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Emily LakdawallaNovember 5, 2010

Hartley 2 compared to other comets, and in motion 3D

I had to catch up with tasks left undone at home today and didn't have time to write up my notes from the Hartley 2 press briefing, for which I apologize. I'll leave you for the weekend with three cool Hartley 2 pictures.

First, I've composed a montage of all five comets whose nuclei have been imaged directly by spacecraft, to scale with each other, sized for inclusion in your favorite digital presentation software. Hartley 2 is the smallest comet ever visited by a spacecraft!

Comets visited by spacecraft

Halley: Russian Academy of Sciences / Ted Stryk. Tempel 1 and Hartley 2: NASA / JPL / UMD. Borrelly: NASA / JPL / Ted Stryk. Wild 2: NASA / JPL. Montage by Emily Lakdawalla.

Comets visited by spacecraft
As of November 5, 2010, five comet nuclei had been directly imaged by flyby spacecraft. They are shown here to scale with each other, at 20 meters per pixel (in the click to enlarge version).

I get a lot of requests for reuse of these kinds of images. People may absolutely use these in their presentations. I'd love to get an email if you're planning on using it! Please keep the credit line intact -- each image is from a different mission, who should get credit for the data, and Ted Stryk put in a lot of work processing those Halley and Borrelly images. Please contact me first before using it in a publication.

Here's another size comparison, just for fun: Hartley 2 and the International Space Station (upper left corner). Hartley 2 is very small as space objects go, and the Space Station is enormous as human-built spacecraft go; it's pretty remarkable that one can see both things at the same scale within a Web browser! (However, I wouldn't recommend that the Station actually approach a comet this closely -- I don't think it's shielded properly for that environment!)

Hartley 2 compared to the International Space Station

NASA / JPL-Caltech / UMD / comparison by Emily Lakdawalla

Hartley 2 compared to the International Space Station
Just for fun, a size comparison of the International Space Station (upper left corner) and Hartley 2's nucleus.

Finally, get out your 3D glasses. This cool animation is the result of a group effort among the space enthusiasts at, which is now part of the Planetary Society! There's no new Hartley 2 data in here; it was just made, by Daniel Macháček and Luca Cassioli, by morphing among the five images that were released yesterday and then using sequential images from the morph animation to make the anaglyphs.

3D animation of comet Hartley 2's nucleus

NASA / JPL-Caltech / UMD / Daniel Macháček / Luca Cassioli

3D animation of comet Hartley 2's nucleus
Use red-blue glasses to see the 3D effect. To compose this animation of the nucleus of comet Hartley 2, Daniel Macháček used Sqirlz Morph to morph among the five images of the nucleus that were released by the Deep Impact team on the day of the flyby, November 4, 2010, in a process explained here. Then Luca Cassioli took sequential frames from the morphed animation and used them as left and right images in this animated GIF.

Not ten minutes after I posted the above and went to pick up my kids, the Deep Impact team posted a video of the flyby, which contains more images from closest approach than have been released before. I'm posting it late Friday evening so don't have time to take it apart myself; but I'm sure some of you readers will have fun deconstructing it and finding higher-resolution shots of the comet! Here it is on Youtube, but if you follow this link you'll get to a version in Quicktime format.

Please accept marketing-cookies to watch this video.

NASA / JPL-Caltech / UMD

Deep Impact's flyby of Hartley 2

Have a great weekend!

Read more: pretty pictures, comets, Deep Impact, amateur image processing, comet Hartley 2, global views, 3D, animation

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Emily Lakdawalla

Senior Editor and Planetary Evangelist for The Planetary Society
Read more articles by Emily Lakdawalla

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