{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.666","julian_year":2026.666,"time":"2026-09-01T06:01:06.924Z","years_from_j2000":26.666,"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-4928","name":"IC 4928","class":"galaxy","category":"galaxy","object_type":"Galaxy","mag":15.98,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":629087571.0379755,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":302.55,"dec_deg":-77.30897222222222,"epoch_ra_deg":303.454376,"epoch_dec_deg":-77.229509,"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":"Octans","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ic-4928","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":15.98,"h_mag":12,"j_mag":12.85,"k_mag":11.53,"redshift":0.043653,"wikidata_id":"Q3681514","redshift_cmb":0.04360768379930913,"ngc_type_code":"G","uncertainties":{"distance_ly":[29166414.089228716,29166414.089228716]},"major_axis_arcmin":0.9,"minor_axis_arcmin":0.27,"position_angle_deg":33,"surface_brightness":24.5,"radial_velocity_km_s":12801},"designations":[{"catalog":"2MASX","designation":"2MASX J20101200-7718324"},{"catalog":"ESO","designation":"ESO 046-006"},{"catalog":"ESO","designation":"ESO 46-6"},{"catalog":"IC","designation":"IC 4928"},{"catalog":"IRAS","designation":"IRAS 20034-7727"},{"catalog":"LEDA","designation":"LEDA 64198"},{"catalog":"PGC","designation":"PGC 64198"}],"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."}