John Herschel discovered NGC 4661 = h3415 on 5 Jun 1834 and logged "F; R; pL; gbM.". His position was not measured accurately - the RA is given to the nearest minute of time and the RA to the nearest min of arc and marked "+/-". There is nothing at his rough position, though 16' north is ESO 322-072 = PGC 42983, often referred to as NGC 4650B in the literature. The letter designation originated in the RC2. Corwin notes that ESO 322-072 is the only reasonably candidate for NGC 4661, so the identification is fairly certain.

600/800mm - 24" (4/12/08 - Magellan Observatory, Australia): at 200x this Centaurus cluster member (AGC 3526) was moderately bright, fairly small, elongated 2:1 WNW-ESE, 0.8'x0.4'. Located just 1' S of a 45" pair of mag 12.5 stars and 11.7' SE of NGC 4661.

Notes by Steve Gottlieb