{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.675","julian_year":2026.675,"time":"2026-09-04T14:39:40.379Z","years_from_j2000":26.675,"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-2155947","name":"PGC 2155947","class":"galaxy","category":"galaxy","object_type":"Galaxy","mag":18.17,"mag_band":"B","abs_mag":-16.584189129831906,"abs_mag_band":"B","distance_ly":291248502.58648264,"distance_method":"luminosity distance from a photometric redshift (GLADE+), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":218.774,"dec_deg":39.80619,"epoch_ra_deg":219.041493,"epoch_dec_deg":39.688407,"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":"Boötes","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/pgc-2155947","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":18.17,"redshift":0.0202927301464,"redshift_cmb":0.0205310333086493,"uncertainties":{"distance_ly":[59497685.70059143,59834054.16427853],"stellar_mass_solar":[93413960.42877375,93413960.42877375]},"stellar_mass_solar":186827920.8575475},"designations":[{"catalog":"PGC","designation":"PGC 2155947"},{"catalog":"WISExSCOS","designation":"WISExSCOS J143505.94+394821.8"}],"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."}