{"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":"2026-09-02T04:11:40.293Z","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-3958","name":"IC 3958","class":"elliptical_galaxy_e","category":"galaxy","object_type":"Elliptical galaxy E","mag":16.71,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":1095525811.0706813,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":194.79754166666663,"dec_deg":24.022277777777777,"epoch_ra_deg":195.125393,"epoch_dec_deg":23.87728,"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":"Coma Berenices","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ic-3958","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":16.71,"h_mag":12.88,"j_mag":13.76,"k_mag":12.57,"redshift":0.07332,"hubble_type":"E","redshift_cmb":0.07432584104998385,"ngc_type_code":"G","uncertainties":{"distance_ly":[46533506.933981776,46533506.933981776]},"major_axis_arcmin":0.53,"minor_axis_arcmin":0.4,"position_angle_deg":112,"surface_brightness":24.18,"radial_velocity_km_s":21177},"designations":[{"catalog":"2MASX","designation":"2MASX J12591138+2401199"},{"catalog":"IC","designation":"IC 3958"},{"catalog":"SDSS","designation":"SDSS J125911.40+240120.1"}],"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."}