{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.673","julian_year":2026.673,"time":"2026-09-03T23:27:38.013Z","years_from_j2000":26.673,"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":"pgc-4572928","name":"PGC 4572928","class":"irregular_galaxy_di","category":"galaxy","object_type":"Irregular galaxy dI","mag":18.01,"mag_band":"B","abs_mag":-13.383446362091131,"abs_mag_band":"B","distance_ly":61960533.37297071,"distance_method":"luminosity distance from a photometric redshift (GLADE+), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":154.323,"dec_deg":22.16102,"epoch_ra_deg":154.69403,"epoch_dec_deg":22.027061,"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":"Leo","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/pgc-4572928","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":18.01,"redshift":0.00488124244062,"hubble_type":"dI","redshift_cmb":0.0044208475187297,"uncertainties":{"distance_ly":[14309162.616251763,14328558.229746314],"stellar_mass_solar":[6539640.372597083,6539640.372597083]},"major_axis_arcmin":0.256483,"minor_axis_arcmin":0.163431,"morphology_source":"SIMBAD (2015ApJS..217...27A, quality C)","position_angle_deg":179,"stellar_mass_solar":10276577.728366844},"designations":[{"catalog":"PGC","designation":"PGC 4572928"},{"catalog":"SDSSJ","designation":"SDSSJ 101717.58+220939.3"},{"catalog":"WISExSCOS","designation":"WISExSCOS J101717.57+220939.7"}],"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."}