def __get_earth_rotation_since_observation(elapsed_seconds):
"""
convert seconds into angles
total sec/86164.1*360d00.0
:param elapsed_seconds: second between ref time and observed time
:return: hour angle
"""
full_angle = Angle.from_string("360d00.0")
rotation = round(elapsed_seconds / 86164.1000, 5)
print("full_angle_:" + full_angle.str)
print("rotation_:" + str(rotation))
print("get_earth_rotation_:" + Angle.from_decimal(rotation).str)
return Angle.from_decimal(rotation)
