{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.670","julian_year":2026.67,"time":"2026-09-02T18:56:32.625Z","years_from_j2000":26.67,"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-3577","name":"NGC 3577","class":"spiral_galaxy_sa","category":"galaxy","object_type":"Spiral galaxy Sa","mag":14.73,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":262274667.88832435,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":168.43708333333333,"dec_deg":48.27272222222222,"epoch_ra_deg":168.816597,"epoch_dec_deg":48.126634,"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":"1788","featured":false,"url":"https://spacecatalog.org/object/ngc-3577","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":14.73,"h_mag":11.05,"j_mag":11.67,"k_mag":10.9,"redshift":0.0178,"hubble_type":"Sa","wikidata_id":"Q1105449","redshift_cmb":0.01851621966053374,"discovered_by":"William Herschel","ngc_type_code":"G","uncertainties":{"distance_ly":[17679146.68262639,17679146.68262639]},"major_axis_arcmin":1.16,"minor_axis_arcmin":1.01,"position_angle_deg":61,"surface_brightness":23.71,"radial_velocity_km_s":5289},"designations":[{"catalog":"2MASX","designation":"2MASX J11134488+4816212"},{"catalog":"LEDA","designation":"LEDA 34195"},{"catalog":"MCG","designation":"MCG +08-21-006"},{"catalog":"NGC","designation":"NGC 3577"},{"catalog":"PGC","designation":"PGC 34195"},{"catalog":"SDSS","designation":"SDSS J111344.89+481621.7"},{"catalog":"SDSS","designation":"SDSS J111344.89+481621.8"},{"catalog":"SDSS","designation":"SDSS J111344.90+481621.7"},{"catalog":"UGC","designation":"UGC 6257"}],"source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-02T18:38:07.546Z","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."}