Comet ISON (IMAGE) NASA/Goddard Space Flight Center Caption Comet ISON entered the view of NASA's Solar Terrestrial Relations Observatory on Nov. 21, 2013, where it can be seen with Earth, Mercury and comet 2P/Encke. Four NASA solar observatories will watch ISON on Thanksgiving week until it slingshots around the sun on Nov. 28, 2013. Credit Karl Battams/NASA/STEREO/CIOC Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.