Longitude of the periapsis α = 237.38°, δ = +0.41° and ϖ = 235.00°, b = +19.97° (Brown actually provides i, Ω, and ϖ, from which ω was computed). Reference: Brown, Michael E. (2017) “Planet Nine: where are you? (part 1)” The Search for Planet Nine. Longitude of the periapsis In celestial mechanics, the longitude of the periapsis, also called longitude of the pericenter, of an orbiting body is the longitude (measured from the point of the vernal equinox) at which the periapsis (closest approach to the central body) would occur if the body's orbit inclination were zero. It is usually denoted "ϖ". For
The Nautical Almanac The Nautical Almanac The Nautical Almanac has been the familiar name for a series of official British almanacs published under various titles since the first issue of "The Nautical Almanac and Astronomical Ephemeris", for 1767: this was the first nautical almanac to contain data dedicated to the convenient determination of longitude at sea. It was originally published from the Royal Greenwich Observatory in England. A detailed account of how the publication was produced in its earliest years has been published by the National Maritime Museum. Since 1958 (with the issue for the year 1960), [[Her Majesty's Nautical Almanac Office]] and