In the Mauna Kea Observatories, which asteroid had the maximum radius?
select ?ent where { ?ent wdt:P31 wd:Q3863 . ?ent wdt:P2120 ?obj . ?ent wdt:P65 wd:Q831790 } ORDER BY DESC(?obj)LIMIT 5 
asteroid: Q3863 mauna kea observatories: Q831790