Comet 17-P-Holmes, from Hungary

Caption NASA:"A beautiful blue ion tail has become visible in deep telescopic images of Comet Holmes. Pointing generally away from the Sun and also planet Earth, the comet's ion tail is seriously foreshortened by our extreme viewing angle.
Still, enthusiastic comet watchers have remarked that on the whole, the compact but tentacled appearance suggests a jellyfish or even a "cosmic calamaro".
This stunning view of the comet's greenish coma and blue tail was recorded on November 4, 2007, in clear skies near Budapest, Hungary.
The colors are caused by molecules in the tenuous gas, like C2 (green) and CO+ (blue), fluorescing in sunlight".