Phase angle (astronomy) less than 90° represent backscattering; values greater than 90° represent forward scattering. For some objects, such as the Moon (see lunar phases), Venus and Mercury the phase angle (as seen from the Earth) covers the full 0–180° range. The superior planets cover shorter ranges. For example, for Mars the maximum phase angle is about 45°. The brightness of an object is a function of the phase angle, which is generally smooth, except for the so-called opposition spike near 0°, which does not affect gas giants or bodies with pronounced atmospheres, and when the object becomes fainter as the angle approaches
Type 90 AFV rear; the latter open outwards. In each side of the hull there are three firing ports with periscopes. On either side of the forward hull, a cluster of four 76 mm smoke grenade dischargers is mounted. The vehicle is fully amphibious, a folding trim board stowed at the front of the hull needs to be raised, and the vehicle can then propel itself in the water using its tracks. Standard equipment includes an NBC system, a Type 889 radio, and a Type 803 intercom system. Type 90 AFV The Type 90 is an armoured fighting vehicle produced by Chinese company