{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.671","julian_year":2026.671,"time":"2026-09-03T00:36:22.473Z","years_from_j2000":26.671,"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-33918","name":"HD 33918","class":"a3iii_white_giant","category":"star","object_type":"A3III white giant","mag":7.68,"mag_band":"V","abs_mag":1.751,"abs_mag_band":"V","distance_ly":500.2397350720335,"distance_method":"parallax","ra_deg":78.36933,"dec_deg":-4.652908,"epoch_ra_deg":78.701456,"epoch_dec_deg":-4.621077,"epoch_moved_arcsec":0.528,"pm_ra_mas_yr":-7.83,"pm_dec_mas_yr":-18.2,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Orion","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-33918","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"05135-0439","age_years":816610800,"companions":[{"measured":2015,"magnitude":12.21,"components":null,"discoverer_code":"HJ 2257","separation_arcsec":32.8,"position_angle_deg":271}],"mass_solar":1.851,"radius_solar":2.158,"spectral_type":"A3III","color_index_bv":0.201,"luminosity_solar":17.362009919014184,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1999MSS...C05....0H, quality C)","surface_gravity_log_g":3.856,"surface_temperature_k":7994,"proper_motion_ra_mas_yr":-7.83,"proper_motion_dec_mas_yr":-18.2,"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","bolometric_luminosity_solar":15.4968},"designations":[{"catalog":"HD","designation":"HD 33918"},{"catalog":"HIP","designation":"HIP 24345"}],"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."}