{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.672","julian_year":2026.672,"time":"2026-09-03T11:17:18.127Z","years_from_j2000":26.672,"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-3198","name":"NGC 3198","class":"spiral_galaxy_sc","category":"galaxy","object_type":"Spiral galaxy Sc","mag":10.38,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":42013413.8442398,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":154.97895833333334,"dec_deg":45.54961111111111,"epoch_ra_deg":155.388933,"epoch_dec_deg":45.414889,"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-3198","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":10.9,"h_mag":8.06,"j_mag":8.73,"k_mag":7.78,"v_mag":10.38,"redshift":0.00227,"hubble_type":"Sc","wikidata_id":"Q1103488","redshift_cmb":0.003000865994457369,"discovered_by":"William Herschel","ngc_type_code":"G","uncertainties":{"distance_ly":[14111988.360910699,14111988.360910699]},"major_axis_arcmin":6.46,"minor_axis_arcmin":1.84,"wikipedia_article":"NGC 3198","position_angle_deg":30,"surface_brightness":22.68,"radial_velocity_km_s":680},"designations":[{"catalog":"2MASX","designation":"2MASX J10195499+4532588"},{"catalog":"IRAS","designation":"IRAS 10168+4548"},{"catalog":"IRAS","designation":"IRAS F10168+4547"},{"catalog":"LEDA","designation":"LEDA 30197"},{"catalog":"MCG","designation":"MCG +08-19-020"},{"catalog":"NGC","designation":"NGC 3198"},{"catalog":"PGC","designation":"PGC 30197"},{"catalog":"SDSS","designation":"SDSS J101954.92+453259.0"},{"catalog":"SDSS","designation":"SDSS J101954.92+453259.1"},{"catalog":"UGC","designation":"UGC 5572"}],"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."}