EphJcg

Introduction

This is the gem library which calculates ephemeris datas by JCG(Japan Coast Guard) method.

Computable items

  • Sun
    • R.A.(= Right Ascension, Alpha, Unit: h)
    • Dec.(= Declination, Delta, Unit: °)
    • Dist.(= Distance, Unit: AU)
    • h(= Greenwich hour angle, Unit: h)
    • S.D.(= Apparent Semidiameter, Unit: ′)
    • Lambda(= Ecliptic longitude, Unit: °)
    • Beta(= Ecliptic latitude, Unit: °)
  • Moon
    • R.A.(= Right Ascension, Alpha, Unit: h)
    • Dec.(= Declination, Delta, Unit: °)
    • H.P.(= Horizontal Parallax, Unit: °)
    • h(= Greenwich hour angle, Unit: h)
    • S.D.(= Apparent Semidiameter, Unit: ′)
    • Lambda(= Ecliptic longitude, Unit: °)
    • Beta(= Ecliptic latitude, Unit: °)
  • R (Unit: h)
  • Epsilon(= Mean obliquity of the ecliptic, Unit: °)
  • Lambda difference between Sun and Moon (Unit: °)

Installation

Add this line to your application's Gemfile:

gem 'eph_jcg'

And then execute:

$ bundle

Or install it yourself as:

$ gem install eph_jcg

Usage

Instantiation

require 'eph_jcg'

obj = EphJcg.new
obj = EphJcg.new("20160603")
obj = EphJcg.new("20160603123059")

Calculation

obj.calc_all

# Otherwise
obj.calc_sun_ra
obj.calc_sun_dec
obj.calc_sun_dist
obj.calc_moon_ra
obj.calc_moon_dec
obj.calc_moon_hp
obj.calc_r
obj.calc_eps
obj.calc_sun_h
obj.calc_moon_h
obj.calc_sun_sd
obj.calc_moon_sd
obj.calc_sun_lambda
obj.calc_sun_beta
obj.calc_moon_lambda
obj.calc_moon_beta
obj.calc_lambda_s_m

Getting values

obj.display_all

# Otherwise
p obj.jst
p obj.utc
p obj.sun_ra
p obj.sun_dec
p obj.sun_dist
p obj.moon_ra
p obj.moon_dec
p obj.moon_hp
p obj.r
p obj.eps
p obj.sun_h
p obj.moon_h
p obj.sun_sd
p obj.moon_sd
p obj.sun_lambda
p obj.sun_beta
p obj.moon_lambda
p obj.moon_beta
p obj.lambda_s_m

# etc...
p obj.hour2hms(obj.sun_ra)
p obj.deg2dms(obj.sun_dec)

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment. Run bundle exec eph_jcg to use the gem in this directory, ignoring other installed copies of this gem.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/komasaru/eph_jcg.

License

The gem is available as open source under the terms of the MIT License.