Winter solstice one must be able to observe a change in azimuth or elevation less than or equal to about 1/60 of the angular diameter of the sun. Observing that it occurred within a two-day period is easier, requiring an observation precision of only about 1/16 of the angular diameter of the sun. Thus, many observations are of the day of the solstice rather than the instant. This is often done by observing the sunrise and sunset or using an astronomically aligned instrument that allows a ray of light to be cast on a certain point around that time. Length of day
Labours of the Months specifically as their subject matter. Labours of the Months The term Labours of the Months refers to cycles in Medieval and early Renaissance art depicting in twelve scenes the rural activities that commonly took place in the months of the year. They are often linked to the signs of the Zodiac, and are seen as humankind's response to God's ordering of the Universe. The Labours of the Months are frequently found as part of large sculptural schemes on churches, and in illuminated manuscripts, especially in the Calendars of late medieval Books of Hours. The manuscripts are important for the development