18 inches; derived from distance between elbow and tip of middle finger.
Last 7 Days
The Moon is highest above or farthest below the celestial equator.
A tide with one high water and one low water every half day. East Coast tides, for example, are semidiurnal, with two highs and two lows during a tidal day of approximately 24 hours.
When the Sun crosses the celestial equator. This occurs two times each year: Vernal around March 21 and Autumnal around September 23.
The full Moon enters the shadow of Earth, which cuts off all or part of the Moon’s light. Total: The Moon passes completely through the umbra (central dark part) of Earth’s shadow. Partial: Only part of the Moon passes through the umbra. Penumbral: The Moon passes through only the penumbra (area of partial darkness surrounding the umbra).
Period betweenthe last killing frost in spring and first killing frost in fall.
A cloud yardstick. A ceilometer measures the height of clouds.
Fear of clouds