As promised, as Comet ISON nears its closest approach to the Sun (called perihelion) on November 28, it is gaining the attention of NASA's solar observatories. First up is the Solar Terrestrial Relations Observatory (STEREO), which captured ISON and periodic comet 2P/Encke in its HI-1 camera November 21. In the time-lapse video below, dark ripples coming from the right side are more dense areas in the solar wind, causing ripples in Comet Encke's tail.
The most intriguing solar observatory images, though, likely will come from NASA's Solar and Heliospheric Observatory (SOHO). On the evening of the 26th Eastern time, ISON will enter the field of view of SOHO’s LASCO C3, a wide-field coronagraph that blocks the Sun’s disk and allows views of the solar corona and other nearby interesting things (such as comets), and will remain visible to it for nearly four days. On the day of perihelion, the comet will be visible in the narrower field of the LASCO C2 coronagraph and will stay there for about 10 hours. You can access these images at sohowww.nascom.nasa.gov/data/realtime-images.html.
For more professional images of this special celestial visitor, visit NASA's Comet ISON Image Gallery, and for complete coverage and observing information, check out www.Astronomy.com/ISON.
Credit: Karl Battams/NASA/STEREO/CIOC