correction from redshifts in the
heliocentric frame to the cosmic microwave background (CMB) rest frame. It
means that historically NED systematically misreported the values of CMB-frame
redshifts by up to $\sim10^{-3}z$ (about 0.001 at redshift of 1). While the
error is generally negligible for most applications, it is still important to
remove systematic redshift biases, as they propagate to cosmological
parameters. We have consulted with the NED team and they are updating the
software to remove this systematic error so these corrections are accurate at
all redshifts. Here we explain the changes and how they impact the redshift
values NED currently reports.
