{"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":"2026-09-03T17:57:52.354Z","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":"ngc-4523","name":"NGC 4523","class":"spiral_galaxy_sm","category":"galaxy","object_type":"Spiral galaxy Sm","mag":13.61,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":null,"distance_method":null,"ra_deg":188.45000000000002,"dec_deg":15.168305555555555,"epoch_ra_deg":188.78863,"epoch_dec_deg":15.020155,"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":"Coma Berenices","discovered":"1865","featured":false,"url":"https://spacecatalog.org/object/ngc-4523","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":13.91,"h_mag":10.98,"v_mag":13.61,"redshift":0.00112,"hubble_type":"Sm","wikidata_id":"Q1112242","redshift_cmb":0.002189143586869724,"discovered_by":"Heinrich Louis d'Arrest","ngc_type_code":"G","major_axis_arcmin":1.24,"minor_axis_arcmin":1.15,"wikipedia_article":"NGC 4523","position_angle_deg":0,"surface_brightness":23.06,"radial_velocity_km_s":336},"designations":[{"catalog":"IRAS","designation":"IRAS 12313+1526"},{"catalog":"IRAS","designation":"IRAS F12313+1526"},{"catalog":"LEDA","designation":"LEDA 41746"},{"catalog":"MCG","designation":"MCG +03-32-068"},{"catalog":"NGC","designation":"NGC 4523"},{"catalog":"PGC","designation":"PGC 41746"},{"catalog":"SDSS","designation":"SDSS J123347.74+151001.6"},{"catalog":"SDSS","designation":"SDSS J123347.99+151005.8"},{"catalog":"UGC","designation":"UGC 7713"}],"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."}