This globular cluster was discovered by Messier in 1746.
Approximately 30,000 light-years from earth, this cluster contains
several hundreds of thousands stars. Apparent magnitude of +7.6
and can easily be seen with binoculars.
There are over 70 variable stars in this cluster, not too shaby for
Ophiuchus. In 1938 a nova appeared, however, astronomers did not
discovered it until 1964 when the plates were examined.
(embarassing) The nova reached a max brightness of magnitude +9.2
over five times brighter than the brightest regular star in the cluster
and would have put on a good show.