Posted on by Nancy Atkinson

Astronauts Open New Window on the Universe

"Let there be light! Cupola windows open toward Sahara desert. Priceless!\" Tweeted ISS astronaut Soichi Noguchi.

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“Let there be light! Cupola windows open toward Sahara desert. Priceless!” Tweeted ISS astronaut Soichi Noguchi from the ISS.

It’s the moment we’ve all been waiting for: the opening on the windows of the new Cupola on the International Space Station. And it was incredible.

“As expected, the view through window seven is absolutely spectacular,” ISS commander Jeff Williams said. “When we have the others around it open, it will give us a view of the entire globe. Absolutely incredible.”

Shutters are opened on the new Cupola on the ISS. Credit: NASA TV

The new $27 million bay window was uncovered during the third EVA of the STS-130 mission by spacewalkers Nick Patrick and Bob Behnken, who removed the protective launch covers and bolts. Then, from the inside, each of the seven shutters was cranked opened and closed one at a time, to test the view — and the shutters. In case there were any problems, the astronauts out on EVA could help close the shutters.

Later, all the shutters were opened at once for the full view. “I don’t think space station’s ever going to be the same after this,” Mission Control radioed to the ISS.

The new observation deck will allow astronauts unprecedented 360-degree views of Earth and space, while providing a new location for robotic operations where astronauts inside the ISS can actually watch directly what they doing with the CanadArm2 on the ISS, instead of completely relying on computer inputs and camera views. The Cupola is attached to the nadir, or Earth–facing port of the new Tranquility node, a $380 million addition to the station that was delivered to the ISS on the current space shuttle mission.

Built by the Italian space agency, the Cupola is 1.5 meters (5 feet) tall and about 3 meters (10 feet) in diameter. Six rectangular windows encircle the dome, with a large circular window in the middle.

Mission managers said at a press conference last week that the windows will remain shuttered most of the time to protect the 4-pane fused silica glass from micrometeroid strikes. The large central window shutter may be allowed to opened more frequently since it is facing towards Earth and away from potential incoming space debris.

Nancy peeks through a model of the Cupola that was at Kennedy Space Center. Image by Robin Hobson.

A model of the Cupola was set up at the press room at Kennedy Space Center. I asked about the windows and the potential of problems if they are hit by micrometeroids, and was told that if the windows are dinged or significantly damaged, they can be repaired or replaced on orbit. There are spare window assemblies built, but they aren’t currently on the ISS nor are there plans to bring them up, for now. For minor damage, the shutters would be closed until the repairs could be done. For major damage, the Cupola has a hatch, so there is the potential to close off Cupola, but mission managers said that option has a very low likelihood of occurring.

Posted on by Nancy Atkinson

Asteroid Might be Visible to Naked Eye on Feb. 17

Asteroid Vesta as seen by NASA's Hubble Space Telescope. Image credit: NASA/ESA/U of Md./STSci/Cornell/SWRI/UCLA

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An asteroid could be visible with binoculars, or even the naked eye on Wednesday, February 17, 2010. No, it’s not coming close to Earth, although this second most massive object in the asteroid belt will be at its closest point to Earth in its orbit, about 211,980,000 kilometers (131,700,000 miles) away. Asteroid Vesta – one of the asteroids that the Dawn spacecraft will visit – will be at opposition on Wednesday, meaning it is opposite the sun as seen from Earth, and is closest to us. Vesta is expected to shine at magnitude 6.1, and that brightness should make it visible for those with clear skies and a telescope, but perhaps even those blessed with excellent vision and little or no light pollution. Vesta will be visible in the eastern sky in the constellation Leo, and will continue to be visible — although less so — in the coming months.

What makes this space rock so prominent these days? Along with its relative proximity at this point, a full half of the asteroid is being bathed by sunlight when seen from Earth, making it appear brighter. Another attribute working in the observer’s favor is that Vesta has a unique surface material that is not as dark as most main belt asteroids – allowing more of the sun’s rays to reflect off its surface.

For more info about observing Vesta, check out this article from Sky & Telescope.

If you get lucky enough to see Vesta, and want to learn more about it, check out this info on the Dawn mission website. Dawn is currently motoring its way through the asteroid belt, will begin its exploration of Vesta in the summer of 2011.

Source: JPL

Posted on by Nancy Atkinson

Big Full Moon and Mars Put on a Show Friday Night

An almost full Moon on Jan. 27, 2010. Credit and copyright: Alan Walters

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If your skies are clear on Friday night, January 29, 2010, take advantage of one of the skywatching highlights of the year. A full Moon and Mars will be putting on a show, and the pair will be prominently close to each other in the sky. Plus, this Friday night’s full Moon is the biggest and brightest full Moon of the year. It’s a “perigee Moon,” as much as 14% wider and 30% brighter than other full Moons you’ll see later in 2010, according to Spaceweather.com. And, even though you’ve likely not gotten an email from an excited acquaintance relaying that Mars is really close to the Earth now — that is the case. Mars is at opposition on the 29th, which means it lines up opposite the Sun and is now the closest to Earth their orbits, and so will shine brighter.

The image above of the not-quite-full Moon from January 27, 2010 is shared by Universe Today reader Alan Walters, from Florida. You can see more of his wonderful photography of the night sky, launches and shuttle landings, Florida wildlife and more at Alan Walters Photography.

Positions of the Moon and Mars. Credit: McDonald Observatory

This image, courtesy of Stardate Online and the McDonald Observatory, shows the positions of the Moon and Mars in the night sky the next few evenings.

