(1) The number of times the apparent topocentric, angular diameter of a celestial body is greater than the geocentric, angular diameter of that body.

(2) The apparent increase in diameter of a celestial body as its angular elevation increases, because the body is closer to the observer. This should not be confused with the apparent increase in size of the Moon or Sun at the horizon as compared to the size when well above the horizon. This latter phenomenon seems to be psychological rather than physical in nature.