{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.687","julian_year":2026.687,"time":"2026-09-08T23:30:33.188Z","years_from_j2000":26.687,"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":"ugc-10303","name":"UGC 10303","class":"spiral_galaxy","category":"galaxy","object_type":"Spiral galaxy","mag":14.573,"mag_band":"B","abs_mag":-20.251613030575193,"abs_mag_band":"B","distance_ly":300848937.0009809,"distance_method":"luminosity distance from a spectroscopic redshift (GLADE+), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":243.983658,"dec_deg":31.406874,"epoch_ra_deg":244.246515,"epoch_dec_deg":31.339475,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Corona Borealis","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ugc-10303","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":14.573,"h_mag":12.653,"j_mag":13.359,"k_mag":12.286,"redshift":0.02256,"hubble_type":"5.40","redshift_cmb":0.0211973431328596,"uncertainties":{"distance_ly":[16075735.553175543,16080965.435127044],"stellar_mass_solar":[1868271401.708485,1868271401.708485]},"major_axis_arcmin":0.995277,"minor_axis_arcmin":0.424685,"morphology_source":"SIMBAD (2022MNRAS.513..389R, quality C)","position_angle_deg":86,"stellar_mass_solar":4670678504.271213},"designations":[{"catalog":"2MASX","designation":"2MASX 16155607+3124247"},{"catalog":"PGC","designation":"PGC 57654"},{"catalog":"WISExSCOS","designation":"WISExSCOS J161556.17+312424.5"}],"source":{"id":"glade_plus","name":"GLADE+ (Galaxy List for the Advanced Detector Era)","url":"https://cdsarc.cds.unistra.fr/viz-bin/cat/VII/291","license":"VizieR terms; cite Dalya+ 2022 (2022MNRAS.514.1403D)"},"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."}