Although not specifically searching for double stars, he did make a number of discoveries while testing his completed telescope objectives,[1] including Mu Herculis, 8 Sextantis, and 95 Ceti.[2] One of Clark's sons, Alvan Graham Clark, discovered the dim companion of Sirius. Two craters bear Clark Sr.'s name. The crater Clark on the Moon is jointly named for him and his son, Alvan Graham Clark, and one on Mars is named in his honour.[3] His other son was George Bassett Clark; both sons were partners in the firm.
Clark was also competitive in target shooting and received a patent for his device to allow bullets to be seated into a muzzle-loading rifle without damage to either the bullet or the rifle's muzzle. Exclusive license to this patent (1,565 of April 24, 1840) was made to Edwin Wesson, brother of Daniel B. Wesson.[4]