This is not a great opposition for Mars because it occurs around the time that Earth is closest to the Sun and Mars is farthest. The gap between the two planets will be a hefty 62 million miles (99 million km). The smallest possible distance at opposition is about 35 million miles (56 million km), which happened a back in August of 2003, and prompted the infamous emails that now surface every August, that Mars would be as big the full Moon, which of course, is not — and was not — true. Mars appeared more than twice as bright then as it will this year, but was still a star-like dot in the sky.

JPL is sponsoring a Facebook Event, Friday Night With the Moon and Mars, to heighten awareness of what a great sight it will be; plus its a great way to share in the experience with others online.

And for more information, see this Science@NASA article about the close encounter.

Sources: Stardate, Spaceweather.com

Posted on by Nicholos Wethington

Epsilon Aurigae Eclipse Mystery Solved with Your Help

If you’ve been helping out with the Citizen Sky project to monitor Epsilon Aurigae, then congratulations – the first of the results are in! Donald W. Hoard, a research scientist at Caltech announced the findings at the American Astronomical Society meeting in Washington, D.C. this morning. We invited our readers to participate in monitoring the star in August of 2009, and combined with observations from Spitzer, a 200-year old mystery has potentially been solved.

Epsilon Aurigae is a bright star in the constellation Auriga. It began to dim in brightness last August, which it does every 27 years. The star dims for over 2 years, with a slight brightening in the middle of the eclipse, making it the longest known orbital period for a stellar eclipse. The Citizen Sky project invited professional and amateur astronomers alike to aid in the observation of the star during this eclipse.

What exactly passes in front of the star was a mystery, though it was thought that a large disk of material with two stars orbiting tightly in the center is the cause of the eclipse. The disk itself is pretty huge – on the order of 8 astronomical units. There is a slight brightening during the middle of the eclipse that led astronomers to believe there is a hole created by the two stars in the center.

“If [Epsilon Aurigae] were an F star, with about 20 times the mass of the Sun…a single B star at the center of the disk doesn’t have enough mass to explain the orbital dynamics,” Hoard said. Other possibilities proposed were the presence of a black hole at the center of the disk, but there were no telltale X-rays coming from the system that would show a black hole was heating up matter in the disk.

Through observations by astronomers that participated in the project, as well as observations made by the Spitzer space telescope, a major revision of the properties of Epsilon Aurigae itself were in order.

“What we were most pleased to find an answer to… was that the results strongly tip towards a 2 solar-mass dying star. Sometime in the next few thousand years it will emerge as a planetary nebula,” Hoard said.

This means that instead of being a 20 solar-mass F-star supergiant, Epsilon Aurigae is in fact a 2 solar-mass F-star which is in the last stages of its life, and thus giant in size – about 300 Suns across. This, combined with a single B-star of about 5.9 solar masses at the center of the disk that orbits Epsilon Aurigae fit the observations very well, Hoard said.

Arne Henden of the American Association of Variable Star Observers (AAVSO), commenting on Hoard’s presentation at the press conference, said “Don says that we solved it, and I disagree. We need to determine the nature of the dusty disk that is involved – these are things that you see around young stellar objects, not older stellar objects.”

Hoard said that there was a curious property of the disk in that it was composed of larger grains of dust – more like grains of sand than microscopic dust motes.

“The observations that are being made by Citizen Sky project…will hopefully help answer this by providing answers about the composition of the disk and the temperature zones as the eclipse continues. We have these results in large part due to the effort of this huge group of citizen astronomers that are observing Epsilon Aurigae,” he said.

Epsilon Aurigae is still undergoing its eclipse, though the first phase ended right around the New Years Eve 2009. It will continue to be dim until early 2011, when it will begin to brighten again. There is still a lot to be answered about this system, and your help is needed, so keep (or start) observing and reporting! For more information on how to do so, visit Citizen Sky.

Source: AAS press conference on USTREAM, Citizen Sky press release

Posted on by Jean Tate

Altazimuth

Radio Telescopes. Credit: University of Washington

Altazimuth is a contraction of altitude-azimuth; in astronomy it most often refers to a type of telescope mount (and is sometimes called alt-az), but it can also mean a coordinate system.

Altitude means the angular distance above the horizon; straight up (overhead) is 90o (and is called the zenith). Azimuth is also an angular distance, measured clockwise from north (so east is 90o). Any point, or direction, in the sky has one – and only one – altitude and azimuth; in other words, the altitude and azimuth are the coordinates of the point (on the celestial sphere).

An altazimuth telescope mount is one that can move separately in altitude (up and down, vertically) and azimuth (side to side, horizontally). Small telescopes used by amateur astronomers tend to have altazimuth mounts; larger ones tend to have equatorial mounts … unless they are Dobsonian. Why? Because while alt-az mounts are generally cheaper, tracking astronomical objects (like stars) is much easier with equatorial mounts.

Historically, the telescopes used by professional astronomers did not have alt-az mounts, because automatic tracking was impossible. As computers became powerful and cheap enough, they could be used to control the motors on each axis of an altazimuth mount; today, almost all ground-based astronomical telescopes have altazimuth mounts, whether optical, radio, or even high energy gamma ray! The first really large optical telescope to use an altazimuth mount is the 6-meter Bol’shoi Teleskop Azimultal’nyi, in Russia.

Universe Today’s Telescope Mount, Telescope Parts, Telescope Tripod, and How To Use a Telescope are great resources for learning more.

The Astronomy Cast episode Choosing and Using a Telescope covers the benefits of alt-az mounts (vs equatorial), and Telescopes, the Next Level gives insight into tomorrow’s professional ones.