{"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":"2026-09-05T18:49:35.557Z","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-203633","name":"HD 203633","class":"a5iv_white_subgiant","category":"star","object_type":"A5IV white subgiant","mag":7.27,"mag_band":"V","abs_mag":2.215,"abs_mag_band":"V","distance_ly":334.51935339777845,"distance_method":"parallax","ra_deg":320.84892,"dec_deg":2.766252,"epoch_ra_deg":321.18848,"epoch_dec_deg":2.880955,"epoch_moved_arcsec":0.569,"pm_ra_mas_yr":16.13,"pm_dec_mas_yr":-13.97,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Equuleus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-203633","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"age_years":678106600,"mass_solar":1.68,"radius_solar":1.713,"spectral_type":"A5IV","color_index_bv":0.213,"luminosity_solar":11.324003632355572,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1999MSS...C05....0H, quality C)","surface_gravity_log_g":4.016,"surface_temperature_k":7821,"proper_motion_ra_mas_yr":16.13,"proper_motion_dec_mas_yr":-13.97,"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; Gaia's classifier calls the source a binary, which GSP-Phot fitted as one star","bolometric_luminosity_solar":9.4192},"designations":[{"catalog":"HD","designation":"HD 203633"},{"catalog":"HIP","designation":"HIP 105608"}],"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."}