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Headshot of Emily Lakdawalla

Venerable Deep Impact spacecraft has photographed comet ISON

Posted by Emily Lakdawalla

05-02-2013 17:24 CST

Topics: pretty pictures, animation, astronomy by planetary missions, comets, Deep Impact

Here is a neat animated GIF of observations of comet ISON made by the Deep Impact spacecraft. I'm told that these are the first space-based observations of this comet, which is expected to put on a major show late this year. Deep Impact was more than 5 AU away from the comet at the time, so it's just a distant fuzzball -- but you can clearly make out the cometary activity, which is pretty awesome.

Comet ISON from Deep Impact


Comet ISON from Deep Impact
Deep Impact observed comet ISON on January 17 and 18, 2013, taking more than 150 photos. The comet was more than 5 AU away from Deep Impact at the time. These were the first space-based observations of comet ISON.

This isn't the first time that Deep Impact has performed astronomical observations! This little spacecraft has performed followup observations on exoplanets and done deep-sky imaging. Of course Deep Impact was originally a comet mission, so its instruments were designed for looking at things like ISON -- though from a closer perspective.

Here's a little more information on plans for Deep Impact's comet ISON imaging campaign, from a press release:

The ISON imaging campaign is expected to yield infrared data, light curves (which are used in defining the comet's rotation rate) in addition to visible-light images. The current movie of comet ISON was generated from initial data acquired during this campaign. Preliminary results indicate that although the comet is still in the outer solar system, more than 474 million miles (763 million kilometers) from the sun, it is already active. As of Jan. 18, 2013, the tail extending from ISON's nucleus was already more than 40,000 miles (64,400 kilometers) long.

Deep Impact is one of several NASA missions that has been extended multiple times, and which periodically appears on the chopping block. This observation shows how Deep Impact is still capable of cool science, observing a comet from a perspective that you can't get from Earth.

See other posts from February 2013


Or read more blog entries about: pretty pictures, animation, astronomy by planetary missions, comets, Deep Impact


steve: 02/05/2013 07:27 CST

This is the comet that was discovered in the Bible Codes long ago. We've been talking about this event for over 5 years.

Dan Griscom: 02/06/2013 10:02 CST

Steve, I took a look at your page, and was intrigued your thesis that the Bible Codes state that a) this comet will annihilate the Earth, and b) "I" will destroy the comet. So, for your thesis to be validated, do both of these need to happen? Or, will you be able to point at any comet that meets its end during 2012 and claim validation? (BTW, SOHO detects many of these each year, just in case ISON ends up not meeting the needs of your particular model of reality.) I was especially intrigued by the list of "facts" supporting your thesis. Most interesting was #4: 'The path of a comet is difficult to predict because the tail acts as a “jet pack”'. ... really?

steve: 02/06/2013 02:39 CST

Dan, 1. Only one of the two Bible Codes predictions will come true. A. The sun will either destroy Comet Ison during it's approach. B. The comet will hit earth. If one of these two things do not occur then the Bible Codes can be considered incorrect or a hoax. 2. As a comet approaches the sun ice inside and outside of the comet will begin to melt. This will cause the release of pressure and debris from the comets nuclei. The force of the gases being released can change a comets course.

David Shortt: 02/07/2013 12:48 CST


Bob Ware: 02/08/2013 12:58 CST

What are the spec's on this comet? Regarding point 6; the size of the tail does not affect trajectory. The tail size is dependent on the solar wind strength. If by size you are meaning the ejecta velocity (AND its duration) that will be the effecting factor that pertains to the trajectory. 180 degrees after a burn, ejecta in this case, an orbital effect occurs. That is a change in flight path, comet orbital parameters in this case. Is the coma on this comet surface ablation or is it from deeper depths? These are trajectory factors also. Of course as it gets closer in more melting and ablation will occur. As this occurs if it heats enough material, deep enough, then some higher pressure ejecta is likely. That will have a noticeable effect on the trajectory.

Fall of a Thousand Suns: 04/16/2013 12:19 CDT

That distance puts it just beyond the orbit of Jupiter. Comet ISON will not hit Earth, or be even close as another user has commented. Its closest approach will be on December 26, 2013 when it will be 63,000,000 km (0.42 AU) from Earth. There are plenty of comets, which come much closer. For more information on Comet ISON, you should visit

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