Class: VORuby::CoordinateSystems::Equatorial::RightAscension

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

Constant Summary collapse

MIN_ALLOWED_VALUE = 
0.0
MAX_ALLOWED_VALUE = 
360.0

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(ra) ⇒ RightAscension

Create a RightAscenson object.



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# File 'lib/voruby/spacetime/spacetime.rb', line 294

def initialize(ra)
  self.value = ra
end

Instance Attribute Details

#value ⇒ Object

Returns the value of attribute value.



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# File 'lib/voruby/spacetime/spacetime.rb', line 288

def value
  @value
end

Class Method Details

.from_sexigesimal(ra) ⇒ Object

Create a RightAscension object from a string in sexigesimal format. Numerical values may be separated by a space or colon (but not both).

Raises:



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# File 'lib/voruby/spacetime/spacetime.rb', line 322

def self.from_sexigesimal(ra)
  raise Exception::InvalidSexigesimalFormat.new(ra) if !Equatorial::looks_like_sexigesimal?(ra)

  hours_s, minutes_s, seconds_s = ra.split(/:|\s+/)

  hours = hours_s.to_f
  minutes = minutes_s.to_f
  seconds = seconds_s.to_f

  ra_degrees = 15.0 * (hours + (minutes + seconds.to_f / 60.0) / 60.0)
  return RightAscension.new(ra_degrees)
end

.in_range?(ra) ⇒ Boolean

Is the supplied number in the correct range for a right ascension (i.e between 0 and 360 degrees)?

Returns:

  • (Boolean) 


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# File 'lib/voruby/spacetime/spacetime.rb', line 316

def self.in_range?(ra)
  (MIN_ALLOWED_VALUE..MAX_ALLOWED_VALUE) === ra
end

Instance Method Details

#+(degrees) ⇒ Object

Returns a RightAscension object projected forward the specified number of degrees.



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# File 'lib/voruby/spacetime/spacetime.rb', line 347

def +(degrees)
  new_degrees = self.value + degrees
  new_degrees = new_degrees - MAX_ALLOWED_VALUE if new_degrees > MAX_ALLOWED_VALUE

  RightAscension.new(new_degrees)
end

#-(degrees) ⇒ Object

Returns a RightAscension object projected backward the specified number of degrees.



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# File 'lib/voruby/spacetime/spacetime.rb', line 362

def -(degrees)
  new_degrees = self.value - degrees
  new_degrees = MAX_ALLOWED_VALUE + new_degrees if new_degrees < MIN_ALLOWED_VALUE

  RightAscension.new(new_degrees)
end

#<=>(ra) ⇒ Object 



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# File 'lib/voruby/spacetime/spacetime.rb', line 375

def <=>(ra)
  self.value <=> ra.value
end

#==(ra) ⇒ Object 



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# File 'lib/voruby/spacetime/spacetime.rb', line 379

def ==(ra)
  self.value == ra.value
end

#decrement(degrees) ⇒ Object

Subtract the specified number of degrees from the ra.



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# File 'lib/voruby/spacetime/spacetime.rb', line 370

def decrement(degrees)
  new_degrees = self - degrees
  self.value = new_degrees.value
end

#increment(degrees) ⇒ Object

Add the specified number of degrees to the ra.



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# File 'lib/voruby/spacetime/spacetime.rb', line 355

def increment(degrees)
  new_degrees = self + degrees
  self.value = new_degrees.value
end

#to_s ⇒ Object 



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# File 'lib/voruby/spacetime/spacetime.rb', line 383

def to_s
  "#{self.to_sexigesimal}"
end

#to_sexigesimal(sep = ':') ⇒ Object

Return the value of the ra as a string in sexigesimal format.



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# File 'lib/voruby/spacetime/spacetime.rb', line 336

def to_sexigesimal(sep=':')
  rah = (self.value / 15.0).to_i()
  ram = ((self.value - 15.0 * rah) * (60.0 / 15.0)).to_i()
  ras = self.value - (rah * 15.0) - (ram / (60.0 / 15.0))
  ras = ras * (60.0 * 60.0 / 15.0)

  return sprintf("%02u#{sep}%02u#{sep}%0.2f", rah, ram, ras)
end