{"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":"2026-09-02T14:43:34.630Z","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-21","name":"IC 21","class":"barred_spiral_galaxy_sbb","category":"galaxy","object_type":"Barred spiral galaxy SBb","mag":15.54,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":869039770.1834044,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":7.293458333333334,"dec_deg":-0.16377777777777777,"epoch_ra_deg":7.637446,"epoch_dec_deg":-0.01527,"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":"Cetus","discovered":"1891","featured":false,"url":"https://spacecatalog.org/object/ic-21","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":15.54,"h_mag":12.42,"j_mag":13.05,"k_mag":12.11,"redshift":0.06079,"hubble_type":"SBb","wikidata_id":"Q3715767","redshift_cmb":0.059564868233836776,"discovered_by":"Stéphane Javelle","ngc_type_code":"G","uncertainties":{"distance_ly":[37932169.25118764,37932169.25118764]},"major_axis_arcmin":0.49,"minor_axis_arcmin":0.45,"position_angle_deg":6,"surface_brightness":22.96,"radial_velocity_km_s":17671},"designations":[{"catalog":"2MASX","designation":"2MASX J00291043-0009490"},{"catalog":"IC","designation":"IC 21"},{"catalog":"LEDA","designation":"LEDA 1785"},{"catalog":"MCG","designation":"MCG +00-02-053"},{"catalog":"PGC","designation":"PGC 1785"},{"catalog":"SDSS","designation":"SDSS J002910.42-000949.5"},{"catalog":"SDSS","designation":"SDSS J002910.42-000949.6"}],"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."}