Snapshot: Shimmering Nebula Caught in Scorpion's Claw

Gripped in the claw of the constellation Scorpius (the Scorpion), the reflective nebula DG 129 twinkles in a new image taken by NASA's Wide-field Infrared Survey Explorer.

The WISE space telescope provides an infrared view of the reflection nebula ? so-called because the cloud of gas and dust reflects light from nearby bright stars.

Also visible in the image is a luminous star on the right, shrouded in a greenish fog. This star, called Pi Scorpii, marks one of the claws in the Scorpius constellation. The star is actually a triple-star system that is located approximately 500 light-years away from Earth.

In visible light, this portion of the sky would appear somewhat unremarkable. But in infrared light, the shimmering nebula is revealed. DG 129 was first catalogued in 1963 by a pair of German astronomers named Johann Dorschner and Josef G?rtler.

This image is just one piece of a massive sky atlas that the WISE space telescope is assembling. The spacecraft, which launched in December 2009, completed its main mission of scanning the entire sky in infrared light earlier in July.

In that time, the telescope captured more than 1.5 million images, uncovering hundreds of objects, including asteroids, stars and galaxies.

WISE relies on super-cold liquid hydrogen coolant to chill its infrared detectors, but in August, NASA reported that the telescope's secondary coolant tank is depleted, causing it to heat up slightly.

The colors used in the DG 129 image represent different wavelengths of infrared light. The photo was constructed from frames that were taken after WISE depleted its supply of coolant.

After the telescope warmed from minus 438 degrees Fahrenheit (minus 261 degrees Celsius) to minus 404 degrees F (minus 242 degrees C), its detector that is sensitive to 22-micron light became too warm to produce good images. The three shorter wavelength detectors, however, continue to beam back over 7,000 pictures of the sky per day.

In this image, blue represents infrared radiation at 3.4 microns, green represents light with a wavelength of 4.6 microns, and red represents 12-micron infrared light.

In May, a NASA panel rejected a proposal to extend WISE's mission for an additional three months.

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