Comet Holmes, 2007-8
Copyright: Tunç Tezel
http://www.twanight.org/newTWAN/photos.asp?ID=3004106
17P/Holmes is normally a faint periodic comet. It was discovered by Edwin Holmes on 6th November 1892, because of a sudden increase in its magnitude, when it had brightened to an approximate magnitude of 4 or 5 before fading from visibility over a period of several weeks.
10 years ago, on 24th October 2007 to be exact, comet 17P/Holmes exploded into visibility once again after more than a century of dormancy. It became over half a million times brighter in a matter of hours, surprising astronomers and stargazers around the world. The outburst transformed it from an obscure and faint comet quietly orbiting the Sun with a period of about 7 years to a naked-eye object rivaling the brighter stars in the constellation Perseus.
In the weeks following the outburst, the comet faded as it swelled to become the biggest Solar system object, more than 5 times the size of the Sun. In the same interval, the resultant of movements of the Earth and comet in their respective orbits caused this huge retrograde loop in the rich starfields of Perseus. So, here is the picture of the incredible swelling-looping comet 17P/Holmes with its 2007-8 performance. And, below is the video: