import numpy as np

# Constants
R_EARTH = np.float64(6378.137)  # [km] Mean equatorial radius
R2_EARTH = np.longdouble(40680631.59076899)  # [km2] mean equat. radius sq.
e_EARTH = np.longdouble(0.081816221456)  # Earth eccentricity
e2_EARTH = np.longdouble(0.006694385000)  # Earth eccentricity squared
MU = np.longdouble(398600.4418)  # [km3/(solar s)2] gravitational parameter
J2 = np.longdouble(0.0010826267)
J2000 = 2451545.0

# Various constants required by Skyfield
AU_M = 149597870700  # per IAU 2012 Resolution B2
AU_KM = 149597870.700
ASEC360 = 1296000.0
DAY_S = 86400.0

# Angles.
ASEC2RAD = 4.848136811095359935899141e-6
DEG2RAD = 0.017453292519943296
RAD2DEG = 57.295779513082321
tau = 6.283185307179586476925287  # lower case, for symmetry with math.pi
