ISON Image of the Week

What a Difference a Few Days Can Make!  (Nov 18, 2013)

On November 13, Gregg Ruppel (Ellisville, MO, USA) recorded this lovely image of comet ISON. We did not expect what ISON had planned for us! [Credit: Gregg Ruppel via]
This week we spoil you with two images instead of one, and we do this as Comet C/2012 S1 (ISON) has spoiled us by suddenly taking a turn for the spectacular!

Just a few days ago, on November 13, 2013, we were smiling happily as numerous beautiful images of comet ISON were being posted online. The image opposite, from Missouri-based Gregg Ruppel, was typical of what we were seeing: a green fuzzy coma and the beginnings of new structures in the tail of the comet. Reported magnitudes were of the order of +8 to +7, making ISON visible to most people in binoculars. We speculated that by the end of the week there might be one or two naked-eye observations of the comet if it were to brighten the way we predict. The nucleus was in tact, and we were optimistic that ISON would at least reach perihelion as a reasonably bright comet.

However, amongst ourselves (the CIOC Team) we had commented that if ISON were to obtain the negative magnitudes at perihelion that we originally felt it would, then it really needed to put some work in and start brightening up fast. If anything, we were perhaps a little concerned about the comet.

Clearly our concern was misplaced.

During the day on November 13, we began to read reports that ISON may have started to do something different, with a noticeable brightening and increased rates of dust and gas production. Over the following 48 hours, these reports increased and a flood of images began to arrive showing a comet that was clearly in outburst.

By November 15, there was no doubt that ISON was beginning to wake up. The question that came immediately to mind was whether ISON was simply beginning to live up to its lofty expectations, or if something catastrophic had occurred and this outburst signaled the beginning of the end. We still have no answer to this question and we may not find out until ISON reaches the field of view of the NASA STEREO spacecraft on November 21, 2013. Until then we encourage everyone to make the most of what has turned out to be a truly stunning comet!

At the beggining of this Image of the Week we promised to spoil you, and spoil you we will, with this breath-taking image of comet ISON recorded on November 16, 2013, by Waldemar Skorupa (Kahler Asten, Germany)!

In just four days, comet ISON went from being "pretty" to being "pretty spectacular"! German amateur astronomer Waldemar Skorupa recorded this image from Kahler Asten, in Germany, on November 16, 2013. If, like us, you want this as your new desktop wallpaper, you'll want the full-size file. [Image credit: Waldemar Skorupa (Kahler Asten, Germany), via]

It should be noted that while comet ISON is now being reported as a naked eye object in some locations, you should not expect it to look like this in the night sky! Images like the one above, and similar gorgeous shots by Damian Peach, for example, are taken with specialized equipment, powerful telescopes and years of experience in processing astronomical images. Most visual (including binocular) observers are reporting comet ISON is mainly a "green fuzzball", with maybe a very faint tail visible.

With only 10 days until perihelion, comet ISON will soon disappear into the Sun's glare. During this time, we will monitor it with an armada of solar satellites including NASA's SDO and STEREO satellites, and the ESA/NASA SOHO satellite. These images will be posted directly online as soon as the data is retrieved from the spacecraft, mostly in real-time, and we will let you know those links nearer the time.

So stay tuned to this website in the coming days as we guide you through the most perilous part of comet ISON's journey through the solar system. Will it be fried by intense solar radiation? Will it be ripped apart by the Sun's extraordinary gravitational pull? Or will it survive in one piece and become a spectacular night sky object? We have no idea, but we can't wait to find out!

Every week this year we will put up a new image related to Comet C/2012 S1 (ISON). If you have a cool image you'd like us to consider, please send it to, along with a description and any credits you would want applied. We'll contact you if we choose to use your image on the CIOC Website.

See our ISON Image of the Week Archives for earlier picks!