{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.685","julian_year":2026.685,"time":"2026-09-08T03:06:36.255Z","years_from_j2000":26.685,"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-gj-3990","name":"GJ 3990","class":"m_red_star","category":"star","object_type":"M red star","mag":13.99,"mag_band":"V","abs_mag":12.57,"abs_mag_band":"V","distance_ly":62.72248068595149,"distance_method":"parallax","ra_deg":257.46918000000005,"dec_deg":11.923923,"epoch_ra_deg":257.779965,"epoch_dec_deg":11.888923,"epoch_moved_arcsec":10.14,"pm_ra_mas_yr":-368.71,"pm_dec_mas_yr":-91.93,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Ophiuchus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/gliese-gj-3990","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"spectral_type":"m","luminosity_solar":0.0008165823713586,"radial_velocity_km_s":0,"proper_motion_ra_mas_yr":-368.71,"proper_motion_dec_mas_yr":-91.93},"designations":[{"catalog":"Gliese","designation":"GJ 3990"}],"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."}