▁And ▁there ▁are ▁some ▁Stars ▁of ▁such ▁an ▁inter med ial ▁Order , ▁that ▁the ▁Astronom ers ▁have ▁differ ed ▁in ▁class ing ▁of ▁them ; ▁some ▁putting ▁the ▁same ▁Stars ▁in ▁one ▁Class , ▁others ▁in ▁another . ▁For ▁Example : ▁The ▁little ▁Dog ▁was ▁by ▁Ty cho ▁placed ▁among ▁the ▁Stars ▁of ▁the ▁second ▁Magn itude , ▁which ▁P to le my ▁reck oned ▁among ▁the ▁Stars ▁of ▁the ▁first ▁Class : ▁And ▁therefore ▁it ▁is ▁not ▁truly ▁either ▁of ▁the ▁first ▁or ▁second ▁Order , ▁but ▁ought ▁to ▁be ▁ranked ▁in ▁a ▁Place ▁between ▁both . ▁Note ▁that ▁the ▁br ighter ▁the ▁star , ▁the ▁smaller ▁the ▁magnitude : ▁Bright ▁" first ▁magnitude " ▁stars ▁are ▁" 1 st - class " ▁stars , ▁while ▁stars ▁bare ly ▁visible ▁to ▁the ▁n aked ▁eye ▁are ▁" six th ▁magnitude " ▁or ▁" 6 th - class ". ▁The ▁system ▁was ▁a ▁simple ▁del ine ation ▁of ▁stell ar ▁bright ness ▁into ▁six ▁distinct ▁groups ▁but ▁made ▁no ▁allow ance ▁for ▁the ▁variations ▁in ▁bright ness ▁within ▁a ▁group . ▁ ▁Ty cho ▁Bra he ▁attempted ▁to ▁directly ▁measure ▁the ▁" b ign ess " ▁of ▁the ▁stars ▁in ▁terms ▁of ▁angular ▁size , ▁which ▁in ▁theory ▁meant ▁that ▁a ▁star ' s ▁magnitude ▁could ▁be ▁determined ▁by ▁more ▁than ▁just ▁the ▁subject ive ▁judgment ▁described ▁in ▁the ▁above ▁quote . ▁He ▁concluded ▁that ▁first ▁magnitude ▁stars ▁measured ▁ 2 ▁arc ▁minutes ▁( 2 ′ ) ▁in ▁apparent ▁diameter ▁( ▁of