A total lunar eclipse occurred on 1 March 1504, visible at sunset for the Americas, and later over night over Europe and Africa, and near sunrise over Asia. Christopher Columbus, in an effort to induce the natives of Jamaica to continue provisioning him and his hungry men, successfully intimidated the natives by correctly predicting a total lunar eclipse for 1 March 1504, using the Ephemeris of the German astronomer Regiomontanus.
On 30 June 1503, Christopher Columbus beached his two last caravels and was stranded in Jamaica. The indigenous people of the island welcomed Columbus and his crew and fed them, but after six months, the natives halted the food supply. Columbus had on board an almanac authored by Abraham Zacuto of astronomical tables covering the years 1475–1506. Upon consulting the book, he noticed the date and the time of an upcoming lunar eclipse. He was able to use this information to his advantage. He requested a meeting for that day with the Cacique, the leader, and told him that God was angry with the local people's treatment of Columbus and his men. Columbus said God would provide a clear sign of displeasure by making the rising full Moon appear "inflamed with wrath". The lunar eclipse and the red Moon appeared on schedule, and the indigenous people were impressed and frightened. The son of Columbus, Ferdinand, wrote that the people: Columbus went into his cabin to pray and timed the eclipse with his hourglass, and shortly before the totality ended after 48 minutes, he told the frightened indigenous people that they were going to be forgiven. When the Moon started to reappear from the shadow of the Earth, he told them that God had pardoned them.
Longitude
Columbus was maybe the first to put into practice an idea proposed by Hipparchus, to use a lunar eclipse to determine one's geographical longitude. A lunar eclipse is visible across half the globe, and everyone sees it begin and end at the same moment. But the times when measured in the local solar time will differ, because everyone is in a different time zone. The local time is determined by observing the rise, culmination, or setting of the Sun. Now an almanac will predict an eclipse for some place at a certain geographical longitude at a specific local time there. The same event observed elsewhere will occur at a different clocktime. The difference in time is proportional to the difference in geographical longitude, by 15 degrees per hour. Columbus had no accurate means to determine how far he had travelled West on the globe. He observed the lunar eclipses of 15 September 1494 near Hispaniola, and that of 29 February 1504 from Jamaica. In the latter case he reported in his journal that Jamaica was 7 hours and 15 minutes from Cadiz in Spain - well on his way to China. However his site at Jamaica is actually at a longitude 4 hours 44 minutes from Cadiz. How Columbus could make such a large error of 2 hours remains puzzling, but D.W. Olson proposed a reconstruction. Columbus presumably used the Calendarium from Regiomontanus. This almanac gives the time of mid-eclipse at Nuremberg, but if Columbus erroneously interpreted the listed time as that of the beginning of the partial eclipse, then his 2h error could be explained. One can imagine that such false evidence confirmed Columbus in his belief he had reached China, overlooking the fact that he discovered an entire unknown continent.
