{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.673","julian_year":2026.673,"time":"2026-09-03T15:39:43.499Z","years_from_j2000":26.673,"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":"ic-2984","name":"IC 2984","class":"barred_spiral_galaxy_sbd","category":"galaxy","object_type":"Barred spiral galaxy SBd","mag":15.49,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":46305473.28536082,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":179.78012499999997,"dec_deg":30.696944444444444,"epoch_ra_deg":180.125613,"epoch_dec_deg":30.547453,"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":null,"featured":false,"url":"https://spacecatalog.org/object/ic-2984","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":15.49,"h_mag":14.28,"j_mag":14.71,"k_mag":14.07,"redshift":0.00235,"hubble_type":"SBd","wikidata_id":"Q3688358","redshift_cmb":0.0033066637610248417,"ngc_type_code":"G","uncertainties":{"distance_ly":[14136996.466170324,14136996.466170324]},"major_axis_arcmin":0.73,"minor_axis_arcmin":0.49,"position_angle_deg":77,"surface_brightness":23.45,"radial_velocity_km_s":704},"designations":[{"catalog":"IC","designation":"IC 2984"},{"catalog":"LEDA","designation":"LEDA 37734"},{"catalog":"MCG","designation":"MCG +05-28-068"},{"catalog":"PGC","designation":"PGC 37734"}],"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."}