Winter solstice instant of the solstice can be calculated, direct observation of the solstice by amateurs is impossible because the sun moves too slowly or appears to stand still (the meaning of "solstice"). However, by use of astronomical data tracking, the precise timing of its occurrence is now public knowledge. One cannot directly detect the precise instant of the solstice (by definition, one cannot observe that an object has stopped moving until one later observes that it has not moved further from the preceding spot, or that it has moved in the opposite direction). Further, to be precise to a single day,
Saint Lucy's Day was created on Spring equinox (thought to fall on 25 March at the time), and that Christ had been conceived on that date, being born 9 months later on Winter solstice. A Swedish source states that the date of (Winter Solstice, St. Lucia, Lucinatta, Lucia-day, Lussi-mass ...) i.e. 13 December, predates the Gregorian which implies that "Lucia's Day" "was" 13 Dec in the Julian Calendar, "which is equal to" 21 December in the Gregorian, i.e. now. Same source states use of the name "Little Yule" for the day, that it was among the most important days of the year, that