{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.687","julian_year":2026.687,"time":"2026-09-08T23:57:53.683Z","years_from_j2000":26.687,"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":"ugc-3138","name":"UGC 3138","class":"spiral_galaxy_sb","category":"galaxy","object_type":"Spiral galaxy Sb","mag":15.63,"mag_band":"B","abs_mag":-18.5246022585168,"abs_mag_band":"B","distance_ly":220976620.2425243,"distance_method":"luminosity distance from a spectroscopic redshift (GLADE+), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":70.7151,"dec_deg":18.55456,"epoch_ra_deg":71.106679,"epoch_dec_deg":18.605679,"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":"Taurus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ugc-3138","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":15.63,"h_mag":10.072,"j_mag":10.917,"k_mag":9.801,"redshift":0.01608,"hubble_type":"Sb","redshift_cmb":0.0156341356109276,"uncertainties":{"distance_ly":[14266999.851786233,14269130.023304708],"stellar_mass_solar":[5605010288.027545,5605010288.027545]},"major_axis_arcmin":0.977,"minor_axis_arcmin":0.449,"morphology_source":"SIMBAD (2003A&A...412...45P, quality E)","position_angle_deg":25,"stellar_mass_solar":42037577160.20659},"designations":[{"catalog":"2MASX","designation":"2MASX 04425162+1833164"},{"catalog":"PGC","designation":"PGC 15866"},{"catalog":"WISExSCOS","designation":"WISExSCOS J044251.61+183316.4"}],"source":{"id":"glade_plus","name":"GLADE+ (Galaxy List for the Advanced Detector Era)","url":"https://cdsarc.cds.unistra.fr/viz-bin/cat/VII/291","license":"VizieR terms; cite Dalya+ 2022 (2022MNRAS.514.1403D)"},"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."}