Photograph by Terry Renna, AP
Published July 7, 2011
But for those who can't make the trip to Florida, the upcoming STS-135 mission marks the last time sky-watchers around the world will have the chance to see a shuttle passing above their backyards.
Depending on where you are on Earth, both Atlantis and the International Space Station (ISS) should be visible to the naked eye during the mission, which is scheduled to last for 12 days.
When skies are clear, Earthbound viewers generally see both the shuttle and the ISS as fast-moving "stars." The spacecraft are easy to spot, because they're among the brightest objects in the night sky.
Even while Earth is cast in shadow, the orbiting objects are being hit by direct sunlight, which reflects off their shiny, metallic surfaces.
Still, knowing exactly when and where to look is crucial: The spacecraft are moving at about five miles (eight kilometers) a second, and they'll cross the sky in just a few minutes.
"They move very fast, so a telescope would not be the recommended way to observe for novice sky-gazers," said Raminder Singh Samra, an astronomer at the H.R. MacMillan Space Centre in Vancouver, Canada.
"Binoculars will allow you to scan the sky fairly quickly and at low enough magnification to provide a steady image."
Shuttle Launch Time Will Affect Views
Anyone wanting to catch the shuttle in flight will need up-to-the-minute viewing timetables, said Anthony Cook, an astronomical observer for Griffith Observatory in Los Angeles, California.
"Because the shuttle and ISS orbits are sometimes changed"—to move them out of the path of orbiting space junk, for example—"the timing and visibility become a little uncertain when projected more than a week into the future," Cook said.
"So anyone hoping to see or photograph the shuttle, the ISS, or a particular event happening with them will need to pay attention to several sources of information."
Current predictions based on a July 8 shuttle launch indicate that observers in the Southern Hemisphere will have the best viewing opportunities. But if there are launch delays, the ideal viewing locations will change.
Spy a Cosmic Chase
Time your shuttle viewing just right and it's even possible to observe special in-flight events.
One of the most exciting sights for sky-watchers is to catch a double flyby of the shuttle and the ISS, H.R. MacMillan's Samra said.
In the hours before docking and after undocking, Atlantis and the space station will have the same flight paths, so they'll appear to be chasing each other.
"On the third day of STS-135, the shuttle will dock with the ISS. If the ISS is visible in an observer's location, it will be possible to catch the shuttle as a moderately bright satellite getting closer to the ISS after each subsequent orbit," Samra said.
Another viewing spectacle is when the shuttle dumps its wastewater after undocking from the station.
When the water hits the low-pressure and low-temperature environment of space, it freezes, but sunlight quickly turns the ice into vapor, Samra said. (See a picture of the shuttle Discovery dumping wastewater during its final flight.)
"This mist has been observed from the ground ... and I would advise the use of a pair of binoculars to enhance the view of the shuttle and any potential wastewater."
The Right Stuff for Shuttle Shots
Any shutterbug wanting to capture a keepsake of the last shuttle flybys will need a digital camera with manual settings and a tripod, said the Griffith Observatory's Cook.
"To photograph the path of the space station and shuttle as a streak, you will need to expose for anywhere from a few seconds to as much as six minutes, depending on how wide your field of view is or how much of the trail you want to get," he said.
(Related: "Best Night-Sky Pictures of 2011 Named.")
More experienced stargazers with telescopes or binoculars may also want to try and take a detailed look at Atlantis and the ISS as they zoom across the sky.
"The ISS can look several times larger than Jupiter and shows an incredible amount of detail," Cook said.
"It even looks square through [ten-times zoom] binoculars, and seeing it streak against the stars drives home just what 'five miles per second' means!"
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