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
Circle of equal altitude Circle of equal altitude The circle of equal altitude also called circle of position, CoP, is the real line of position in celestial navigation. It is defined as the locus of the Earth on which an observer sees a star, at a given time, with the same observed altitude. The center of the CoP, is the substellar point or geographical position of the observed body, and its radius is the great circle distance equal to the zenith distance of the body. The equation links the following variables formula_1 Being "B" the latitude (+N/S), "L" the longitude (+E/-W). "LHA" = "GHA"