com.climate.astro-algo.bodies — astro-algo 0.2.0

Protocol, classes and functions for celestial bodies References: [1] Meeus, Jean. Astronomical Algorithms 2nd Ed. Willman-Bell, Inc. 1998.

Body clj protocol

Protocol for a celestial body

equatorial-coordinates clj

(equatorial-coordinates this dt)

Calculate apparent right ascension and declination of a body. Input: this (Body instance) dt (org.joda.time.DateTime UTC) Returns a map with keys: :right-ascension (radians west of Greenwich) :declination (radians north of the celestial equator)

standard-altitude clj

(standard-altitude this)

Returns the "standard" altitude, i.e. the geometric altitude of the center of the body at the time of apparent rising or setting Input: this (Body instance) Returns standard altitude (degrees)

local-coordinates clj

(local-coordinates body dt lon lat)

Calculate local coordinates of a celestial body Input: body (Body instance) dt (org.joda.time.DateTime UTC) lon - longitude (degrees East of Greenwich) lat - latitude (degrees North of the Equator) Returns a map with keys: :azimuth (radians westward from the South) :altitude (radians above the horizon)

passages clj

(passages body
          date
          lon
          lat
          &
          {:keys [include-twilight precision] :or {precision 0.1}})

Calculate the UTC times of rising, transit and setting of a celestial body Input: body (Body instance) date (org.joda.time.LocalDate) lon - longitude (degrees East of Greenwich) lat - latitude (degrees North of the Equator) opts :include-twilight (one of "civil" "astronomical" "nautical" default nil) :precision - iterate until corrections are below this (degrees, default 0.1) Returns a map with keys: :rising (org.joda.time.DateTime UTC) :transit (org.joda.time.DateTime UTC) :setting (org.joda.time.DateTime UTC)