{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.680","julian_year":2026.68,"time":"2026-09-06T12:21:44.055Z","years_from_j2000":26.68,"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-5983","name":"NGC 5983","class":"elliptical_galaxy_e","category":"galaxy","object_type":"Elliptical galaxy E","mag":15.03,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":599343984.6405226,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":235.690125,"dec_deg":8.24111111111111,"epoch_ra_deg":236.016685,"epoch_dec_deg":8.155265,"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":"Serpens","discovered":"1865","featured":false,"url":"https://spacecatalog.org/object/ngc-5983","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":15.03,"h_mag":10.75,"j_mag":11.39,"k_mag":10.46,"redshift":0.04115,"hubble_type":"E","wikidata_id":"Q1124640","redshift_cmb":0.04160554263482519,"discovered_by":"Albert Marth","ngc_type_code":"G","uncertainties":{"distance_ly":[28120876.102796983,28120876.102796983]},"major_axis_arcmin":0.97,"minor_axis_arcmin":0.92,"position_angle_deg":55,"surface_brightness":23.83,"radial_velocity_km_s":12083},"designations":[{"catalog":"2MASX","designation":"2MASX J15424560+0814279"},{"catalog":"LEDA","designation":"LEDA 55845"},{"catalog":"MCG","designation":"MCG +01-40-012"},{"catalog":"NGC","designation":"NGC 5983"},{"catalog":"PGC","designation":"PGC 55845"},{"catalog":"SDSS","designation":"SDSS J154245.62+081427.9"},{"catalog":"SDSS","designation":"SDSS J154245.63+081427.9"},{"catalog":"SDSS","designation":"SDSS J154245.63+081428.0"},{"catalog":"UGC","designation":"UGC 9983"}],"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."}