NGC 6664 (also OCL 68) is a magnitude +7.8 open star cluster located 4,900 light-years away in the constellation Scutum.
The cluster was discovered by German-British astronomer William Herschel using a 47.5 cm (18.7 inch) f/13 speculum reflector at Datchet, Berkshire, on the 16th June 1784.
Spoiler
Right Ascension 18h 36m 30.6s, Declination -08° 11' 15"