Determination of the day of the week row C) to find the dominical letter that is E. The letter for September 18 is B, so the day of the week is Thursday. Use 16 (in the Julian century row, column E) and 76 (in row D) to find the dominical letter that is A. February 23 is a "D" day, so the day of the week is Wednesday. In a handwritten note in a collection of astronomical tables, Carl Friedrich Gauss described a method for calculating the day of the week for 1 January in any given year. He never published it. It was finally included in
Eight-day week a day. Further, they also counted the ending night period, giving rise to periods of time with more nights than days. In Irish, the term "nómad" is used to signify a small number of days and is exactly the length of the nine night week as in "co cend nomaide" - a period of time with nine nights bracketing eight days. The nine nights divided nicely into a sidereal month of 27 nights. In Welsh a similar word "wythnos" meaning "a week" literally means "an eight-night" since it started and ended with a period of night bracketing seven days. Similarly