{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.665","julian_year":2026.665,"time":"2026-08-31T22:11:34.287Z","years_from_j2000":26.665,"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":"acrux","name":"Acrux","class":"b0_5iv_b1v_blue_white_subgiant","category":"star","object_type":"B0.5IV+B1V blue-white subgiant","mag":0.77,"mag_band":"V","abs_mag":-4.202,"abs_mag_band":"V","distance_ly":321.97081292150443,"distance_method":"parallax","ra_deg":186.649665,"dec_deg":-63.099092,"epoch_ra_deg":187.023682,"epoch_dec_deg":-63.247872,"epoch_moved_arcsec":1.022,"pm_ra_mas_yr":-35.37,"pm_dec_mas_yr":-14.73,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Crux","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/acrux","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"12266-6306","companions":[{"measured":2024,"magnitude":1.55,"components":"AB","discoverer_code":"DUN 252","separation_arcsec":3.5,"position_angle_deg":111},{"measured":2010,"magnitude":12,"components":"AJ","discoverer_code":"ANT   7","separation_arcsec":29.6,"position_angle_deg":344},{"measured":2013,"magnitude":13,"components":"AH","discoverer_code":"ANT   1","separation_arcsec":47.3,"position_angle_deg":167},{"measured":2014,"magnitude":12,"components":"AG","discoverer_code":"ANT   1","separation_arcsec":58.7,"position_angle_deg":145},{"measured":2013,"magnitude":12,"components":"AI","discoverer_code":"ANT   1","separation_arcsec":63.3,"position_angle_deg":227},{"measured":2020,"magnitude":4.8,"components":"AC","discoverer_code":"DUN 252","separation_arcsec":89,"position_angle_deg":203},{"measured":2010,"magnitude":13,"components":"AK","discoverer_code":"ANT   7","separation_arcsec":125.2,"position_angle_deg":218}],"wikidata_id":"Q66476660","spectral_type":"B0.5IV+B1V","color_index_bv":-0.243,"luminosity_solar":4176.379929509739,"wikipedia_article":"Acrux","radial_velocity_km_s":-11,"spectral_type_source":"SIMBAD (1969ApJ...157..313H, quality C)","proper_motion_ra_mas_yr":-35.37,"proper_motion_dec_mas_yr":-14.73},"designations":[{"catalog":"Bayer/Flamsteed","designation":"Alpha1 Cru"},{"catalog":"Common name","designation":"Acrux"},{"catalog":"HD","designation":"HD 108248"},{"catalog":"HIP","designation":"HIP 60718"},{"catalog":"HR","designation":"HR 4730"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-30T09:56:50.739Z","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."}