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
Trailing twelve months such as higher sales over Christmas, giving a less accurate picture of a company's fiscal health. Typically trailing twelve months figures are generated to show either the most recent twelve months of a company's trading or to show the last twelve months of its trading before a certain event, such as an acquisition, took place. If no quarterly or interim report has been issued between the last preliminary report or annual report and the date in question, then there is no need to generate trailing twelve months figures, because annual and preliminary reports already contain figures for 12 months. Trailing