A simple Clojure library for getting sunrise and sunset times, given a location, date, and local offset from UTC.
(use 'sunrise.core)
;; Sunset in Paris
(setting-time {:day 1
:month 5
:year 2015
:latitude 48.8567
:longitude 2.3508
:local-offset 1})
;; -> "20:04"
;; Sunrise in Carrboro, NC
(rising-time {:day 25
:month 12
:year 2014
:latitude 35.9206
:longitude -79.0839
:local-offset -5})
;; -> "7:25"
;; Sunrise In Norilsk
(rising-time {:day 1
:month 1
:year 2015
:latitude 69.3333
:longitude 88.2167
:local-offset 7})
;; -> "continuous dark"
;; Sunset at McMurdo Station
(setting-time {:day 1
:month 1
:year 2015
:latitude -77.85
:longitude 166.6667
:local-offset 13})
;; -> "continuous light"As of this writing it is easy to get the latitude and longitude of a town or city by Googling, e.g., "New York City latitude longitude". Similarly, you can usually find the UTC offset for a location by Googling the location with "time" (or "UTC offset").
Note: For this library, West longitudes and South latitudes should be preceded by minus (-) signs.
The algorithm was derived from the Almanac for Computers, 1990, published by Nautical Almanac Office, United States Naval Observatory, Washington, DC 20392, and is described in detail at http:https://williams.best.vwh.net/sunrise_sunset_algorithm.htm
Copyright © 2014 Mark Whelan
Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.