Robert Sheaffer wrote: >05:11:00 Eastbound Mag. 4 satellite, believed to be USA 129 > (#24680) moving just south of the keystone of > Hercules. Could you please fill me in which star is called "the keystone of Hercules" ? I can't find it in R.H. Allen's "Star Names". It may be an Americanism (like the "Big Dipper"), not known elsewhere. Regards, Bruno Tilgner 100533.2016@compuserve.com