Chinese DR 21 Cited by user 凌雲 on 30 Jun 2025 DR 21是一個大分子雲. 它是唐斯(Downes)和萊因哈特(Rinehart)於1966年在星座天鵝座發現的連續電波源. DR 21位於距地球大約6000 ly處,延伸約80 ly.
English DR 21 Cited by user OtterAM on 18 Dec 2015 DR 21 is a huge molecular cloud located in the constellation of Cygnus. This area is located about 6,000 light-years away and extends for 80 light-years.