Module: AstroChart::Draconic

Defined in:
lib/astro_chart/draconic.rb

Overview

Draconic chart (龍盤): the tropical zodiac rotated so the natal True North Node sits at 0° 牡羊. Every ecliptic longitude is shifted by the node's longitude, which re-signs the whole chart around the lunar nodal axis. Widely read as the "soul level" overlay of the ordinary tropical chart.

draconic_longitude = (L − 北交點) mod 360

Pure composition: this only transforms longitudes. Feed it the raw positions hash from Planets.calculate_positions (or any { name => L } hash) together with the natal True North Node longitude.

Class Method Summary collapse

Class Method Details

.chart(positions, north_node) ⇒ Object

Full draconic view: draconic longitude, zodiac sign and in-sign degree for every body, plus the aspects among them (major aspects only, via Aspects.calculate — draconic-to-draconic contacts are identical to the tropical ones, but the signs and houses they fall in differ).

Returns:

{ "planets" => [ { "planet" =>, "zodiac" =>, "degree" =>,
                 "total_degree" => }, ... ],
"aspects" => [ { "a_planet" =>, "b_planet" =>,
                 "aspect_type" =>, "orb" => }, ... ] }  # sorted by orb


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# File 'lib/astro_chart/draconic.rb', line 34

def self.chart(positions, north_node)
  draconic = self.positions(positions, north_node)

  planets = draconic.map do |name, lon|
    {
      "planet"       => name,
      "zodiac"       => Zodiac.sign_name(lon),
      "degree"       => (lon % 30).round(4),
      "total_degree" => lon.round(4),
    }
  end

  names = draconic.keys
  aspects = []
  names.combination(2) do |a, b|
    type, orb = Aspects.calculate(draconic[a], draconic[b])
    next if type.nil?

    aspects << {
      "a_planet"    => a,
      "b_planet"    => b,
      "aspect_type" => type,
      "orb"         => orb,
    }
  end
  aspects.sort_by! { |asp| asp["orb"] }

  { "planets" => planets, "aspects" => aspects }
end

.positions(positions, north_node) ⇒ Object

positions: { "太陽" => 123.45, ... } tropical ecliptic longitudes north_node: True North Node longitude (degrees, 0-360)

Returns { name => draconic_longitude } with 北交點 mapped to 0.0.



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# File 'lib/astro_chart/draconic.rb', line 20

def self.positions(positions, north_node)
  positions.transform_values { |lon| (lon - north_node) % 360.0 }
end