Bearings in space

[ericbsmith]

Originally Posted by William

On the local scale, just treat bearings relative to the ship. Take a line straight forward from the ship. An object is at some number of degrees port or starboard of that line (up to 180 degrees, a.k.a. 'aft' or 'dead astern'), and a number of degrees elevation, positive 90 to negative 90.

"Bogey 40 degrees to port, 20 degrees elevation" might get shortened to "Bogey, port 40 plus 20." For detail on its current relative heading, its directions of travel might be "closing", "orbiting" or "moving away," "heading to our port or starboard," and "climbing" or "diving."

The Star Trek Next Generation Tech Manual describes a system where dead ahead is 0° by 0° (000 mark 0), with the bearing continuing all the way around the ship up to 359° by 359°. Azimuth (right/left rotation) comes first then elevation/declination.

Thus a course of "24 mark 35" means 24° to the right of the current course, 35° up above it. Since the numbering continues all the way around, this means that in the azimuth 90° would be a course directly to the right, while 270° would be a course directly to the left, 180° would be directly behind. An elevation of 90° is straight up, 270° straight down, and 180° straight behind.