• pericenter (position with the closest approach to Mars)

The two graphs show the relation between altitude and camera resolution. With increasing height above Mars the observed area for the camera increases and the size of a pixel grows - the resolution decreases. This means, the resolution is increasing with decreasing altitude. At an altitude of 280 km the width of a pixel amounts to 11.2 m (HRSC) and at an altitude of 454 km it amounts to 18.1 m. To maintain the quadratic shape of a pixel, the integration time is being adapted. The true anomaly gives the position of the probe at the elliptical orbit. The pericenter is 0° and the apocenter is at 180°.