HMI Roll Maneuver Complete, Antenna Handovers Continue

On October 12 SDO successfully performed a 7-hour roll maneuver to help calibrate the HMI instrument calibration. The spacecraft roll started at same time as HGA handover operation. This complicated the operational sequences but did not stop either maneuver.

While it is easy to point a space-based instrument at the center of the Sun it is more difficult to know the precise location of the Sun's rotation axis. Data from the roll maneuvers help the scientists to understand how their instrument response varies at different angles of the rotation axis. This is then used to more accurately remove the rotation effects from the data.