{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.821","julian_year":2026.821,"time":"2026-10-27T19:55:42.349Z","years_from_j2000":26.821,"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":"ugc-6555","name":"UGC 6555","class":"galaxy","category":"galaxy","object_type":"Galaxy","mag":14.101,"mag_band":"B","abs_mag":-21.20664617658406,"abs_mag_band":"B","distance_ly":375798559.05259216,"distance_method":"luminosity distance from a spectroscopic redshift (GLADE+), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":173.749985,"dec_deg":51.218002,"epoch_ra_deg":174.117962,"epoch_dec_deg":51.068897,"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":"Ursa Major","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ugc-6555","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":14.101,"h_mag":10.722,"j_mag":11.424,"k_mag":10.413,"redshift":0.02697,"redshift_cmb":0.0263773031585443,"uncertainties":{"distance_ly":[20403888.755464446,20410939.821511008],"stellar_mass_solar":[7472842233.096267,7472842233.096267]},"stellar_mass_solar":61650948423.0442},"designations":[{"catalog":"2MASX","designation":"2MASX 11345999+5113048"},{"catalog":"WISExSCOS","designation":"WISExSCOS J113500.03+511304.7"}],"updated_at":"2026-10-01T09:42:28.932Z","citation":{"plain":"SpaceCatalog. UGC 6555 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ugc-6555","bibtex":"@misc{spacecatalog_ugc-6555,\n  author       = {{SpaceCatalog}},\n  title        = {{UGC 6555}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/ugc-6555},\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/ugc-6555","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."}