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 Trailing twelve months Trailing Twelve Months (TTM) is a measurement of a company's financial performance (income and expenses) used in finance. It is measured by using the income statements from a company's reports (such as interim, quarterly or annual reports), to calculate the income for the twelve-month period immediately prior to the date of the report. This figure is calculated by analysts because quarterly and interim reports often show only income from the preceding 3, 6 or 9 months, not a full year. Because it does not represent a full year, this data can be skewed by seasonal trading patterns,