Hi Alain There is a subtile difference between "meridian transit" and "culmination". The first term means the point and the instant where and when the diurnal path of a celestial body crosses the meridian of an observer. The second one indicates the moment (and the point in the celestial sphere) of the higher altitude reached by the body in its diurnal path. If the celestial body has a fixed, invariable declination "transit" and "culmination" occur in the same time and the altitude is the maximum the body can reach. For bodies whose declination is variable (specifically the Sun and the Moon, but in effects also "fixed stars" and generally all celestial bodies have very very small variations) the two moments are slightly different and different are the corresponding astronomical altitudes and azimuths. For normal persons fond of Astronomy the question is irrelevant, but not for Astronomers and (sometimes) for Seamen too. Before the "GPS hera" when sailors used sextants and stars for fixing their position at sea (a few years ago), in some exceptional occurrences, they had to distinguish between transit and culmination about the Sun to get more precision in Latitude determination. The difference was determined not only by the variable declination of the body but also by the speed and the course followed by the ship. This is in theory. Actually I think that a very few sailors paid attention to distinguish the two moments, due to the small difference resulting.
Best regards F.Martinelli ------------------------------------------------------ Nautical CollegeARTIGLIO Viareggio (Italy) http://www.nauticoartiglio.lu.it [EMAIL PROTECTED] Lat 43.8N Long 10.2 E ------------------------------------------------------
