Thursday, April 7, 2016
29 Feb 1504 Lunar Eclipse
Christopher Columbus may have had a copy of Regiomontanus' Ephemerides with him in 1504 when he predicted the lunar eclipse for the natives in Jamaica to get them to continue with their provisions while he and his crew were shipwrecked. The Wikipedia article on the eclipse asserts that he had an almanac by the Portuguese astronomer Abraham Zacuto and in another place that he had Regiomontanus' Calendarium. With the rivalry between Portugal and Spain at the time it is unlikely that they would be sharing information concerning navigation. The information in the Calendarium is less detailed than that in the Ephemeris and the position given for the Sun differs somewhat. The first three columns of the Calendarium contain the day of the month, a letter indicating the day of the week and a column with days as designated in a Roman calendar. The table of regions for the Ephemeris and Calendarium both indicate a 0h 0m offset for Nuremberg so that may be the meridian that was used.