June 10, 2011

Watch the ISS anytime you like….almost!

Near the northern summer solstice most, if not all night ISS passes are visible because of the high sun angle here in the northern hemisphere. Here are some of the best during the coming week.

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Louisville and southeastern USA

24 Jul 06:06:57  SW>NE

Chicago-Dallas midwest

24 Jul 05:07:36 SSW > ENE

26 Jul 04:48:00 SW > ENE

Dallas

24 Jul 05:06:30 30 S > ENE

26 Jul 04:48:00 72 NE > NE

Denver

27 Jul 04:24:47 SSW > 68 ENE

LAX

26 Jul 04:20:18 80 S > NE

Seattle/Pacific Northwest

31 Jul 04:19:00 WSW >> 87 ENE

Above sightings are for locales as noted and all times are local daylight time. For any other location click the Heavens-Above link at the right.

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June 9, 2011

Saturn “dances” with a Double Star

 

saturn-porrima-9-jun-11.gifThe ringed planet, Saturn, is spendidly placed near a double star as dusk falls this month. We were closest to it in April but this month’s show is interesting for a couple of reasons. Firstly, Saturn will be doing a “retrograde loop”. Until June 14th it will move “retrograde”, that is, westward relative to the stars. It will resume direct, eastward motion on the 14th. For the entire month of June Saturn will appear within less than a degree of the double star Gamma Virginis, also known as Porrima.

The chart above left shows the southwestern sky at 10 pm local time June 9th. Constellation Virgo “follows” Leo, the Lion just to the Lion’s east. Chart prepared using Your Sky

Although Earth is pulling away from Saturn this month’s celestial dance offers something for everyone. Naked eye observers can look for the planet and try to visually separate it from the Porrima double star. It’s also fun to watch from night to night and see if you can detect the planet’s motion against nearby stars. For binocular viewers watch the planet’s motion from night to night and it’s rings.

 saturn-porrima.jpg

Observing this apparition is even more interesting for those with telescopes. If you have a scope do all of the above and try to split the Porrima double. You’ll need a scope with aperature of at least 10 inches. Saturn and constellation Virgo are about halfway up in the sky to the south-southwest an hour after sunset.

Chart courtesy of Starry Night Education

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June 8, 2011

Having a “cool blast” on the Sun

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The Sun unleashed an M-2 (medium-sized) solar flare, an S1-class (minor) radiation storm and a spectacular coronal mass ejection (CME) on June 7, from sunspot complex 1226-1227. The large cloud of particles mushroomed up and fell back down looking as if it covered an area of almost half the solar surface. Image left: Courtesy NASA Solar Dynamics Observatory Click image for video

These solar flares and CMEs occur when magnetic loops collide above the cooler “sunspots”. The size of the eruption apparently has scientists puzzled and much of the relatively cooler, (around 80,000 K) ejected plasma fell back to the Sun causing sparkling mini flares as the plasma hit the much hotter photosphere..

“I’ve never seen material released like this before,” stated C. Alex Young, solar physicist of NASA’s Goddard Space Flight Center. “It looks like somebody just kicked a giant clod of dirt up into the air” Young added.

This not-squarely Earth-directed CME is moving at 1400 km/s according to NASA models. The CME should deliver a glancing blow to Earth’s magnetic field during the late hours of Wednesday, June 8th or early Thursday, June 9.  High-latitude sky watchers should be alert for auroras when the plasma arrives.

More related video from NASA Solar Heliographic Observatory and STEREO

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June 1, 2011

Endeavour and ISS, an amazing sight

Right on schedule at a few minutes before 5am Monday morning, 30 May Shuttle Endeavour and ISS rose above the western horizon at my place in southern Indiana. A bit blurry eyed from lack of sleep, I was at the ready. The digital camera was snug atop a tripod and aimed in approximately the right direction. I’d been watching NASA-TV. Endeavour had undocked some five hours earlier and had just completed the STORRM docking exercise. Ten minutes before the Station and Shuttle were to pass overhead I heard STS-134 Commander Mark Kelly call ISS and say “we’re at 950 feet, that’s as close as we’re going to get”. Eight minutes before the pair of space travellers were to appear to my west Endeavour fired a separation burn. I thought to myself “they’re going to be really close together” and wondered whether I’d be able to visually separate the two spacecraft.

endeavour-iss-font-31-may-11.JPG Image left: Shuttle Endeavour is the lower, dimmer streak in this 20 second exposure. The Shuttle was likely about 10,000 feet from Station when this image was taken. Click to enlarge image (c) 2011 Mark Steven Williams

Endeavour and the Station were due to appear at 0946 UT (4:46 am EDT) at my location. I was watching the western horizon, just a few degrees below Arcturus. Ursa Major was sprawled on it’s back, bowl pointing northward and the arc of the “handle” pointing down toward the west and Arcturus. Suddenly Endeavour and ISS popped into view about 15 degrees above and left of where I was focusing my attention, racing across the sky in tandem about 20 arcminutes apart! Endeavour was slightly below and ahead of the Station. What an amazing sight, seeing Endeavour flying in formation with ISS on what will likely be it’s last full day in orbit.

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