The 1492 light sighting was a sighting of unknown light during the first voyage of Christopher Columbus on October 11, 1492, by some crew members of Santa Maria, Pinta and possibly Niña shortly before the landing on Guanahani. The light was reported in Columbus' journal, Ferdinand Columbus' Vita del Ammiraglio (The Life of the Admiral), the proceedings of the Pleitos colombinos (the long lawsuit involving the heirs of Columbus) and some other sources.
Columbus described the light as "a small wax candle that rose and lifted up, which to few seemed to be an indication of land". He received the royal reward for the sighting. His son Ferdinand also characterized it as a candle that went up and down.
Bartolomé de las Casas noted the event in his abstract of Columbus's log: "A sailor named Rodrigo de Triana saw this land first, although the Admiral, at the tenth hour of the night, while he was on the sterncastle saw a light, although it was something so faint that he did not wish to affirm that it was land. But he called Pedro Gutierrez, the steward of the king's dais, and told him that there seemed to be a light, and for him to look: and thus he did and saw it".
It was calculated that the twelve leagues that the crew had run since 10:00 p.m., with the two leagues' distance off the land, essentially correspond to the distance and location of San Salvador Island (formerly Watling's Island) from Guanahani. As such, it was presumed that the light was on San Salvador Island, which was passed by Columbus. Judging by the speed of the ships, provided in the naval journal, L. T. Gould supposed that the light "must have been some 35 miles or so eastward of the landfall, and well to windward of it".
An early explanation was offered by Bartolomé de las Casas, who wrote: "I feel about this is that the Indians at night throughout these islands, as they are temperate without any cold, go out or used to go out from their straw houses that they call bohíos at night to comply with their natural necessities and take in hand a firebrand, or small torch, or a chink of pine or of another very dry and resinous wood which burns like a torch, when it is dark night, and with which they guide themselves back again, and in the manner could be seen the light which Christopher Columbus and the others saw the light three or four times". This version was supported by Morison, despite the fact that it tended to undermine his preferred landfall at San Salvador Island. Others have advanced the hypothesis that the light might have been an Indian fishing in a canoe at night, but the very high winds imply that would have been quite unlikely.
These problems have led to the conclusion by some that the light was not on Guanahani, the island of the first landfall, but on another, more easterly island bypassed in the night.
It has been proposed that the light was caused by bioluminescent protozoa on the rocks of Mouchoir Bank. However, this theory is improbable due to the "small wax candle" nature of the light, which suggests a point source. A single female Bermuda fireworm Odontosyllis enopla may have separate short periods of excessive and minor brilliance, perhaps accounting for a candle-like display. But later research has shown that Odontosyllis bioluminescent activity is confined to a few days past the full moon, which would rule out that explanation because the Moon was near first quarter that night.