{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.654","julian_year":2026.654,"time":"2026-08-27T20:23:17.044Z","years_from_j2000":26.654,"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-189578","name":"HD 189578","class":"f5v_yellow_white_main_sequence_star","category":"star","object_type":"F5V yellow-white main-sequence star","mag":8.62,"mag_band":"V","abs_mag":2.43,"abs_mag_band":"V","distance_ly":564.2844537132487,"distance_method":"parallax","ra_deg":300.05321999999995,"dec_deg":14.90289,"epoch_ra_deg":300.362244,"epoch_dec_deg":14.975986,"epoch_moved_arcsec":0.63,"pm_ra_mas_yr":-19.77,"pm_dec_mas_yr":-12.95,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Aquila","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-189578","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"20002+1454","companions":[{"measured":2014,"magnitude":11.11,"components":"Aa,Ab","discoverer_code":"HDS2847","separation_arcsec":0.4,"position_angle_deg":54},{"measured":2015,"magnitude":15.65,"components":"AB","discoverer_code":"BPM1920","separation_arcsec":77,"position_angle_deg":34}],"spectral_type":"F5V","color_index_bv":0.399,"luminosity_solar":9.28966386779936,"radial_velocity_km_s":4.3,"spectral_type_source":"SIMBAD (quality C)","surface_temperature_k":6910,"proper_motion_ra_mas_yr":-19.77,"proper_motion_dec_mas_yr":-12.95,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"HD","designation":"HD 189578"},{"catalog":"HIP","designation":"HIP 98452"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-27T19:16:43.430Z","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."}