Aspect. Old astronomical term for a planet's position relative to another planet. Five aspects were Conjunction, Sextile (60° different), Quartile (90° different), Trine (120° different), and Opposition. The first and last aspects still remain. 2. The nearer angle between another vessel's head and the line of sight. It is expressed in degrees (0° to 180°) and qualified red or green according to whether the port or starboard side of the other vessel is visible, e.g. Green 20.