{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.664","julian_year":2026.664,"time":"2026-08-31T14:11:49.073Z","years_from_j2000":26.664,"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-4644","name":"PGC 4644","class":"spiral_galaxy","category":"galaxy","object_type":"Spiral galaxy","mag":15.188,"mag_band":"B","abs_mag":-19.82151442686751,"abs_mag_band":"B","distance_ly":327588585.34296066,"distance_method":"luminosity distance from a photometric redshift (GLADE+), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":19.358641,"dec_deg":4.16871,"epoch_ra_deg":19.706152,"epoch_dec_deg":4.310341,"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":"Pisces","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/pgc-4644","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":15.188,"h_mag":13.693,"j_mag":14.264,"k_mag":13.463,"redshift":0.021281,"hubble_type":"3","redshift_cmb":0.0230498139037326,"uncertainties":{"distance_ly":[62915962.52881138,63283084.996951476],"stellar_mass_solar":[934124820.7406842,934124820.7406842]},"major_axis_arcmin":0.625153,"minor_axis_arcmin":0.346648,"morphology_source":"SIMBAD (2005ApJS..160..149S, quality D)","position_angle_deg":164,"stellar_mass_solar":2802374462.2220526},"designations":[{"catalog":"2MASX","designation":"2MASX 01172607+0410073"},{"catalog":"PGC","designation":"PGC 4644"},{"catalog":"WISExSCOS","designation":"WISExSCOS J011726.09+041006.6"}],"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":"2026-08-30T09:56:50.739Z","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."}