Édouard Stephan discovered NGC 5644 = St XI-26, along with NGC 5647, on 11 Jun 1880. His position is accurate.

400/500mm - 17.5" (6/24/95): moderately bright, round, 1.0' diameter. Sharply concentrated with a well-defined, nearly stellar bright nucleus. Forms the vertex of a right angle with a mag 12 star 1.4' SW and a mag 14 star 0.9' NNW of center. Located 4.7' SSW of a mag 10 star. Forms a pair with NGC 5647 4.0' SE and brightest in a group.

Notes by Steve Gottlieb