NavList:

Well, Bedini was clearly wrong. The circumpolar motion was well known to Portuguese mariners before Columbus. The "Regimento do Norte" which explained how to find out how many degrees to add or to subtract from a measurement of the height of Polaris was most probably "invented" prior to 1475; cf.: Albuquerque, Luis de, Guía Náutico de Muníque e Guía Náutico de Evora, Lisboa 1991, 24 - 44.

The "latitude by Polaris" certainly preceded latitude by meridian altitude of the sun which was well known by the time of Columbus (although - to judge by his own writings - he himself was not good at astronomical navigation); the latter method was developed when Portuguese navigators sailing south along the African coast during the later voyages of exploration in the 15th century approached the equator and were not able to use the "Regimento do Norte" any more because Polaris was too low over the horizon.

And by the way: it is also a myth that Columbus discovered the change of declination in space.

Wolfgang
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