R.J. Mitchell probably discovered IC 3669, along with IC 3668, during an observation of NGC 4618. On 10 Apr 1855, he wrote, "The s branch is patchy, having 2 B spots near p end." Three nights later he added "Seen as before, I susp a * in the f of the 2 knots in s branch." A later observation in 1868 by C.E. Burton also noted, "The s end of annulus suspected to have two B patches in it.; S st inv." Max Wolf independently discovered IC 3669 = W. V-3 on a Heidelberg plate taken 21 Mar 1903. Wolf is credited with the discovery in the IC.

900/1200mm - 48" (4/7/13): IC 3669 is a brighter arc or section of the single broad arm on the southeast side about 1' SE of the core of NGC 4618.

Notes by Steve Gottlieb