Target angle submarine observer estimating target angle pictures himself on the target ship looking back at the submarine. Relative bearing of the submarine is the clockwise angle in degrees from the heading of the target ship to a straight line drawn from the target ship to the submarine. When target angle is 0° (or 360° ) the target ship is coming directly toward the submarine. Target angles between 0° and 90° indicate the target ship is moving toward and to the right of the submarine. Target angles between 90° and 180° indicate the target ship is moving to the right and away
Beta angle the beta angle of other objects. For example, the beta angle of a satellite in orbit around Mars, with respect to the Earth, defines how much of the time the satellite has a line of sight to the Earth - that is, it determines how long the Earth is shining on the satellite and how long the Earth is blocked from view. That same satellite also will have a beta angle with respect to the Sun, and in fact it has a beta angle for any celestial object one might wish to calculate one for: any satellite orbiting a body