{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.777","julian_year":2026.777,"time":"2026-10-11T23:27:03.583Z","years_from_j2000":26.777,"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":"m42","name":"Great Orion Nebula","class":"nebula_with_cluster","category":"nebula","object_type":"Nebula with cluster","mag":4,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":1344,"distance_method":"literature value (curated)","ra_deg":83.81866666666666,"dec_deg":-5.389666666666667,"epoch_ra_deg":84.149754,"epoch_dec_deg":-5.371695,"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":"Orion","discovered":"1610","featured":true,"url":"https://spacecatalog.org/object/m42","source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0","attribution":"OpenNGC, Mattia Verga (github.com/mattiaverga/OpenNGC). Fields derived from it stay under CC BY-SA 4.0.","commercial_use":"allowed"},"radius_km":null,"radius_kind":null,"data_quality":null,"description":"The nearest stellar nursery — a glowing cloud where a thousand new stars are igniting, visible to the naked eye as the middle \"star\" of Orion's sword.","properties":{"b_mag":4,"v_mag":4,"redshift":0.000093,"wikidata_id":"Q13903","also_known_as":["Great Nebula in Orion"],"discovered_by":"Nicolas-Claude Fabri de Peiresc","ngc_type_code":"Cl+N","major_axis_arcmin":90,"minor_axis_arcmin":60,"wikipedia_article":"Orion Nebula","radial_velocity_km_s":28},"designations":[{"catalog":"Common name","designation":"Great Orion Nebula"},{"catalog":"Common name","designation":"Orion Nebula"},{"catalog":"LBN","designation":"LBN 974"},{"catalog":"Lynds","designation":"LBN 209.13-19.35"},{"catalog":"Messier","designation":"M 42"},{"catalog":"MWSC","designation":"MWSC 582"},{"catalog":"NGC","designation":"NGC 1976"}],"updated_at":"2026-10-01T09:42:28.932Z","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."}