Comet ISON Appears Still Intact
On November 21 Comet C/2012 S1, ISON entered the field of view of the HI-1 camera on NASA’s Solar Terrestrial Relations Observatory (STEREO) appearing to still be intact. NASA’s twin STEREO probes, which are designed to observe the sun, can see sun-diving comets even when the glare becomes intense. The above image shows Comet ISON joining Earth, Mercury, and Comet Encke in the field of view of STEREO-A’s Heliospheric Imager. (Comet Encke is a periodic comet which completes its orbit of the Sun once every three years, the shortest period of any known comet.)
Comet ISON’s grand entrance!
‘The dark ‘clouds’ of stuff you see coming from the right are density enhancements in the solar wind, and these are what are causing all the ripples you see in comet Encke’s tail,‘ explains Karl Battams of NASA’s Comet ISON Observing Campaign (CIOC).‘I can pretty much promise you that we’re going to see ISON’s tail doing that in a couple of day’s time, but on a much larger scale!’
Battams also points out that Comet Encke and Comet ISON are converging for a photogenic close encounter. ‘No they’re not going to hit each other, in reality they are millions of miles apart, but as seen from the STEREO-A spacecraft, they are going to get very close! We are probably a couple of days away from seeing two comets almost side-by-side in that camera, with long tails flowing behind them in the solar wind. To say that such an image will be unprecedented is rather an understatement.’
WOW!! To recap – Comet ISON is still plunging toward the Sun and brightening as it heads for its perilous close encounter on November 28th. Because the comet is moving into the glow of dawn, it will soon be impossible for cameras here on Earth to track it. Fortunately, however, NASA’s fleet of solar spacecraft are able to follow the comet into the glare. In the next few days STEREO-B, the Solar & Heliospheric Observatory (SOHO), and the Solar Dynamics Observatory (SDO) will join the hunt, providing continuous views all the way to ISON’s perihelion, or closest approach to the sun, on Thanksgiving Day. If ISON survives this encounter it should put on a nice show during the first week of December!
Above Image Credits: NASA’s Goddard Space Flight Center/STEREO/Karl Battams/CIOC
Comet ISON shows off its tail in the above three-minute exposure taken on November 19, 2013 at 6:10 am EST, using a 14-inch telescope located at the Marshall Space Flight Center. The star images are trailed because the telescope is tracking on the comet, which is now exhibiting obvious motion with respect to the background stars over a period of minutes. At the time of this image, Comet ISON was some 44 million miles from the sun, 80 million miles from Earth, moving at a speed of 136,700 miles per hour.