Hour angle The angle may be measured in degrees or in time, with 24 = 360° exactly. In astronomy, hour angle is defined as the angular distance on the celestial sphere measured westward along the celestial equator from the meridian to the hour circle passing through a point. It may be given in degrees, time, or rotations depending on the application. In celestial navigation, the convention is to measure in degrees westward from the prime meridian (Greenwich hour angle, GHA), from the local meridian (local hour angle, LHA) or from the first point of Aries (sidereal hour angle, SHA). The hour angle
Nambu Type 90 Nambu Type 90 The Nambu Type 90 was a flare gun of Japanese origin and manufactured by Nambu. It was used by the Imperial Japanese Navy and came with two or three barrels. The Type 90 designation is from the last two digits of its year of adoption, which was 2590 (or 1930 AD) on the Japanese "Kōki" calendar. It first came with three barrels with just less than 6,000 were manufactured. The First Model (made in the early 1930s during peacetime) was highly polished and finished, while the Second Model (dating from the mid-1930s to the mid-1940s during wartime)