First photos of Comet ISON from Mars

Two of four images released today of Comet ISON photographed by the orbiting MRO from Mars on Sept. 29. Click to enlarge. Credit: NASA/JPL/University of Arizona

The first pictures of Comet ISON taken by the Mars Reconnaissance Orbiter (MRO) are finally here. That’s it? OK, they’re probably not what we were expecting, but they do give astronomers information about the comet’s size from a different perspective than Earth. Keep in mind that the spacecraft’s cameras were optimized to stare down at the sunlit surface of Mars, not poke around the sky looking for comets.

Two more images of the comet taken by MRO. Credit: NASA/JPL/University of Arizona

Even though ISON was only 8 million miles (12.9 million km) when the pix were shot on Sept. 29, the comet is very faint. According to predictions this puts ISON at the low end of brightness expectations. It also constrains the size of the comet’s nucleus, a key indicator of whether it will survive it fiery brush with the sun late next month. Bigger is better of course!

“The image has a scale of approximately 8 miles (13.3 km) per pixel, larger than the comet, but the size of the nucleus can be estimated based on the typical brightness
of other comet nuclei,” according to today’s press release.

Three more observations of Comet ISON are planned for today and tomorrow.

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About astrobob

My name is Bob King and I work at the Duluth News Tribune in Duluth, Minn. as a photographer and photo editor. I'm also an amateur astronomer and have been keen on the sky since age 11. My modest credentials include membership in the American Association of Variable Star Observers (AAVSO) where I'm a regular contributor, International Meteorite Collectors Assn. and Arrowhead Astronomical Society. I also teach community education astronomy classes at our local planetarium.

13 thoughts on “First photos of Comet ISON from Mars

  1. I was being optimistic that at perihelion, ISON could just edge the daylight comet of 1882, but this is beginning to look a little more doubtful.

  2. I have not seen Saturn in week or so. It must still be visible to the naked eye now setting 81 minutes after the Sun, and 17 minutes before Venus. In less than 8 weeks, it will be close to Comet ISON. I am still optimistic that at that time ISON will be the brighter of the 2.

  3. These pics consolate myself, as my first pic of Ison (from city with Moon, clouds and alt-az mount) aren’t much better :) And it’s good news that the orbiter is not furloughed by the US gov shutdown.

    PS I just checked Nova Del in the C8: respect last week, even more fainter and redder (in agreement with the AAVSO curve). In visual the change is very sensible, both in brightness and color, where the star now appears almost red. The camera (not modified) shows it still purple/magenta, even at low exposition, but more saturated than last week.

  4. We’re certainly getting some conflicting reports of Ison.Some are pessimistic(although the MRO pics are so grainy that would take them with a proverbial grain of salt,lol) while some reports(from BAA,spaceweather) have Ison brighter than Lovejoy 2011 was at same distance from sun.Also,Yoshida’s latest brightness curve was very optimistic.So,mixed signals.Am not TOO worried yet but hope this doesn’t pull another Kohoutek….

    • Edward,
      Even if it appears to be only slowly brightening this fall, I’m not too worried. As long as it survives perihelion, we’ll have a very nice comet to view.

  5. Hey Astrobob.. Do we have any images of Mars after ison has passed by?
    I think that would be a preview for earth.. This would show if there are comets coming along it.
    Thank you!

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