{"signature":{"version":"1.3","source":"NASA/JPL Small-Body Database (SBDB) API"},"phys_par":[{"title":"absolute magnitude","sigma":null,"ref":"E2025N01","units":null,"name":"H","desc":"absolute magnitude (magnitude at 1 au from Sun and observer)","value":"8.03","notes":"IRAS observations used: 24"},{"value":"171.71","notes":"IRAS observations used: 24","units":"km","name":"diameter","desc":"effective body diameter","ref":"IRAS-A-FPA-3-RDR-IMPS-V6.0","sigma":"3.1","title":"diameter"},{"value":"9.4146","notes":"REFERENCE LIST:[Zappala, V.; Scaltriti, F.; Di Martino, M. (1983) Icarus 56, 325-344.], [Michalowski, T. (1993) Icarus 106, 563-572.], [Behrend, R. (2003) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html], [Warner, B.D. (2007) Minor Planet Bull. 34, 104-107.], [Marciniak, A.; Michalowski, T.; Hirsch, R.; Polinska, K.; et al. (2009) Astron. Astrophys. 498, 313-320.], [Pilcher, F. (2010) Minor Planet Bull. 37, 119-122.], [Durech, J.; Kaasalainen, M.; Herald, D.; Dunham, D.; et al. (2011) Icarus 214, 652-670.], [Behrend, R. (2013) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html], [Behrend, R. (2017) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html], [Behrend, R. (2022) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html], [Mannucci, M.; Montigiani, N.; Gabellini, D.; Mortari, F. (2022) Minor Planet Bull. 49, 326-329.]","units":"h","name":"rot_per","desc":"body rotation period (synodic)","ref":"LCDB (Rev. 2023-October); Warner et al., 2009","sigma":null,"title":"rotation period"},{"ref":"IRAS-A-FPA-3-RDR-IMPS-V6.0","sigma":"0.002","title":"geometric albedo","notes":"IRAS observations used: 24","value":"0.0503","units":null,"name":"albedo","desc":"geometric albedo"},{"units":null,"name":"BV","desc":"color index B-V magnitude difference","value":"0.713","notes":"#obs=3; phase (min.=9.31, mean=9.48, max.=9.77) deg.","title":"B-V","ref":"EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2","sigma":"0.030"},{"ref":"EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2","sigma":"0.025","title":"U-B","value":"0.317","notes":"#obs=3; phase (min.=9.31, mean=9.48, max.=9.77) deg.","name":"UB","units":null,"desc":"color index U-B magnitude difference"},{"desc":"Tholen spectral taxonomic classification","name":"spec_T","units":null,"notes":"used 2 color indices; used ground-based radiometric albedo","value":"PC","title":"Tholen spectral type","sigma":null,"ref":"EAR-A-5-DDR-TAXONOMY-V4.0"},{"ref":"EAR-A-5-DDR-TAXONOMY-V4.0","sigma":null,"title":"SMASSII spectral type","notes":"based on a high-resolution spectrum by Xu et al. (1995) or Bus and Binzel (2002)","value":"C","name":"spec_B","units":null,"desc":"SMASSII spectral taxonomic classification"}],"object":{"pha":false,"kind":"an","prefix":null,"orbit_id":"141","fullname":"747 Winchester (A913 EK)","shortname":"747 Winchester","orbit_class":{"code":"MBA","name":"Main-belt Asteroid"},"neo":false,"spkid":"20000747","des":"747"},"orbit":{"data_arc":"41254","not_valid_after":null,"cov_epoch":"2457383.5","model_pars":[],"pe_used":"DE441","moid_jup":"1.89","comment":null,"n_obs_used":17750,"t_jup":"3.091","condition_code":"0","sb_used":"SB441-N16","moid":"1.08","rms":"0.22","n_dop_obs_used":null,"soln_date":"2026-06-05 03:59:52","not_valid_before":null,"producer":"Otto Matic","epoch":"2461200.5","source":"JPL","last_obs":"2026-02-18","orbit_id":"141","two_body":null,"n_del_obs_used":null,"first_obs":"1913-03-09","elements":[{"units":null,"name":"e","label":"e","title":"eccentricity","value":"0.34","sigma":"2.1e-09"},{"label":"a","title":"semi-major axis","name":"a","units":"au","value":"3","sigma":"2.5e-09"},{"sigma":"6.4e-09","value":"1.98","name":"q","units":"au","title":"perihelion distance","label":"q"},{"sigma":"1.4e-07","value":"18.2","label":"i","title":"inclination; angle with respect to x-y ecliptic plane","units":"deg","name":"i"},{"sigma":"4.4e-07","value":"129","title":"longitude of the ascending node","label":"node","units":"deg","name":"om"},{"sigma":"5.2e-07","value":"278","units":"deg","name":"w","title":"argument of perihelion","label":"peri"},{"sigma":"1.1e-06","value":"19.5","label":"M","title":"mean anomaly","units":"deg","name":"ma"},{"sigma":"5.6e-06","value":"2461097.906","name":"tp","units":"TDB","label":"tp","title":"time of perihelion passage"},{"name":"per","units":"d","title":"sidereal orbital period","label":"period","value":"1900","sigma":"2.4e-06"},{"value":"0.19","sigma":"2.4e-10","name":"n","units":"deg/d","label":"n","title":"mean motion"},{"label":"Q","title":"aphelion distance","units":"au","name":"ad","sigma":"3.4e-09","value":"4.02"}],"equinox":"J2000"}}