▁two ▁functions ▁the ▁first ▁being ▁to ▁provide ▁a ▁means ▁( ind icator ) ▁to ▁reading ▁the ▁angular ▁orientation ▁of ▁the ▁instrument , ▁the ▁second ▁function ▁ens uring ▁that ▁the ▁instrument ▁when ▁opt ically ▁aligned ▁with ▁the ▁object ▁of ▁interest ▁is ▁situated ▁parallel ▁with ▁the ▁vertical ▁plane ▁( per pend icular ▁with ▁the ▁ground ). ▁ ▁It ▁has ▁been ▁stated ▁by ▁non ▁astronom ers ▁and ▁non ▁navig ators , ▁that ▁two ▁people ▁are ▁required ▁to ▁use ▁the ▁small ▁instrument ▁successfully ; ▁one ▁to ▁take ▁the ▁sight ▁and ▁one ▁to ▁read ▁the ▁cord ▁( pl um ▁line ) ▁position ▁on ▁the ▁radius ▁segment ▁and ▁incorrect ▁pres umption ▁as ▁the ▁instrument ▁is ▁to ▁be ▁held ▁flush ▁( face ▁on ) ▁and ▁below ▁eye ▁level ▁with ▁a ▁single ▁user , ▁the ▁two ▁holes ▁used ▁for ▁project ing ▁the ▁image ▁of ▁the ▁Sun ▁not ▁direct ▁sight ing . ▁ ▁As ▁one ▁can ▁see ▁from ▁the ▁photograph , ▁it ▁is ▁easy ▁to ▁opt ically ▁aligned ▁the ▁instrument ▁with ▁the ▁Sun ▁using ▁simple ▁image ▁projection ▁method , ▁the ▁device ▁held ▁in ▁a ▁single ▁hand . ▁ ▁At ▁the ▁moment ▁of ▁alignment , ▁one ▁views ▁the ▁face ▁of ▁the ▁instrument ▁to ▁read ▁the ▁angular ▁position ▁of ▁the ▁cord ▁relative ▁to ▁the ▁rad ii ▁segment ▁of ▁the ▁instrument . ▁ ▁However , ▁it ▁does ▁help ▁to ▁have ▁another ▁person ▁write ▁down ▁the ▁scale ▁read ings ▁as ▁they ▁are ▁taken ▁if ▁a ▁single ▁operator ▁is ▁not ▁able ▁to ▁do ▁such ▁because ▁of ▁environmental ▁conditions , ▁the ▁single ▁operator ▁not ▁having ▁the ▁cap ability