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skyfield.starlib.
Star
(ra=None, dec=None, ra_hours=None, dec_degrees=None, ra_mas_per_year=0.0, dec_mas_per_year=0.0, parallax_mas=0.0, radial_km_per_s=0.0, names=(), epoch=2451545.0)¶The position in the sky of a star or other fixed object.
Each Star
object specifies the position of a distant object. You
should provide as a right ascension and declination relative to the
ICRS (the recent improvement upon J2000). You can specify the
coordinates using either floating point hours and degrees, or tuples
that specify hour and degree fractions as minutes and seconds, or
even full Skyfield Angle
objects (which can
themselves be initialized using hours, degrees, or radians):
>>> barnard = Star(ra_hours=17.963471675, dec_degrees=4.69339088889)
>>> barnard = Star(ra_hours=(17, 57, 48.49), dec_degrees=(4, 41, 36.20))
>>> barnard = Star(ra=Angle(hours=17.963471675),
... dec=Angle(degrees=4.69339088889))
For objects whose proper motion across the sky has been detected, you can supply velocities in milliarcseconds (mas) per year, and even a parallax and radial velocity if those are known:
>>> barnard = Star(ra_hours=(17, 57, 48.49803),
... dec_degrees=(4, 41, 36.2072),
... ra_mas_per_year=-798.71,
... dec_mas_per_year=+10337.77,
... parallax_mas=545.4,
... radial_km_per_s=-110.6)
See Stars and Distant Objects for a guide to using a Star
once you have created it.