Finally! A question for a VSOer ...
It is aproximately 1600 light years away ...
The object in question is called V4641 Sgr ... meaning the stellar components vary in brightness. The black hole itself is not visible, however, the stellar components are! When it is at it's faintest, it is about magnitude 13.8, visible in a moderate sized telescope. I have observed it in a 33cm (13.1") dobsonian from light-polluted suburban skies. When it changes in brightness and undergoes what is called an "outburst", it can rise to magnitude 9.0+. This makes it easier to see in smaller instruments, however, it is not for the faint of heart. The star field is very rich and one needs very acurate star charts in order to correctly identify it.
The object was first identified as a bright x-ray object, it was some time later that it was also observed to varying in optical brightness as well and was added to several types of observing campaigns.
Charts of this object can be found at:
http://www.aavso.org/charts/SGR/V4641_SG…