{"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":"2026-08-31T19:29:07.222Z","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":"dubhe","name":"Dubhe","class":"g9iii_a7_5_yellow_giant","category":"star","object_type":"G9III+A7.5 yellow giant","mag":1.81,"mag_band":"V","abs_mag":-1.07,"abs_mag_band":"V","distance_ly":122.89246155989176,"distance_method":"parallax","ra_deg":165.93232500000002,"dec_deg":61.751033,"epoch_ra_deg":166.344788,"epoch_dec_deg":61.606225,"epoch_moved_arcsec":3.758,"pm_ra_mas_yr":-136.46,"pm_dec_mas_yr":-35.25,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Ursa Major","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/dubhe","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"11037+6145","companions":[{"measured":2017,"magnitude":4.95,"components":"AB","discoverer_code":"BU 1077","separation_arcsec":0.8,"position_angle_deg":342},{"measured":2020,"magnitude":7.19,"components":"AC","discoverer_code":"BU 1077","separation_arcsec":384.5,"position_angle_deg":206}],"wikidata_id":"Q13084","also_known_as":["Alpha Ursae Majoris","The Celestial Pivot","α UMa","α Ursae Majoris"],"spectral_type":"G9III+A7.5","uncertainties":{"metallicity_fe_h":[0.067,0.067]},"color_index_bv":1.061,"luminosity_solar":233.3458062281002,"metallicity_fe_h":-0.19,"wikipedia_article":"Dubhe","radial_velocity_km_s":-9,"spectral_type_source":"SIMBAD (2014yCat....1.2023S, quality C)","surface_gravity_log_g":2.23,"surface_temperature_k":4648,"metallicity_fe_h_source":"Median of 4 spectroscopic determinations in 4 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":-136.46,"proper_motion_dec_mas_yr":-35.25,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"Bayer/Flamsteed","designation":"50 Alpha UMa"},{"catalog":"Common name","designation":"Dubhe"},{"catalog":"HD","designation":"HD 95689"},{"catalog":"HIP","designation":"HIP 54061"},{"catalog":"HR","designation":"HR 4301"},{"catalog":"IRAS","designation":"IRAS 11006+6201"}],"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."}