{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.684","julian_year":2026.684,"time":"2026-09-07T23:27:37.349Z","years_from_j2000":26.684,"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-163800","name":"HD 163800","class":"o7_5iii_f_blue_giant","category":"star","object_type":"O7.5III((f)) blue giant","mag":7,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":null,"distance_method":null,"ra_deg":269.738565,"dec_deg":-22.517549,"epoch_ra_deg":270.144841,"epoch_dec_deg":-22.520029,"epoch_moved_arcsec":0.096,"pm_ra_mas_yr":-2.18,"pm_dec_mas_yr":-2.84,"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-163800","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"17590-2231","companions":[{"measured":2012,"magnitude":13.66,"components":"AB","discoverer_code":"SNA  75","separation_arcsec":3.9,"position_angle_deg":221},{"measured":2012,"magnitude":12.74,"components":"AC","discoverer_code":"SNA  75","separation_arcsec":6.2,"position_angle_deg":46},{"measured":2012,"magnitude":11.82,"components":"AD","discoverer_code":"SNA  75","separation_arcsec":6.9,"position_angle_deg":302},{"measured":2012,"magnitude":12.34,"components":"AE","discoverer_code":"SNA  75","separation_arcsec":7.9,"position_angle_deg":349}],"radius_solar":27.305,"spectral_type":"O7.5III((f))","color_index_bv":0.232,"radial_velocity_km_s":4.3,"spectral_type_source":"SIMBAD (2014ApJS..211...10S, quality C)","surface_gravity_log_g":2.171,"surface_temperature_k":6678,"proper_motion_ra_mas_yr":-2.18,"proper_motion_dec_mas_yr":-2.84,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)"},"designations":[{"catalog":"HD","designation":"HD 163800"},{"catalog":"HIP","designation":"HIP 88040"}],"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."}