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
Hour angle is paired with the declination to fully specify the location of a point on the celestial sphere in the equatorial coordinate system. The local hour angle (LHA) of an object in the observer's sky is where LHA is the local hour angle of the object, LST is the local sidereal time, formula_3 is the object's right ascension, GST is Greenwich sidereal time and formula_4 is the observer's longitude (positive east from the prime meridian). These angles can be measured in time (24 hours to a circle) or in degrees (360 degrees to a circle)— one or the other, not both.