LO Doppler Tracking Issue March 13 - May 25, 2023

It was noticed recently that data taken with the GBT during the period 13th
of March - 6 pm (ET) 25th of May 2023 were being incorrectly corrected for
Doppler tracking in barycentric/LSR frames. The main issue has now been fixed,
although data taken during that period have almost certainly been incorrectly
adjusted for the motion of the Earth/Solar system. We are working on a fix to
retroactively repair these data. If you observed using the topocentric frame
for your data (i.e. vframe='topo' in your configuration), then you do not need
to be concerned about this issue. However, for any other frame, please wait for
us to contact you again before using your data for any publications or general
analysis.