Add physics script for the light aberration calculation.

physics/light_aberration.py

@@ -0,0 +1,50 @@
+"""
+Title : Calculate Light Aberration (astronomy)
+
+Description :
+ The below algorithm calculates astronomical light aberration as obtained
+ using Special Relativity.
+
+"""
+
+from math import atan, sqrt, tan
+
+
+def get_aberration_angle(angle_rest: float, velocity_over_c: float) -> float:
+ """
+ This method calculates astronomical light aberration.
+ The angle at rest 'angle_rest' is given in radians [rad]
+ and is in the range (-pi, pi).
+ The relative velocity of observer w.r.t. to the light emitting object is
+ expressed by 'velocity_over_c' that is given as ratio for velocity
+ w.r.t. the speed of light c and is in the range (0, 1).
+
+ https://en.wikipedia.org/wiki/Aberration_(astronomy)
+
+ tan(phi/2) = sqrt((1 - v/c)/(1 + v/c)) * tan(theta/2)
+
+ Where v is the relative velocity, phi is the observed angle with respect to the
+ velocity vector (affected by light aberration), and theta is the angle observed
+ angle in the limit of veclocity being equal to 0.
+
+ Examples:
+ >>> get_aberration_angle(0.2, 0.1)
+ 0.18102
+ >>> get_aberration_angle(0.2, 0)
+ 0.2
+ >>> get_aberration_angle(0, 0.2)
+ 0.0
+ >>> get_aberration_angle(-1.5707963267948966, 0.7)
+ -0.7954
+ """
+
+ factor = sqrt((1 - velocity_over_c) / (1 + velocity_over_c))
+ angle_ab = 2 * atan(factor * tan(angle_rest / 2))
+
+ return round(angle_ab, 5)
+
+
+if __name__ == "__main__":
+ import doctest
+
+ doctest.testmod()