{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.678","julian_year":2026.678,"time":"2026-09-05T14:23:23.265Z","years_from_j2000":26.678,"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-6984","name":"NGC 6984","class":"spiral_galaxy_sc","category":"galaxy","object_type":"Spiral galaxy Sc","mag":12.73,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":209980651.0265442,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":314.4749166666667,"dec_deg":-51.87083333333334,"epoch_ra_deg":314.956249,"epoch_dec_deg":-51.767247,"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":"Indus","discovered":"1834","featured":false,"url":"https://spacecatalog.org/object/ngc-6984","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":13.17,"h_mag":10.25,"j_mag":10.94,"k_mag":9.99,"v_mag":12.73,"redshift":0.015386,"hubble_type":"Sc","wikidata_id":"Q966638","redshift_cmb":0.014864701954046433,"discovered_by":"John Frederick William Herschel","ngc_type_code":"G","uncertainties":{"distance_ly":[16473682.873809732,16473682.873809732]},"major_axis_arcmin":1.8,"minor_axis_arcmin":1.16,"wikipedia_article":"NGC 6984","position_angle_deg":101,"surface_brightness":22.82,"radial_velocity_km_s":4577},"designations":[{"catalog":"2MASX","designation":"2MASX J20575398-5152151"},{"catalog":"ESO","designation":"ESO 235-020"},{"catalog":"ESO","designation":"ESO 235-20"},{"catalog":"ESO-LV","designation":"ESO-LV 235-0200"},{"catalog":"IRAS","designation":"IRAS 20543-5203"},{"catalog":"IRAS","designation":"IRAS F20543-5203"},{"catalog":"LEDA","designation":"LEDA 65798"},{"catalog":"NGC","designation":"NGC 6984"},{"catalog":"PGC","designation":"PGC 65798"}],"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."}