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Ruby script to calculate planetary distances.
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#! /usr/local/bin/ruby | |
# coding: utf-8 | |
#--------------------------------------------------------------------------------- | |
#= JPLEPH(JPL の DE430 バイナリデータ)読込後に座標(位置・速度)を計算し、さらに | |
# 地球から太陽・惑星・月までの距離を計算する。 | |
# : 自作の RubyGems ライブラリ eph_jpl を使用する | |
# (JPL DE430 のバイナリデータが準備済みであること) | |
# | |
# date name version | |
# 2016.07.13 mk-mode.com 1.00 新規作成 | |
# | |
# Copyright(C) 2016 mk-mode.com All Rights Reserved. | |
#--------------------------------------------------------------------------------- | |
# 【引数】 ユリウス日 | |
# (省略可。省略時は現在日時のユリウス日を地球時TT(≒太陽系力学時TDB)とみなす) | |
#--------------------------------------------------------------------------------- | |
#++ | |
require 'eph_jpl' | |
class JplDistanceEarth | |
FILE_BIN = "/path/to/JPLEPH" | |
USAGE = "【使用方法】 ./jpl_distance_earth.rb [ユリウス日]" | |
CENTER = 3 | |
KM = false # true: km, false: AU | |
BODIES = { | |
1 => " 水星 (Mercury)", 2 => " 金星 (Venus) ", 3 => " 地球 (Earth) ", | |
4 => " 火星 (Mars) ", 5 => " 木星 (Jupiter)", 6 => " 土星 (Saturn) ", | |
7 => "天王星 (Uranus) ", 8 => "海王星 (Neptune)", 9 => "冥王星 (Pluto) ", | |
10 => " 月 (Moon) ", 11 => " 太陽 (Sun) " | |
} | |
def initialize | |
@jd = get_args | |
@unit = KM ? "KM" : "AU" | |
end | |
def exec | |
puts "JD(TT) = #{@jd}\n#{BODIES[3]}" | |
BODIES.each do |target, target_name| | |
next if target == 3 | |
eph = EphJpl.new(FILE_BIN, target, CENTER, @jd, KM) | |
ps = eph.calc[0,3] | |
d = calc_distance(ps) | |
d = KM ? sprintf("%19.8f", d) : sprintf("%11.8f", d) | |
puts "- #{target_name} : #{d} #{@unit}" | |
end | |
rescue => e | |
msg = "[#{e.class}] #{e.message}\n" | |
msg << e.backtrace.each { |tr| "\t#{tr}"}.join("\n") | |
$stderr.puts msg | |
exit 1 | |
end | |
private | |
#========================================================================= | |
# コマンドライン引数取得 | |
# | |
# @param: <none> | |
# @return: jd | |
#========================================================================= | |
def get_args | |
jd = ARGV.shift | |
return jd ? jd.to_f : gc2jd({ | |
year: Time.now.strftime("%Y").to_i, | |
month: Time.now.strftime("%m").to_i, | |
day: Time.now.strftime("%d").to_i, | |
hour: Time.now.strftime("%H").to_i, | |
min: Time.now.strftime("%M").to_i, | |
sec: Time.now.strftime("%S").to_i | |
}) | |
rescue => e | |
puts USAGE | |
raise | |
end | |
#========================================================================= | |
# 年月日(グレゴリオ暦)からユリウス日(JD)を計算する | |
# | |
# * フリーゲルの公式を使用する | |
# JD = int(365.25 * year) | |
# + int(year / 400) | |
# - int(year / 100) | |
# + int(30.59 (month - 2)) | |
# + day | |
# + 1721088 | |
# * 上記の int(x) は厳密には、 x を超えない最大の整数 | |
# * 「ユリウス日」でなく「準ユリウス日」を求めるなら、 | |
# `+ 1721088` を `- 678912` とする。 | |
# | |
# @param: hash = { | |
# year(int), month(int), day(int), hour(int), min(int), sec(int) | |
# } | |
# @return: jd (ユリウス日) | |
#========================================================================= | |
def gc2jd(hash) | |
year = hash[:year] | |
month = hash[:month] | |
day = hash[:day] | |
hour = hash[:hour] | |
min = hash[:min] | |
sec = hash[:sec] | |
begin | |
# 1月,2月は前年の13月,14月とする | |
if month < 3 | |
year -= 1 | |
month += 12 | |
end | |
# 日付(整数)部分計算 | |
jd = (365.25 * year).floor \ | |
+ (year / 400.0).floor \ | |
- (year / 100.0).floor \ | |
+ (30.59 * (month - 2)).floor \ | |
+ day \ | |
+ 1721088 | |
# 時間(小数)部分計算 | |
t = (sec / 3600.0 + min / 60.0 + hour) / 24.0 | |
return jd + t | |
rescue => e | |
raise | |
end | |
end | |
#========================================================================= | |
# 距離計算 | |
# | |
# @param: ps (x-座標, y-座標, z-座標) | |
# @return: distance (距離) | |
#========================================================================= | |
def calc_distance(ps) | |
return Math.sqrt(ps.inject(0) { |s, a| s + a * a }) | |
rescue => e | |
raise | |
end | |
end | |
JplDistanceEarth.new.exec if __FILE__ == $0 |
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