{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.674","julian_year":2026.674,"time":"2026-09-04T03:27:23.675Z","years_from_j2000":26.674,"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-4189","name":"NGC 4189","class":"spiral_galaxy_sc","category":"galaxy","object_type":"Spiral galaxy Sc","mag":11.84,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":114420793.28473634,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":183.44695833333333,"dec_deg":13.424805555555555,"epoch_ra_deg":183.789342,"epoch_dec_deg":13.275456,"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":"1784","featured":false,"url":"https://spacecatalog.org/object/ngc-4189","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":12.52,"h_mag":9.33,"j_mag":9.95,"k_mag":8.91,"v_mag":11.84,"redshift":0.00702,"hubble_type":"Sc","wikidata_id":"Q1109655","redshift_cmb":0.008140917566697992,"discovered_by":"William Herschel","ngc_type_code":"G","uncertainties":{"distance_ly":[14800845.201481545,14800845.201481545]},"major_axis_arcmin":2.2,"minor_axis_arcmin":1.79,"wikipedia_article":"NGC 4189","position_angle_deg":87,"surface_brightness":22.79,"radial_velocity_km_s":2097},"designations":[{"catalog":"2MASX","designation":"2MASX J12134727+1325294"},{"catalog":"IC","designation":"IC 3050"},{"catalog":"IRAS","designation":"IRAS 12112+1342"},{"catalog":"IRAS","designation":"IRAS F12112+1342"},{"catalog":"LEDA","designation":"LEDA 39025"},{"catalog":"MCG","designation":"MCG +02-31-054"},{"catalog":"NGC","designation":"NGC 4189"},{"catalog":"PGC","designation":"PGC 39025"},{"catalog":"SDSS","designation":"SDSS J121347.26+132529.2"},{"catalog":"SDSS","designation":"SDSS J121347.27+132529.3"},{"catalog":"UGC","designation":"UGC 7235"}],"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."}