{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.668","julian_year":2026.668,"time":"2026-09-01T21:56:08.894Z","years_from_j2000":26.668,"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-4656","name":"IC 4656","class":"spiral_galaxy_sc","category":"galaxy","object_type":"Spiral galaxy Sc","mag":13.75,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":224859350.5852983,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":264.4327916666667,"dec_deg":-63.72966666666667,"epoch_ra_deg":265.078011,"epoch_dec_deg":-63.745631,"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":"Ara","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ic-4656","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":13.75,"h_mag":10.2,"j_mag":10.97,"k_mag":9.92,"redshift":0.015832,"hubble_type":"Sc","wikidata_id":"Q3681835","redshift_cmb":0.015905619101409307,"ngc_type_code":"G","uncertainties":{"distance_ly":[16798602.26377453,16798602.26377453]},"major_axis_arcmin":2.65,"minor_axis_arcmin":0.57,"position_angle_deg":90,"surface_brightness":23.33,"radial_velocity_km_s":4709},"designations":[{"catalog":"2MASX","designation":"2MASX J17374387-6343466"},{"catalog":"ESO","designation":"ESO 102-010"},{"catalog":"ESO","designation":"ESO 102-10"},{"catalog":"ESO-LV","designation":"ESO-LV 102-0100"},{"catalog":"IC","designation":"IC 4656"},{"catalog":"IRAS","designation":"IRAS 17329-6341"},{"catalog":"LEDA","designation":"LEDA 60595"},{"catalog":"PGC","designation":"PGC 60595"}],"source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-30T09:56:50.739Z","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."}