French astronomer, son of Greek parents, which was devoted to the observation of the planets, especially Mars and mercury. He/She worked in the homonymous Observatory next to Paris, where he/she made a series of observations with the refractor Meudon, 33 inch (81 cm), which led him to draw a map of mercury. It drew up a scale called scale Antoniadi or seeing, used to measure the quality of the conditions of observation and which uses a numbering which goes from the number I, when it is considered perfect, v, which means bad. Day is still used nomenclature that Antoniadi used in the mapping of the planets. LBD.