Discovered on December 2nd 2013, Nova Centauri 2013 is the brightest nova of the century thus far. Just after its peak, this photo shows just how easily visible it is with the naked-eye from a dark site.
Novae are binary systems where a hot, compact star called a white dwarf strips material away from a less evolved companion. This material builds up on the surface of the white dwarf until eventually there is enough to initiate nuclear fusion, this is a runaway process which results in an explosive event. During this process the nova increases in brightness by several magnitudes, occasionally becoming visible to the unaided eye - Nova Cen 2013 is one such case. As the explosion does not result in the destruction of either the white dwarf or its partner, some of these systems can return to accreting matter and erupt again as recurrent novae, so perhaps Nova Cen will go off again in the future!