ISON Image of the Week

Eight Spacecraft and Counting  (Nov 04, 2013)

The Comet ISON Observing Campaign is both terrestrial and celestial! Here we show observations from the eight different NASA and ESA spacecraft that have observed comet ISON so far. There are still more to come! [Image credits can be found in the appropriate links at the bottom of this page.]
From the beginning, the Comet ISON Observing Campaign (CIOC) set the goal of making this observing campaign both terrestrial and celestial, meaning we wanted to encourage and facilitate observations of the comet from every major observatory that could conceivably make them, regardless of whether they were on Earth or in space. A quick glance at our Observing Plans Calendar should convince you that this is going rather well so far, with numerous large facilities and observatories dedicating significant telescope time to observing comet ISON.

Ground-based observatories and telescope have it lucky, however, as they are primarily designed to look at objects like comets. Space-based observatories are not necessarily in the same situation. The ESA/NASA Solar and Heliospheric Observatory (SOHO), for example, is designed to look at the vast ball of burning gas at the center of our solar system that we call our Sun. The NASA Mars Reconnaissance Orbiter (MRO) is designed to look at the surface and atmosphere of a planet that's only a few hundred miles away. Yet both of these mission plus six others - only one of which was actually designed to study comets - have contributed valuable observations to the CIOC!

Opposite, we have collected observations from each of these space-based observatories and placed them into a single image. These were all taken at different times throughout 2013, and from very different locations in space. At the bottom of this page we give links to information about each one of these observations, but what we want to emphasize here is the diversity of observations and the spacecraft that have recorded them. We have missions from the planetary, astrophysics, and heliophysics communities contributing science to a campaign that is backed up by an army of professional and amateur astronomers on Earth. Together, these are part of the most technologically advanced fleet of astronomical instrumentation in history, coming together to study ISON in the hopes of learning about its origins, structure and composition, and in turn maybe shed light of how our solar system was formed, and how we came to be.

It's important to note that the spacecraft observations we highlight here are certainly not the end of the story. At time of writing, the MESSENGER mission at Mercury has started daily observations of comet ISON, and the Chandra X-Ray telescope has set its sights on the comet. More observation attempts are expected from the ESA Venus Express and Proba-2 satellites, and the NASA Solar Dynamics Observatory, to name but a few.

Unfortunately, none of these missions can guarantee a successful detection of the comet, and we can't even guarantee that the comet will survive long enough for them to get their chance at it. ISON is not a big comet, and as it's the first time we've ever seen it, we have no idea if it can withstand the increasingly hostile inner solar system. We would love to be able to promise that just over one month from now, the night skies will be illuminated by a visually stunning comet. However, we can offer no such promise. But at this stage, with it inside the orbit of Earth and closing in fast on the Sun, even if it does fragment or vaporize we have enough observatories and instrumentation pointed at it that we will gain a truly enormous wealth of scientific data about the comet. The CIOC was formulated in order to generate new scientific results and understanding, and that we can promise!

The observations in the above image came from the following missions [clockwise from top-center]: NASA Spitzer, NASA Deep Impact/EPOXI, NASA Hubble, NASA STEREO-B, NASA Mars Reconnaisance Orbiter, ESA/NASA Solar and Helisopheric Observatory, NASA SWIFT, NASA STEREO-A

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!