{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.664","julian_year":2026.664,"time":"2026-08-31T16:38:52.097Z","years_from_j2000":26.664,"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-3621","name":"IC 3621","class":"elliptical_galaxy_e","category":"galaxy","object_type":"Elliptical galaxy E","mag":15.65,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":1061708225.7098955,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":189.88991666666666,"dec_deg":15.502611111111111,"epoch_ra_deg":190.227314,"epoch_dec_deg":15.355047,"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-3621","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":15.65,"h_mag":11.46,"j_mag":12.23,"k_mag":11.27,"redshift":0.07101,"hubble_type":"E","wikidata_id":"Q3686573","redshift_cmb":0.07213948857519803,"ngc_type_code":"G","uncertainties":{"distance_ly":[45236257.71920728,45236257.71920728]},"major_axis_arcmin":1.01,"minor_axis_arcmin":0.75,"position_angle_deg":14,"surface_brightness":24.52,"radial_velocity_km_s":20534},"designations":[{"catalog":"2MASX","designation":"2MASX J12393357+1530091"},{"catalog":"IC","designation":"IC 3621"},{"catalog":"LEDA","designation":"LEDA 3090634"},{"catalog":"PGC","designation":"PGC 3090634"},{"catalog":"SDSS","designation":"SDSS J123933.58+153009.3"}],"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."}