{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.663","julian_year":2026.663,"time":"2026-08-31T06:44:21.296Z","years_from_j2000":26.663,"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":"m84","name":"M84","class":"elliptical_galaxy_e","category":"galaxy","object_type":"Elliptical galaxy E","mag":9.79,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":61294749.39183808,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":186.26558333333332,"dec_deg":12.886972222222221,"epoch_ra_deg":186.606265,"epoch_dec_deg":12.7382,"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":"1781","featured":false,"url":"https://spacecatalog.org/object/m84","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":10.01,"h_mag":6.47,"j_mag":7.12,"k_mag":6.22,"v_mag":9.79,"redshift":0.00327,"hubble_type":"E","wikidata_id":"Q92258118","redshift_cmb":0.004373501283379433,"discovered_by":"Charles Messier","ngc_type_code":"G","uncertainties":{"distance_ly":[14240455.061305562,14240455.061305562]},"major_axis_arcmin":7.41,"minor_axis_arcmin":6.44,"wikipedia_article":"Messier 84","position_angle_deg":133,"surface_brightness":23.23,"radial_velocity_km_s":979},"designations":[{"catalog":"2MASX","designation":"2MASX J12250377+1253130"},{"catalog":"HD","designation":"HD 108091"},{"catalog":"IRAS","designation":"IRAS 12224+1309"},{"catalog":"IRAS","designation":"IRAS F12225+1309"},{"catalog":"LEDA","designation":"LEDA 40455"},{"catalog":"MCG","designation":"MCG +02-32-034"},{"catalog":"Messier","designation":"M 84"},{"catalog":"NGC","designation":"NGC 4374"},{"catalog":"PGC","designation":"PGC 40455"},{"catalog":"SDSS","designation":"SDSS J122503.74+125312.8"},{"catalog":"UGC","designation":"UGC 7494"}],"source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-30T09:56:50.739Z","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."}