▁magnitude ▁stars . ▁ ▁Thus ▁in ▁ 1 8 5 6 ▁Norman ▁P og son ▁of ▁Oxford ▁proposed ▁that ▁a ▁log arith mic ▁scale ▁of ▁▁ ≈ ▁ 2 . 5 1 2 ▁be ▁adopted ▁between ▁magn itudes , ▁so ▁five ▁magnitude ▁steps ▁correspond ed ▁precisely ▁to ▁a ▁factor ▁of ▁ 1 0 0 ▁in ▁bright ness . ▁Every ▁interval ▁of ▁one ▁magnitude ▁equ ates ▁to ▁a ▁variation ▁in ▁bright ness ▁of ▁ ▁or ▁roughly ▁ 2 . 5 1 2 ▁times . ▁Con sequently , ▁a ▁magnitude ▁ 1 ▁star ▁is ▁about ▁ 2 . 5 ▁times ▁br ighter ▁than ▁a ▁magnitude ▁ 2 ▁star , ▁ 2 . 5 2 ▁br ighter ▁than ▁a ▁magnitude ▁ 3 ▁star , ▁ 2 . 5 3 ▁br ighter ▁than ▁a ▁magnitude ▁ 4 ▁star , ▁and ▁so ▁on . ▁ ▁This ▁is ▁the ▁modern ▁magnitude ▁system , ▁which ▁measures ▁the ▁bright ness , ▁not ▁the ▁apparent ▁size , ▁of ▁stars . ▁Using ▁this ▁log arith mic ▁scale , ▁it ▁is ▁possible ▁for ▁a ▁star ▁to ▁be ▁br ighter ▁than ▁“ first ▁class ”, ▁so ▁Ar ct urus ▁or ▁V ega ▁are ▁magnitude ▁ 0 , ▁and ▁Si ri us ▁is ▁magnitude ▁− 1 . 4 6 . ▁ ▁Sc ale ▁▁ ▁As ▁mentioned ▁above , ▁the ▁scale ▁appears ▁to ▁work ▁' in ▁reverse ', ▁with ▁objects ▁with ▁a ▁negative ▁magnitude ▁being ▁br ighter ▁than ▁those ▁with ▁a ▁positive ▁magnitude . ▁The ▁more ▁negative ▁the ▁value , ▁the ▁br ighter ▁the ▁object . ▁