{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.681","julian_year":2026.681,"time":"2026-09-06T13:22:21.954Z","years_from_j2000":26.681,"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":"ngc-4139","name":"NGC 4139","class":"lenticular_galaxy_s0","category":"galaxy","object_type":"Lenticular galaxy S0","mag":14.72,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":282007723.4277878,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":181.14179166666668,"dec_deg":1.801611111111111,"epoch_ra_deg":181.485967,"epoch_dec_deg":1.652038,"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":"Virgo","discovered":"1863","featured":false,"url":"https://spacecatalog.org/object/ngc-4139","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":14.72,"h_mag":10.9,"j_mag":11.51,"k_mag":10.62,"redshift":0.01868,"hubble_type":"S0","wikidata_id":"Q1109246","redshift_cmb":0.01988907750205504,"discovered_by":"Heinrich Louis d'Arrest","ngc_type_code":"G","uncertainties":{"distance_ly":[18176711.87566838,18176711.87566838]},"major_axis_arcmin":1.2,"minor_axis_arcmin":0.48,"position_angle_deg":159,"surface_brightness":23.87,"radial_velocity_km_s":5548},"designations":[{"catalog":"2MASX","designation":"2MASX J12043399+0148056"},{"catalog":"IC","designation":"IC 2989"},{"catalog":"LEDA","designation":"LEDA 38213"},{"catalog":"MCG","designation":"MCG +00-31-030"},{"catalog":"NGC","designation":"NGC 4139"},{"catalog":"PGC","designation":"PGC 38213"},{"catalog":"SDSS","designation":"SDSS J120434.02+014805.7"},{"catalog":"SDSS","designation":"SDSS J120434.03+014805.7"},{"catalog":"SDSS","designation":"SDSS J120434.03+014805.8"}],"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."}