{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.669","julian_year":2026.669,"time":"2026-09-02T10:30:11.474Z","years_from_j2000":26.669,"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-4978","name":"IC 4978","class":"spiral_galaxy","category":"galaxy","object_type":"Spiral galaxy","mag":15.45,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":200856628.21336052,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":303.656875,"dec_deg":-54.42197222222222,"epoch_ra_deg":304.175818,"epoch_dec_deg":-54.340483,"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":"Telescopium","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ic-4978","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":15.45,"h_mag":11.91,"j_mag":12.66,"k_mag":11.58,"redshift":0.01462,"hubble_type":"3.5","wikidata_id":"Q3681152","redshift_cmb":0.014225595434493643,"ngc_type_code":"G","uncertainties":{"distance_ly":[16282135.472568007,16282135.472568007]},"major_axis_arcmin":0.74,"minor_axis_arcmin":0.3,"morphology_source":"SIMBAD (1989ESOLV.C......0L, quality D)","position_angle_deg":91,"surface_brightness":23.54,"radial_velocity_km_s":4350},"designations":[{"catalog":"2MASX","designation":"2MASX J20143763-5425190"},{"catalog":"ESO","designation":"ESO 186-018"},{"catalog":"ESO","designation":"ESO 186-18"},{"catalog":"ESO-LV","designation":"ESO-LV 186-0180"},{"catalog":"IC","designation":"IC 4978"},{"catalog":"LEDA","designation":"LEDA 64338"},{"catalog":"PGC","designation":"PGC 64338"}],"source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-01T22:58:55.274Z","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."}