{"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":"2026-09-02T15:57:48.006Z","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":"pgc-38631","name":"PGC 38631","class":"spiral_galaxy_sb","category":"galaxy","object_type":"Spiral galaxy Sb","mag":15.247,"mag_band":"B","abs_mag":-19.711035445880647,"abs_mag_band":"B","distance_ly":319913792.5607354,"distance_method":"luminosity distance from a spectroscopic redshift (GLADE+), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":182.36116,"dec_deg":40.831867,"epoch_ra_deg":182.70147,"epoch_dec_deg":40.682435,"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":"Canes Venatici","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/pgc-38631","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":15.247,"h_mag":12.316,"j_mag":13.056,"k_mag":12.045,"redshift":0.02323,"hubble_type":"Sb","redshift_cmb":0.0225186250161779,"uncertainties":{"distance_ly":[16876740.532678463,16882181.607092176],"stellar_mass_solar":[3736511724.726713,3736511724.726713]},"major_axis_arcmin":0.347,"minor_axis_arcmin":0.291,"morphology_source":"SIMBAD (2017MNRAS.471.4027B, quality E)","position_angle_deg":105,"stellar_mass_solar":8407151380.635104},"designations":[{"catalog":"2MASX","designation":"2MASX 12092667+4049547"},{"catalog":"PGC","designation":"PGC 38631"},{"catalog":"WISExSCOS","designation":"WISExSCOS J120926.71+404954.5"}],"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":"2026-09-01T22:58:55.274Z","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."}