{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.679","julian_year":2026.679,"time":"2026-09-05T21:10:56.792Z","years_from_j2000":26.679,"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":"ngc-4478","name":"NGC 4478","class":"elliptical_galaxy_e","category":"galaxy","object_type":"Elliptical galaxy E","mag":11.44,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":81234969.65465124,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":187.57258333333334,"dec_deg":12.328555555555555,"epoch_ra_deg":187.912873,"epoch_dec_deg":12.180067,"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":"Virgo","discovered":"1784","featured":false,"url":"https://spacecatalog.org/object/ngc-4478","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":12.22,"h_mag":8.56,"j_mag":9.25,"k_mag":8.36,"v_mag":11.44,"redshift":0.00469,"hubble_type":"E","wikidata_id":"Q1111826","redshift_cmb":0.005790057199730914,"discovered_by":"William Herschel","ngc_type_code":"G","uncertainties":{"distance_ly":[14416163.491488654,14416163.491488654]},"major_axis_arcmin":1.75,"minor_axis_arcmin":1.43,"wikipedia_article":"NGC 4478","position_angle_deg":144,"surface_brightness":22.3,"radial_velocity_km_s":1403},"designations":[{"catalog":"2MASX","designation":"2MASX J12301743+1219428"},{"catalog":"LEDA","designation":"LEDA 41297"},{"catalog":"MCG","designation":"MCG +02-32-099"},{"catalog":"NGC","designation":"NGC 4478"},{"catalog":"PGC","designation":"PGC 41297"},{"catalog":"SDSS","designation":"SDSS J123017.41+121942.7"},{"catalog":"UGC","designation":"UGC 7645"}],"source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0"},"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."}