Class: Astronoby::MeanObliquity

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

Constant Summary collapse

EPOCH_OF_REFERENCE =

Source:

IAU resolution in 2006 in favor of the P03 astronomical model
The Astronomical Almanac for 2010

Epoch::DEFAULT_EPOCH
OBLIQUITY_OF_REFERENCE = 
23.4392794

Class Method Summary collapse

Class Method Details

.for_epoch(epoch) ⇒ Object 



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# File 'lib/astronoby/mean_obliquity.rb', line 14

def self.for_epoch(epoch)
  return obliquity_of_reference if epoch == EPOCH_OF_REFERENCE

  t = (epoch - EPOCH_OF_REFERENCE) / Constants::DAYS_PER_JULIAN_CENTURY

  Angle.from_degrees(
    obliquity_of_reference.degrees - (
      46.815 * t -
      0.0006 * t * t +
      0.00181 * t * t * t
    ) / Constants::SECONDS_PER_DEGREE
  )
end

.obliquity_of_reference ⇒ Object 



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# File 'lib/astronoby/mean_obliquity.rb', line 28

def self.obliquity_of_reference
  Angle.from_dms(23, 26, 21.45)
end