Thursday, September 10, 2009

In love with Hubble all over again

NGC 630 caught on Hubble's new camera

It may have a boring name, the nebula known as NGC 630 is a minor celebrity these days. This butterfly-shaped cloud of gas, pluming spectacularly from a distant dying star, is all over the Web right now. It's one of the first images snapped by the Hubble Space Telescope since STS-125 astronauts replaced its camera and upgraded its instruments in May.

The Wide Field Camera 3
At 19 years old, Hubble may have seemed a bit young for a facelift. But, as any PC or camera owner knows, a lot has happened in the world of electronic and optics in the last 19 years. Judging from these first images, the Wide Field Camera Three is doing a fantastic job. Although it shares the same ultraviolet through infrared range as the Wide Field and Planetary Camera 2, its field of view and resolution outshine that of the retired Whiff Pick Two.

As the Christian Science Monitor points out, there's a marked difference in the new photos, which boast a crisper image and exquisite detail. And there should be: the makeover cost NASA nearly a billion dollars. But it's giving the aging telescope a new lease on life; NASA estimates that Hubble's instruments, assuming no major disasters, will funnel in rich data from the great beyond for another four to five years. When its instruments fail, the scope will be de-orbited, which is a euphemism for burning up in the atmosphere, and replaced by the next generation James Webb Space Telescope.

Before and after image of the Omega Centauri star cluster, 16,000 light-years away.


These photos are gorgeous, but that's not only thanks to Hubble. The WFC3 sees electromagnetic radiation in ultraviolet through infrared, which is wider than thethe narrow slice of the spectrum human eyes perceive. So data that falls outside the visible is assigned a representative color so humans can see the details. That's the case in the photo below of Saturn, shot in infrared (before the revamp).

An infrared shot of Saturn.


Another technique is to assign colors to the very specific wavelengths emitted by different chemical elements. For the famous photo of the Eagle Nebula below, image processors assigned the red, green, and blue to emissions of ionized sulfur, doubly-ionized oxygen, and hydrogen atoms.

The Eagle Nebula painted in chemical elements.


I remember feeling cheated when I first learned that Hubble's colors weren't "real," but now that seems like a closed-minded reaction. Human perception is extremely limited, and placing this data within grasp of our limited eyesight is simply the best way to convey the complexity and structure of these objects. For an in-depth explanation of how Hubble images are processed, check out this article from Slate.

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