{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.673","julian_year":2026.673,"time":"2026-09-03T23:09:39.011Z","years_from_j2000":26.673,"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-1864","name":"NGC 1864","class":"open_cluster","category":"cluster","object_type":"Open cluster","mag":12.86,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":null,"distance_method":null,"ra_deg":78.16916666666667,"dec_deg":-67.62124999999999,"epoch_ra_deg":78.159292,"epoch_dec_deg":-67.588343,"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":"Dorado","discovered":"1834","featured":false,"url":"https://spacecatalog.org/object/ngc-1864","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":13.05,"v_mag":12.86,"wikidata_id":"Q1045760","discovered_by":"John Frederick William Herschel","ngc_type_code":"OCl","major_axis_arcmin":1.1,"minor_axis_arcmin":0.95,"position_angle_deg":110},"designations":[{"catalog":"ESO","designation":"ESO 056-079"},{"catalog":"ESO","designation":"ESO 56-79"},{"catalog":"NGC","designation":"NGC 1864"}],"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."}