I’m takin’ it easy for Lincoln’s Birthday (he was a distant relation, actually, so I deserve it). Look! A Spitzer image! And no, I’m not just logrolling for my friend Robert. I took a look at today’s press release, and I couldn’t find anything else to blog about, then…
I take a closer look. I thought I’d link to the Hubble Space Telescope picture of the Helix and make some kind of comparison. But when I skipped between the two images, I noticed that the two seemed to be rotated 90° with respect to one another. Odd. For a quick double-check, I took a look at Rob Gendler’s (as always gorgeous) picture of the Helix, and it seems to match Hubble’s.
Here, I’ll save you the trouble and link to an essentially equivalent picture (with the Hubble color scheme) from Travis Rector:
Yep, it’s rotated. Bizarre!
I mean, honestly, it’s not a big deal. But it might be considered a little confusing not to have imagery from the NASA Great Observatories lining up properly.
Otherwise, I was just going to note that it’s interesting how the exterior of the nebula shifts from red-yellow in the Hubble image to blue-green in the Spitzer view: purely a matter of convention, of course, since images are typically mapped by wavelength, with shorter-wavelength light being mapped to (ironically) cool colors and longer-wavelength light to (equally ironically) warm colors. The red haze at the center of the Helix in the Spitzer image indicates a source of small, warmed particles—interpreted to be colliding comets in the aforementioned press release.
The Hubble site offers a “tour” of the Helix, which is quite nice. Perhaps we&rsquo’ll be treated to a different tour in a future interactive—one which shows the nebula not just in optical light, but in its intriguing infrared emission as well.