{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.678","julian_year":2026.678,"time":"2026-09-05T16:48:42.619Z","years_from_j2000":26.678,"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-204710","name":"HD 204710","class":"b8ib_blue_white_supergiant","category":"star","object_type":"B8Ib blue-white supergiant","mag":6.94,"mag_band":"V","abs_mag":-1.459,"abs_mag_band":"V","distance_ly":1560.5568327411474,"distance_method":"parallax","ra_deg":322.276395,"dec_deg":44.923078,"epoch_ra_deg":322.527538,"epoch_dec_deg":45.040139,"epoch_moved_arcsec":0.115,"pm_ra_mas_yr":-2.82,"pm_dec_mas_yr":-3.28,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Cygnus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-204710","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"21291+4455","companions":[{"measured":1876,"magnitude":11,"components":null,"discoverer_code":"BU  448","separation_arcsec":2,"position_angle_deg":-1}],"spectral_type":"B8Ib","color_index_bv":0.25,"luminosity_solar":333.8873767251231,"radial_velocity_km_s":-24,"spectral_type_source":"SIMBAD (quality C)","proper_motion_ra_mas_yr":-2.82,"proper_motion_dec_mas_yr":-3.28},"designations":[{"catalog":"HD","designation":"HD 204710"},{"catalog":"HIP","designation":"HIP 106071"}],"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."}