{"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":"2026-09-08T18:07:15.382Z","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-4423","name":"UGC 4423","class":"spiral_galaxy_scd","category":"galaxy","object_type":"Spiral galaxy Scd","mag":14.646,"mag_band":"B","abs_mag":-19.572159503110605,"abs_mag_band":"B","distance_ly":227540011.56877804,"distance_method":"luminosity distance from a photometric redshift (GLADE+), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":127.722137,"dec_deg":74.687485,"epoch_ra_deg":128.500216,"epoch_dec_deg":74.596976,"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":"Camelopardalis","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ugc-4423","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":14.646,"h_mag":13.002,"j_mag":13.65,"k_mag":12.78,"redshift":0.014772,"hubble_type":"Scd","redshift_cmb":0.0160929899906601,"uncertainties":{"distance_ly":[43351235.05878044,43529190.17550967],"stellar_mass_solar":[840749113.5706705,840749113.5706705]},"major_axis_arcmin":0.94536,"minor_axis_arcmin":0.553792,"morphology_source":"SIMBAD (2003A&A...412...45P, quality E)","position_angle_deg":101,"stellar_mass_solar":1401248522.6177843},"designations":[{"catalog":"2MASX","designation":"2MASX 08305331+7441149"},{"catalog":"PGC","designation":"PGC 23886"},{"catalog":"WISExSCOS","designation":"WISExSCOS J083053.42+744114.6"}],"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."}