Complex sentence: Traditionally, it is celebrated from the very beginning of one Celtic day to its end, or in the modern calendar, from sunset on 31 October to sunset on 1 November, this places it about halfway between the autumn equinox and the winter solstice.
Split into simpler sentences: Traditionally, it is celebrated from the very beginning of one Celtic day to its end, or in the modern calendar, from sunset on 31 October to sunset on 1 November. This places it about halfway between the autumn equinox and the winter solstice.