First time I seen this, both visually and photographically. Couldn't have found it without my EQ5Pro due to the light pollution in suburban Sydney.
NGC5139 is also known as Omega Centauri, and it is a globular cluster - stars orbiting a galactic core, strongly bound together by gravity resulting in a spherical shape.
10x30s unguided, didn't really manage to pull it off.
Canon 1000D, SW102x500, prime focus, 10x30s @ ISO 400.