Definition
The apparent passage of a CELESTIAL BODY across a CELESTIAL MERIDIAN. Upper or superior transit is the passage across the UPPER BRANCH of the CELESTIAL MERIDIAN. Lower or inferior transit is the passage across the LOWER BRANCH. The lower transit may take place either above the HORIZON as is the case of CIRCUMPOLAR CELESTIAL BODIES, or across that branch of the MERIDIAN lying below the observer's HORIZON. Also called TRANSIT, meridian passage, CULMINATION.