▁par abol ic ▁path ▁from ▁three ▁observations . ▁This ▁was ▁used ▁by ▁Edmund ▁Hal ley ▁to ▁establish ▁the ▁or bits ▁of ▁various ▁com ets , ▁including ▁that ▁which ▁be ars ▁his ▁name . ▁Newton ' s ▁method ▁of ▁success ive ▁approximation ▁was ▁formal ised ▁into ▁an ▁analyt ic ▁method ▁by ▁E uler ▁in ▁ 1 7 4 4 , ▁whose ▁work ▁was ▁in ▁turn ▁general ised ▁to ▁elli pt ical ▁and ▁hyper bol ic ▁or bits ▁by ▁Lam bert ▁in ▁ 1 7 6 1 – 1 7 7 7 . ▁ ▁Another ▁mil estone ▁in ▁orbit ▁determ ination ▁was ▁Carl ▁Friedrich ▁G auss ' ▁assistance ▁in ▁the ▁" rec overy " ▁of ▁the ▁d war f ▁planet ▁Cer es ▁in ▁ 1 8 0 1 . ▁ ▁G auss ' s ▁method ▁was ▁able ▁to ▁use ▁just ▁three ▁observations ▁( in ▁the ▁form ▁of ▁cel est ial ▁coordinates ) ▁to ▁find ▁the ▁six ▁orb ital ▁elements ▁that ▁completely ▁describe ▁an ▁orbit . ▁ ▁The ▁theory ▁of ▁orbit ▁determ ination ▁has ▁subsequently ▁been ▁developed ▁to ▁the ▁point ▁where ▁today ▁it ▁is ▁applied ▁in ▁G PS ▁rece ivers ▁as ▁well ▁as ▁the ▁tracking ▁and ▁catalog uing ▁of ▁newly ▁observed ▁minor ▁plan ets . ▁ ▁Observ ational ▁data ▁In ▁order ▁to ▁determine ▁the ▁unknown ▁orbit ▁of ▁a ▁body , ▁some ▁observations ▁of ▁its ▁motion ▁with ▁time ▁are ▁required . ▁In ▁early ▁modern ▁astronom y , ▁the ▁only ▁available ▁observ ational ▁data ▁for ▁cel est ial ▁objects ▁were ▁the ▁right ▁asc ension ▁and ▁decl ination ,