{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.686","julian_year":2026.686,"time":"2026-09-08T15:50:29.928Z","years_from_j2000":26.686,"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":"ugc-5998","name":"UGC 5998","class":"spiral_galaxy_sm","category":"galaxy","object_type":"Spiral galaxy Sm","mag":14.3,"mag_band":"B","abs_mag":-17.833786329485438,"abs_mag_band":"B","distance_ly":87133095.09955356,"distance_method":"luminosity distance from a photometric redshift (GLADE+), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":163.285,"dec_deg":50.28453,"epoch_ra_deg":163.683034,"epoch_dec_deg":50.141762,"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":"Ursa Major","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ugc-5998","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":14.3,"h_mag":13.463,"j_mag":13.776,"k_mag":12.969,"redshift":0.00537558268779,"hubble_type":"Sm","redshift_cmb":0.0062084826045565,"uncertainties":{"distance_ly":[16112277.334082901,16135299.13268779],"stellar_mass_solar":[93422380.6854519,93422380.6854519]},"major_axis_arcmin":1.25358,"minor_axis_arcmin":0.481627,"morphology_source":"SIMBAD (2015ApJS..217...27A, quality C)","position_angle_deg":108,"stellar_mass_solar":186844761.3709038},"designations":[{"catalog":"2MASX","designation":"2MASX 10530843+5017053"},{"catalog":"PGC","designation":"PGC 32678"}],"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."}