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 Type-90 The Type-90, also known as the MZD-2, is a Chinese submunition used in the 122 mm Type-81 cluster rocket. It is made by Norinco. Type-81 rockets with Type-90 submunitions were used by Hezbollah against Israel in the 2006 Lebanon War, and they have been used in the Syrian Civil War as bombs dropped by weaponized Hezbollah quadcopters. Each Type-90 resembles a small cylindrical bell with a ribbon at one end. A plastic band full of 3mm steel spheres wraps horizontally around the middle of the cylinder. Inside is an armor-piercing shaped charge. Each Type-81 rocket contains 39 Type-90 submunitions.