MAXI is located in the front (moving direction of ISS ) in the normal attitude of ISS. When the space shuttle docks, ISS turns back and MAXI becomes in the back side. During this period, the Horizontal camera looks back instead of looking forward. The north camera looks south. On April 7,2010, ISS turned back for Space shuttle docking. The blank region of the north camera moved to the south, around the Galactic center.
The south camera (A camera 0) is operating in lower high voltage (1550V) to expand the life time. The high voltage of other two cameras (B camera 1 and B camera 2) were also reduced. The calibration of those cameras is undergoing and the data of those cameras are excluded in the MAXI home page now. The calibration time is estimated one or two weeks.
The all-sky image taken on April 8, 2010, after the ISS turn-back. The north camera covers the south region, making a blank near the galactic center.