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 Kyū-maru to the left of the main gun. The profile of the Type 90 is similar to the German Leopard 2A4 and it uses modular ceramic and steel composite armor, common in contemporary tank designs. The adoption of modular composite armor design facilitates the upgrading and exchange of the armor, and its frontal turret armor is rated at 380mm of effective thickness against kinetic energy penetrators, while the upper frontal hull armor is rated at 320mm of effective thickness against kinetic penetrators. The Type 90 is smaller than most main battle tanks with a height of , a width of ,