Natural constants

CONST_C = 299792458.0                        # meters/s
CONST_G = 6.6743E-11                         # m^3 kg/s^2

Solar constants

MASS_SUN = 1.988409870698051E+30             # kg
RADIUS_SUN = 695700000.0                     # meters
LUMINOSITY_SUN = 3.828E26                    # Watts = Joule/s

Distance units

DIST_PC  = 3.085677581491367E+16             # meters
DIST_KPC = 3.085677581491367E+19             # meters
DIST_MPC = 3.085677581491367E+22             # meters
DIST_GPC = 3.085677581491367E+25             # meters

Angular units

ANGLE_MICROARCSEC = 4.848136811095361E-12    # radians
ANGLE_MILLIARCSEC = 4.848136811095361E-09    # radians
ANGLE_ARCSEC = 4.848136811095361E-06         # radians
ANGLE_ARCMIN = 0.0002908882086657216         # radians
ANGLE_DEGREE = 0.017453292519943295          # radians

Temporal units

YEAR2SECOND = 31557600.0                     # Seconds in a year
YEAR2HOUR   = 8766.0                         # Hours in a year
YEAR2DAY    = 365.25                         # Days in a year
DAY2HOUR    = 24.0                           # Hours in a day
DAY2SECOND  = 86400.0                        # Seconds in a day