Class: Suntrack

Inherits:
Object
  • Object
show all
Defined in:
lib/suntrack.rb

Overview

Main methods for Ruby version of calculations in “Astronomy on the Personal Computer”, by Montenbruck and Pfleger (1991).

Defined Under Namespace

Classes: Point3D, RAstro

Constant Summary collapse

@@attributes = 
{}

Class Method Summary collapse

Class Method Details

.method_missing(name, *args) ⇒ Object

allow user to create new star location functions User must define declination and right ascension



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# File 'lib/suntrack.rb', line 42

def self.method_missing name, *args
  attribute = name.to_s
  if attribute =~ /=$/
    @@attributes[attribute.chop] = args[0]
  elsif attribute =~ /location/
    @@star = attribute.match(/(\w+)_location/)[1]
    begin
      dt = DateTime.now
      mjd = Suntrack::RAstro.to_mjd(args[0])
      tau = 15 * (Suntrack::RAstro.lmst(mjd,args[2]) - @@attributes["#{@@star}_ra"])
      z_in = Suntrack::Point3D.new(@@attributes["#{@@star}_declination"],tau,args[1])
      z = z_in.equatorial_to_horizon
      z
    rescue Exception => ex
      p "Suntrack ERROR: Please define declination and right ascension for #{@@star}"
    end
  end
end

.sirius_location(date_time, latitude, longitude) ⇒ Suntrack::Point3D

Returns Sirius location, in altitude(sirius_position.y) and azimuth(sirius_position.z), given DateTime, latitude and longitude

Parameters:

  • date_time (DateTime) —

    the date and time for Sirius

  • latitude (Float) —

    the user’s latitude, in degrees

  • longitude (Float) —

    the user’s longitude, in degrees

Returns:



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# File 'lib/suntrack.rb', line 32

def self.sirius_location(date_time,latitude,longitude)
  mjd = Suntrack::RAstro.to_mjd(date_time)
  tau = 15 * (Suntrack::RAstro.lmst(mjd,longitude) - Suntrack::RAstro::SIRIUS_RA)
  z_in = Suntrack::Point3D.new(Suntrack::RAstro::SIRIUS_DECLINATION,tau,latitude)
  sirius_position = z_in.equatorial_to_horizon
  sirius_position
end

.sun_location(date_time, latitude, longitude) ⇒ Suntrack::Point3D

Returns Sun location, in altitude(sun_position.y) and azimuth(sun_position.z), given DateTime, latitude and longitude

Parameters:

  • date_time (DateTime) —

    the date and time for Sun position

  • latitude (Float) —

    the user’s latitude, in degrees

  • longitude (Float) —

    the user’s longitude, in degrees

Returns:



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# File 'lib/suntrack.rb', line 14

def self.sun_location(date_time,latitude,longitude)

  mjd = Suntrack::RAstro.to_mjd(date_time)
  jd = Suntrack::RAstro.jd(mjd)
  tm = Suntrack::RAstro.get_time(jd)
  dec = Suntrack::RAstro.sun_position(tm)
  tau = 15 * (Suntrack::RAstro.lmst(mjd,longitude) - dec.z)
  z_in = Suntrack::Point3D.new(dec.y,tau,latitude)
  sun_position = z_in.equatorial_to_horizon
  sun_position
end