"A Spaceman Came Travelling" (original by Chris de Burgh, numerous covers) is a beautiful song, but sadly has at least two errors:

In the first verse is the line "'Twas light-years of time since his mission did start". No it wasn't; a light-year is a measure of distance, not time -- it's the distance light travels in a year. Singing "'Twas long years of time" instead would fix this.

In the final verse is the line "And just before dawn, at the paling of the sky". But "the paling of the sky" (the twilight period before the rising of the sun) is "dawn"; the rising of the sun itself is "sunrise".