{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.678","julian_year":2026.678,"time":"2026-09-05T15:28:35.002Z","years_from_j2000":26.678,"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":"ngc-5584","name":"NGC 5584","class":"intermediate_spiral_galaxy_sabc","category":"galaxy","object_type":"Intermediate spiral galaxy SABc","mag":12.77,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":89204346.95144352,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":215.59904166666666,"dec_deg":-0.3876666666666667,"epoch_ra_deg":215.943872,"epoch_dec_deg":-0.510333,"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":"Virgo","discovered":"1881","featured":false,"url":"https://spacecatalog.org/object/ngc-5584","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":12.77,"h_mag":10.05,"j_mag":10.84,"k_mag":9.95,"redshift":0.005525,"hubble_type":"SABc","wikidata_id":"Q956153","redshift_cmb":0.0063553591648479735,"discovered_by":"Edward Emerson Barnard","ngc_type_code":"G","uncertainties":{"distance_ly":[14498237.38726438,14498237.38726438]},"major_axis_arcmin":3.13,"minor_axis_arcmin":2.34,"wikipedia_article":"NGC 5584","position_angle_deg":154,"surface_brightness":23.71,"radial_velocity_km_s":1652},"designations":[{"catalog":"2MASX","designation":"2MASX J14222381-0023148"},{"catalog":"IRAS","designation":"IRAS 14198-0009"},{"catalog":"LEDA","designation":"LEDA 51344"},{"catalog":"MCG","designation":"MCG +00-37-001"},{"catalog":"NGC","designation":"NGC 5584"},{"catalog":"PGC","designation":"PGC 51344"},{"catalog":"SDSS","designation":"SDSS J142223.59-002318.2"},{"catalog":"SDSS","designation":"SDSS J142223.76-002315.5"},{"catalog":"SDSS","designation":"SDSS J142223.76-002315.6"},{"catalog":"SDSS","designation":"SDSS J142223.77-002315.6"},{"catalog":"UGC","designation":"UGC 9201"}],"source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0"},"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."}