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In one-of-a-kind photo, Hubble and Venus cross sun

Thierry Legault / Astrophoto.fr

French astrophotographer Thierry Legault captured this view of the Hubble Space Telescope passing over the sun's disk during this week's transit of Venus. The circles highlight the Hubble on multiple exposures taken every tenth of a second during the telescope's 0.9-second transit.


Over the past few days, we've seen lots of amazing photos showing Venus' last-in-a-lifetime crossing of the sun, but this shot of the Hubble Space Telescope zooming past Venus may be the only picture of its kind.

It's actually a combination of photographs, snapped every tenth of a second by master astrophotographer Thierry Legault. Nine speck-sized images of Hubble are highlighted with circles in the image. Legault, who is famed for his pictures of spacecraft transits across the sun, traveled from his home base in France to northern Australia for the shot.


After conducting the calculations with CalSky software, Legault made sure he was in Queensland at 01:42:25 UTC June 6, pointing his Takahashi FSQ-106ED telescope at the sun with the proper filters attached. "Thanks to the continuous shooting mode of the Nikon D4 DSLR running at 10 fps [frames per second], nine images of the HST were recorded during its 0.9s transit (1/8000s, 100 iso, raw mode). Turbulence was moderate to high," Legault reported on his website.

You read that right: While it took Venus more than six hours to inch its way in front of the solar disk, the Hubble Space Telescope zipped across in just nine-tenths of a second. Imagine how disappointing it would have been to have a cloud in the way at that moment!

Legault is promising more pictures of Venus, taken during the transit and afterward. But it'll be hard to match this one. The next transit of Venus won't occur until the year 2117, and even though Hubble has long outlasted its projected lifetime, the space telescope will surely be sent down to its fiery doom by then. So chances are this is the only picture that will ever be taken of Hubble and Venus simultaneously silhouetted by the sun.

By the way, Hubble was conducting its own transit tasks during Venus' crossing. Hubble focused on the moon and analyzed  the reflected sunlight to find out how easy it will be for future telescopes to pick out the spectral signature of Earthlike planets passing over alien suns. Stay tuned for more about the results of that experiment.

Where in the Cosmos
This picture served as today's photo puzzle for our "Where in the Cosmos" contest, open to Cosmic Log Facebook followers. It took just a couple of minutes for Ollie Nanyes to tell me what those little specks represented. For being so quick on the draw, I'm sending Nanyes a pair of 3-D glasses donated by Microsoft Research's WorldWide Telescope project. Kent Avery, the runner-up in the guessing game, is getting 3-D specs as well. (Microsoft is a partner along with NBC Universal in the msnbc.com joint venture.)

The cardboard-and-cellophane glasses I'm sending Nanyes and Avery will be wrapped up in a 3-D picture of yours truly, but there are other, more interesting 3-D space pictures online. This Cosmic Log 3-D archive points you to some stunners. Click the "like" button on the Cosmic Log Facebook page, and you too may be eligible for some 3-D glasses goodness in the weeks to come. Just for fun, go full-screen on this simulated 3-D view of the transit from the National Solar Observatory Integrated Synoptic Program:

This is a simulated 3-D view of the Venus transit, prepared in advance of the event by the National Solar Observatory Integrated Synoptic Program, or NISP.

More wonders from Thierry Legault:


Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.