{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.664","julian_year":2026.664,"time":"2026-08-31T12:01:40.972Z","years_from_j2000":26.664,"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":"m1","name":"Crab Nebula","class":"supernova_remnant","category":"nebula","object_type":"Supernova remnant","mag":8.4,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":6500,"distance_method":"literature value (curated)","ra_deg":83.63320833333333,"dec_deg":22.01447222222222,"epoch_ra_deg":84.037181,"epoch_dec_deg":22.032832,"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":"Taurus","discovered":"1731","featured":true,"url":"https://spacecatalog.org/object/m1","radius_km":null,"radius_kind":null,"data_quality":null,"description":"The wreckage of a star that Chinese astronomers watched explode in 1054, bright enough then to be seen in daylight. At its heart a pulsar spins thirty times a second, lighting the whole nebula.","properties":{"v_mag":8.4,"wikidata_id":"Q10934","also_known_as":["Krab nebula","Taurus A"],"discovered_by":"John Bevis","ngc_type_code":"SNR","major_axis_arcmin":8,"minor_axis_arcmin":4,"wikipedia_article":"Crab Nebula"},"designations":[{"catalog":"Common name","designation":"Crab Nebula"},{"catalog":"IRAS","designation":"IRAS 05314+2200"},{"catalog":"IRAS","designation":"IRAS 05315+2158"},{"catalog":"LBN","designation":"LBN 833"},{"catalog":"Lynds","designation":"LBN 184.62-05.65"},{"catalog":"Messier","designation":"M 1"},{"catalog":"NGC","designation":"NGC 1952"}],"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."}