John Herschel discovered NGC 1731 = h2691 on 23 Dec 1834 and described "a double star, the chief of a pretty rich, pretty large cluster of loosely scattered stars, little compressed to the middle; 8'; stars 11..15th mag." On a second sweep he called it "a poor loose cluster 8' diameter, stars 10..15th mag, chief double star taken." and on his third and last sweep, "a double star, the chief of a poor loose cluster 3 or 4' diameter."

400/500mm - 18" (7/9/02 - Magellan Observatory, Australia): at 128x this is a large region of nebulosity (LHa 120-N4, a confirmed supernova remnant) and scattered stars (association LH 4), 6'-7' diameter. The double star h3710 = 10.7/12.7 at 12" is involved on the east side, along with a number of fainter stars.

Notes by Steve Gottlieb