it is not clear why, but the beam position on BIU2 has changed over time, even more since we checked last. it is off in both directions

we see the GATT aperture projection drifting, so it is a change in the beam transport, not in the source.

see the beam, cut by the DIAG1 slit, compared to the cross it should be centred to.

the motor encoders in the beamline have not changed since the beginning, when the beam was pointing correctly.