{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.663","julian_year":2026.663,"time":"2026-08-31T06:45:22.864Z","years_from_j2000":26.663,"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-4172","name":"IC 4172","class":"spiral_galaxy_sb","category":"galaxy","object_type":"Spiral galaxy Sb","mag":16.21,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":510972724.8876918,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":196.639,"dec_deg":22.85038888888889,"epoch_ra_deg":196.965759,"epoch_dec_deg":22.706644,"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-4172","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":16.21,"h_mag":13.06,"j_mag":13.91,"k_mag":12.88,"redshift":0.03466,"hubble_type":"Sb","wikidata_id":"Q3683796","redshift_cmb":0.03562421590560083,"ngc_type_code":"G","uncertainties":{"distance_ly":[25094949.91466952,25094949.91466952]},"major_axis_arcmin":0.49,"minor_axis_arcmin":0.39,"position_angle_deg":85,"surface_brightness":23.41,"radial_velocity_km_s":10211},"designations":[{"catalog":"2MASX","designation":"2MASX J13063328+2251010"},{"catalog":"IC","designation":"IC 4172"},{"catalog":"LEDA","designation":"LEDA 45379"},{"catalog":"PGC","designation":"PGC 45379"},{"catalog":"SDSS","designation":"SDSS J130633.35+225101.3"},{"catalog":"SDSS","designation":"SDSS J130633.35+225101.4"}],"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."}