{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.664","julian_year":2026.664,"time":"2026-08-31T16:42:44.566Z","years_from_j2000":26.664,"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":"hd-166393","name":"HD 166393","class":"a2v_white_main_sequence_star","category":"star","object_type":"A2V white main-sequence star","mag":6.33,"mag_band":"V","abs_mag":1.297,"abs_mag_band":"V","distance_ly":331.123087036614,"distance_method":"parallax","ra_deg":272.8116,"dec_deg":-19.841958,"epoch_ra_deg":273.209434,"epoch_dec_deg":-19.836657,"epoch_moved_arcsec":0.829,"pm_ra_mas_yr":-3.75,"pm_dec_mas_yr":-30.85,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Sagittarius","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-166393","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"18112-1951","companions":[{"measured":2023,"magnitude":7.13,"components":"AB","discoverer_code":"BU  132","separation_arcsec":1.4,"position_angle_deg":186}],"radius_solar":2.272,"spectral_type":"A2V","color_index_bv":0.158,"luminosity_solar":26.375457408893443,"radial_velocity_km_s":-32,"spectral_type_source":"SIMBAD (1988MSS...C04....0H, quality C)","surface_gravity_log_g":3.795,"surface_temperature_k":7818,"proper_motion_ra_mas_yr":-3.75,"proper_motion_dec_mas_yr":-30.85,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4) — low confidence: above 7,500 K GSP-Phot's temperature and extinction are degenerate"},"designations":[{"catalog":"HD","designation":"HD 166393"},{"catalog":"HIP","designation":"HIP 89114"},{"catalog":"HR","designation":"HR 6798"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-30T09:56:50.739Z","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."}