{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.831","julian_year":2026.831,"time":"2026-10-31T08:34:18.709Z","years_from_j2000":26.831,"frame":"date","applied":"Proper motion, then precession and nutation. The catalogued position is carried along the great circle the object's own published motion puts it on, at a constant velocity, from the epoch that position was measured at, 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. The motion runs from position_epoch_jyear where the upstream publishes one — a timed pulsar's position belongs to the year it was timed — and from J2000 where it does not. 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-3639547","name":"PGC 3639547","class":"galaxy","category":"galaxy","object_type":"Galaxy","mag":19.91,"mag_band":"B","abs_mag":-14.46734415409124,"abs_mag_band":"B","distance_ly":244846954.2520222,"distance_method":"luminosity distance from a photometric redshift (GLADE+), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":37.9656,"dec_deg":-36.66753,"epoch_ra_deg":38.243783,"epoch_dec_deg":-36.547983,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"position_epoch_jyear":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Fornax","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/pgc-3639547","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)","attribution":"Dálya et al. 2022, MNRAS 514, 1403 (2022MNRAS.514.1403D) — \"Please cite this paper when using GLADE+ data\" — via VizieR VII/291. This research has made use of the VizieR catalogue access tool, CDS, Strasbourg, France (DOI: 10.26093/cds/vizier). The original description of the VizieR service was published in 2000, A&AS 143, 23.","commercial_use":"needs_permission"},"radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":19.91,"h_mag":12.095,"j_mag":12.818,"k_mag":11.954,"redshift":0.0164161282081,"redshift_cmb":0.0173014634440775,"uncertainties":{"distance_ly":[48079235.52757468,48299489.572650895],"stellar_mass_solar":[2802475735.9188833,2802475735.9188833]},"stellar_mass_solar":4670792893.198138},"designations":[{"catalog":"2MASX","designation":"2MASX 02315175-3640032"},{"catalog":"Other","designation":"2MASXJ02315175-3640032"},{"catalog":"PGC","designation":"PGC 3639547"}],"updated_at":"2026-10-01T09:42:28.932Z","citation":{"plain":"SpaceCatalog. PGC 3639547 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/pgc-3639547","bibtex":"@misc{spacecatalog_pgc-3639547,\n  author       = {{SpaceCatalog}},\n  title        = {{PGC 3639547}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/pgc-3639547},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from GLADE+ (Galaxy List for the Advanced Detector Era).}\n}","url":"https://spacecatalog.org/object/pgc-3639547","release":"DR1","doi":null},"references":[],"attribution":"Data from SpaceCatalog.org. Each record names its upstream in `source`, with that producer's terms in `source.license`, the acknowledgement it asks for in `source.attribution`, and whether its terms allow commercial use in `source.commercial_use`; those terms govern the record, and citing SpaceCatalog does not discharge them."}