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
Dump months thus attract major releases throughout the year, the two that occur during these months—Martin Luther King Day in January and Presidents' Day in February—offer only a modest prospect for improvement. The most lucrative take by any movie on Martin Luther King Day weekend is $107.2 million by "American Sniper" in 2015, its first weekend in wide release; the previous best opening weekend was "Ride Along" the previous year, taking in $41.5 million ($48.6 million if the entire three-day holiday weekend is counted). Presidents' Day benefits by its proximity to Valentine's Day (which, as it is always February 14, is often