Emily LakdawallaMay 03, 2013

New Deep Impact Hartley 2 data set

I've spent a pleasant couple of hours playing with a new data set. This new data set contains images we've all seen before, taken by Deep Impact during its flyby of comet Hartley 2 in November of 2011. One of Deep Impact's cameras, the High Resolution Imager, had a defect that made its images blurry. The newly released data set is a "deconvolved" one, where they have attempted to correct for this blur. The deconvolution introduced some other artifacts -- there's no way to make these photos perfect -- but they are fun to play with nonetheless.

Here's the result of some late-night play with the image data. The original data was taken near closest approach.

Comet Hartley 2
Comet Hartley 2 The Deep Impact flyby spacecraft performed several extended missions after observing the Deep Impact impactor hitting comet Tempel 1 in 2005. In November 2011, it encountered comet 103P/Hartley 2. Hartley 2 was unusually active for a comet, its jets easily visible to Deep Impact's cameras without substantial processing.Image: NASA / JPL / UMD / processed by Emily Lakdawalla

Comet images are tough to process because you want to see the jets (they are comets, after all) but the jets are inherently fainter than the rest of the nucleus. If you stretch the contrast to reveal the jets, you often wash out detail on the nucleus. It's even more of a problem with these Hartley 2 photos because of all the artifacts. I can't say there was much science to my image processing method here -- it was just futzing around in Photoshop until something happened that I was pleased with. But maybe it's reproducible.

I left the original photo more or less in its original form, and created a copy on a second layer. I stretched the contrast in that copy, which brought out the jets but also brought out all the ringing artifacts from the image deconvolution. Then I applied a Gaussian blur to the copy, which removed the rings but also fuzzed the image considerably. Then I reduced its opacity, overlaying fuzzy jets onto the sharper image of the nucleus. This is definitely more art than science, but I'm happy with how it looks.

The Planetary Fund

Your support powers our mission to explore worlds, find life, and defend Earth. Give today!