{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.670","julian_year":2026.67,"time":"2026-09-02T16:41:13.600Z","years_from_j2000":26.67,"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-4494","name":"IC 4494","class":"lenticular_galaxy_s0_a","category":"galaxy","object_type":"Lenticular galaxy S0-a","mag":15.3,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":725648647.9504452,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":221.10641666666666,"dec_deg":15.551388888888889,"epoch_ra_deg":221.423584,"epoch_dec_deg":15.437513,"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":"Boötes","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ic-4494","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":15.3,"h_mag":12.18,"j_mag":12.88,"k_mag":12.04,"redshift":0.04937,"hubble_type":"S0-a","wikidata_id":"Q3682797","redshift_cmb":0.050070214651412925,"ngc_type_code":"G","uncertainties":{"distance_ly":[32632978.5781348,32632978.5781348]},"major_axis_arcmin":0.93,"minor_axis_arcmin":0.39,"position_angle_deg":136,"surface_brightness":23.83,"radial_velocity_km_s":14436},"designations":[{"catalog":"2MASX","designation":"2MASX J14442552+1533055"},{"catalog":"IC","designation":"IC 4494"},{"catalog":"LEDA","designation":"LEDA 52644"},{"catalog":"MCG","designation":"MCG +03-38-003"},{"catalog":"PGC","designation":"PGC 52644"},{"catalog":"SDSS","designation":"SDSS J144425.53+153304.9"}],"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."}