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vastro
Coordinates, time and orbital mechanics for the sky, as closed form formulas.
Released v1.0.0 · 2026-09-28use "stdlib/astro.ven"Julian dates, coordinate conversions and orbital mechanics for the sky, written as closed form formulas.
print julian_date(0.0)Reference (7 functions)
API reference
julian_date(epoch_seconds)
Converts a Unix epoch timestamp, in seconds, to a Julian Date.
julian_date(0.0)sidereal_time(julian_date_value, longitude_degrees)
Computes local sidereal time, in degrees, at a given longitude.
sidereal_time(2451545.0, -71.05)equatorial_to_horizontal(right_ascension_deg, declination_deg, latitude_deg, local_sidereal_time_deg)
Converts equatorial coordinates to horizontal (altitude/azimuth) coordinates.
equatorial_to_horizontal(0.0, 45.0, 45.0, 90.0)orbital_period_years(semi_major_axis_au, central_mass_solar_masses)
Computes an orbital period, in years, from Kepler's third law.
orbital_period_years(1.524, 1.0)escape_velocity(mass_kg, radius_m)
Computes the escape velocity from a body's surface, in meters per second.
escape_velocity(5.972 * power(10.0, 24.0), 6371000.0)apparent_magnitude_at_distance(absolute_magnitude, distance_parsecs)
Computes apparent magnitude from an absolute magnitude and a distance.
apparent_magnitude_at_distance(4.83, 10.0)angular_separation(ra1_deg, dec1_deg, ra2_deg, dec2_deg)
Computes the angular separation between two points on the sky, in degrees.
angular_separation(0.0, 0.0, 90.0, 0.0)