{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.669","julian_year":2026.669,"time":"2026-09-02T09:57:22.168Z","years_from_j2000":26.669,"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-5477","name":"NGC 5477","class":"spiral_galaxy_sm","category":"galaxy","object_type":"Spiral galaxy Sm","mag":13.78,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":null,"distance_method":null,"ra_deg":211.38875000000002,"dec_deg":54.46113888888889,"epoch_ra_deg":211.626406,"epoch_dec_deg":54.332498,"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":"Ursa Major","discovered":"1789","featured":false,"url":"https://spacecatalog.org/object/ngc-5477","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":14.37,"v_mag":13.78,"redshift":0.001057,"hubble_type":"Sm","wikidata_id":"Q1120151","redshift_cmb":0.0014528081902402956,"discovered_by":"William Herschel","ngc_type_code":"G","major_axis_arcmin":1.11,"minor_axis_arcmin":0.78,"wikipedia_article":"NGC 5477","position_angle_deg":87,"surface_brightness":23.02,"radial_velocity_km_s":317},"designations":[{"catalog":"IRAS","designation":"IRAS F14038+5441"},{"catalog":"LEDA","designation":"LEDA 50262"},{"catalog":"MCG","designation":"MCG +09-23-034"},{"catalog":"NGC","designation":"NGC 5477"},{"catalog":"PGC","designation":"PGC 50262"},{"catalog":"SDSS","designation":"SDSS J140533.29+542740.1"},{"catalog":"UGC","designation":"UGC 9018"}],"source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-01T22:58:55.274Z","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."}