{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.668","julian_year":2026.668,"time":"2026-09-01T21:16:00.902Z","years_from_j2000":26.668,"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-147142","name":"20 UMi","class":"k2iv_orange_subgiant","category":"star","object_type":"K2IV orange subgiant","mag":6.36,"mag_band":"V","abs_mag":-0.149,"abs_mag_band":"V","distance_ly":653.6199901953755,"distance_method":"parallax","ra_deg":243.13404000000003,"dec_deg":75.210681,"epoch_ra_deg":242.977286,"epoch_dec_deg":75.141156,"epoch_moved_arcsec":1.501,"pm_ra_mas_yr":-43.51,"pm_dec_mas_yr":35.73,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Ursa Minor","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-147142","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"spectral_type":"K2IV","color_index_bv":1.283,"luminosity_solar":99.90793899844618,"radial_velocity_km_s":-26,"spectral_type_source":"SIMBAD (quality D)","proper_motion_ra_mas_yr":-43.51,"proper_motion_dec_mas_yr":35.73},"designations":[{"catalog":"Bayer/Flamsteed","designation":"20 UMi"},{"catalog":"HD","designation":"HD 147142"},{"catalog":"HIP","designation":"HIP 79420"},{"catalog":"HR","designation":"HR 6082"}],"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."}