{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.683","julian_year":2026.683,"time":"2026-09-07T14:36:48.807Z","years_from_j2000":26.683,"frame":"date","applied":"Proper motion, then precession and nutation. The catalogued J2000 position is carried along the great circle the object's own published motion puts it on, at a constant velocity, and the result is referred to the true equator and equinox of this instant. Those are separate things: the motion moves the object, and the rotation turns the grid under it by about fifty arcseconds a year, with nutation adding up to another seventeen.","excluded":"Parallax, the radial-velocity perspective term, aberration and refraction; each is below the accuracy of the catalogued positions themselves. An object with no published proper motion comes back where the catalogue has it rather than at a fabricated zero, and says so with a null pm_ra_mas_yr. A body with no fixed position is not propagated at all — its place comes from an ephemeris, which is what /api/v1/visible answers with."},"slug":"gliese-gl-491b","name":"Gl 491B","class":"star","category":"star","object_type":null,"mag":12.5,"mag_band":"V","abs_mag":10.888,"abs_mag_band":"V","distance_ly":68.52023645624433,"distance_method":"parallax","ra_deg":194.756835,"dec_deg":-9.833879,"epoch_ra_deg":195.101217,"epoch_dec_deg":-9.977536,"epoch_moved_arcsec":22.681,"pm_ra_mas_yr":-826.51,"pm_dec_mas_yr":198.43,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Virgo","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/gliese-gl-491b","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"luminosity_solar":0.0038441471175957743,"radial_velocity_km_s":0,"proper_motion_ra_mas_yr":-826.51,"proper_motion_dec_mas_yr":198.43},"designations":[{"catalog":"Gliese","designation":"Gl 491B"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-02T19:50:56.720Z","attribution":"Data from SpaceCatalog.org. Individual records carry their source and license in `source`; attribution is required for CC-BY and CC-BY-SA rows."}