▁spir al ▁galax y ▁located ▁in ▁the ▁const ell ation ▁Vir go . ▁It ▁is ▁located ▁at ▁a ▁distance ▁of ▁circa ▁ 1 4 0 ▁million ▁light ▁years ▁from ▁Earth , ▁which , ▁given ▁its ▁apparent ▁dimensions , ▁means ▁that ▁NGC ▁ 5 4 6 8 ▁is ▁about ▁ 1 1 0 , 0 0 0 ▁light ▁years ▁across . ▁It ▁was ▁discovered ▁by ▁William ▁H ersch el ▁on ▁March ▁ 5 , ▁ 1 7 8 5 . ▁ ▁NGC ▁ 5 4 6 8 ▁has ▁been ▁home ▁to ▁ 5 ▁super nov ae ▁in ▁the ▁last ▁ 2 0 ▁years , ▁SN ▁ 1 9 9 9 cp ▁( type ▁I a , ▁mag . ▁ 1 8 . 2 ), ▁SN ▁ 2 0 0 2 cr ▁( type ▁I a , ▁mag . ▁ 1 6 . 5 ), ▁SN ▁ 2 0 0 2 ed ▁( type ▁II P , ▁mag ▁ 1 6 . 5 ), ▁SN ▁ 2 0 0 5 P ▁( type ▁I a - pec , ▁mag ▁ 1 8 . 1 ), ▁and ▁SN ▁ 2 0 1 8 df g ▁( type ▁II b ). ▁NGC ▁ 5 4 6 8 ▁is ▁seen ▁face - on . ▁The ▁spir al ▁pattern ▁is ▁open . ▁The ▁two ▁principal ▁arms ▁em an ate ▁from ▁a ▁small ▁bar ▁and ▁start ▁to ▁branch ▁into ▁several ▁thin ▁fragments ▁after ▁a ▁half ▁the ▁one ▁and ▁a ▁quarter ▁revolution ▁the ▁other . ▁In ▁the ▁images ▁of ▁the ▁Car