{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.671","julian_year":2026.671,"time":"2026-09-03T02:31:06.734Z","years_from_j2000":26.671,"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-588","name":"IC 588","class":"spiral_galaxy_sa","category":"galaxy","object_type":"Spiral galaxy Sa","mag":14.25,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":349090639.1541414,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":150.52933333333334,"dec_deg":3.057694444444444,"epoch_ra_deg":150.877296,"epoch_dec_deg":2.928456,"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":"Sextans","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ic-588","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":15.08,"h_mag":11.41,"j_mag":12.04,"k_mag":11.06,"v_mag":14.25,"redshift":0.02335,"hubble_type":"Sa","wikidata_id":"Q3712009","redshift_cmb":0.02453586158365817,"ngc_type_code":"G","uncertainties":{"distance_ly":[20012199.309378922,20012199.309378922]},"major_axis_arcmin":0.9,"minor_axis_arcmin":0.53,"position_angle_deg":164,"surface_brightness":23.43,"radial_velocity_km_s":6918},"designations":[{"catalog":"2MASX","designation":"2MASX J10020701+0303277"},{"catalog":"IC","designation":"IC 588"},{"catalog":"IRAS","designation":"IRAS F09595+0318"},{"catalog":"LEDA","designation":"LEDA 29057"},{"catalog":"MCG","designation":"MCG +01-26-010"},{"catalog":"PGC","designation":"PGC 29057"},{"catalog":"SDSS","designation":"SDSS J100207.03+030327.6"},{"catalog":"SDSS","designation":"SDSS J100207.04+030327.6"},{"catalog":"SDSS","designation":"SDSS J100207.04+030327.7"},{"catalog":"UGC","designation":"UGC 5399"}],"source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-02T19:50:56.720Z","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."}