{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.654","julian_year":2026.654,"time":"2026-08-27T17:42:15.963Z","years_from_j2000":26.654,"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":"m20","name":"Trifid Nebula","class":"nebula","category":"nebula","object_type":"Nebula","mag":8.5,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":4100,"distance_method":"literature value (curated)","ra_deg":270.6754583333333,"dec_deg":-22.971888888888888,"epoch_ra_deg":271.082758,"epoch_dec_deg":-22.971907,"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":"Sagittarius","discovered":"1764","featured":true,"url":"https://spacecatalog.org/object/m20","radius_km":null,"radius_kind":null,"data_quality":null,"description":"A rare combination in one object: red emission nebula, blue reflection nebula, and the dark dust lanes that cut it into three.","properties":{"b_mag":6.3,"v_mag":8.5,"redshift":-0.000017,"wikidata_id":"Q11377","discovered_by":"Charles Messier","ngc_type_code":"Neb","major_axis_arcmin":28,"minor_axis_arcmin":28,"wikipedia_article":"Trifid Nebula","radial_velocity_km_s":-5},"designations":[{"catalog":"Barnard","designation":"Barnard 85"},{"catalog":"Common name","designation":"Trifid Nebula"},{"catalog":"IAU cluster","designation":"C 1759-230"},{"catalog":"LBN","designation":"LBN 27"},{"catalog":"Lynds","designation":"LBN 006.99-00.17"},{"catalog":"Messier","designation":"M 20"},{"catalog":"MWSC","designation":"MWSC 2789"},{"catalog":"NGC","designation":"NGC 6514"}],"source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-27T16:03:54.983Z","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."}