Bruce Murray Space Image LibraryMESSENGER observes comet 2P/Encke MESSENGER observes comet 2P/Encke MESSENGER observed comet Encke from its unique perspective in November and December 2013. On November 17, 2013, 2P/Encke made its closest approach to Mercury, about 3.7 million kilometers) from MESSENGER and 52.6 million kilometers from the Sun. The image has been smoothed to enhance the faint tail of the comet. The tail was oriented nearly side on to MESSENGER in this image and is seen to stretch several degrees from the comet's bright coma in the direction away from the Sun. NASA / JHUAPL / CIWOriginally posted on the MESSENGER website.See also this image from the MESSENGER website of the first detection of comet Encke.And this companion image of comet ISON from November 20, 2013.Here is an animation showing the viewing geometry of MESSENGER's observations of Encke and ISON.