The International Space Station (ISS) is back at dawn for the next few weeks. If you’re up early, take a look at the brightest satellite of them all. On good passes the ISS is nearly as bright as Venus in the western sky right now. From its vantage point 240 miles above the Earth, the astronauts must have had fabulous views of northern lights these past few weeks. Unfortunately I can’t find any good recent pictures, but the one above, taken on January 25, reminds me of looking down on the clouds from a mountaintop – only it’s aurora!
The bottom edge of a typical aurora is about 60 miles high (rarely 50 miles during intense storms); the top about 200 miles but occasionally reaching up to 350 miles. “We can actually fly into the auroras,” said NASA astronaut Don Pettit in a recent article on Space.com, a space station flight engineer for the current Expedition 30. “It’s like being shrunk down and put inside of a neon sign.”
Viewing times for the space station below are for the Duluth, Minn. region. To find exact times when the space station will pass over your town, log on to Heavens Above or type in your zip code on Spaceweather’s Satellite Flybys page. The ISS looks like a brilliant star moving from west to east and takes about 4 minutes to cross from one side of the sky to the other.
* Mon. March 19 starting at 5:19 a.m. Appears very low in the southeastern sky
* Tues. March 20 at 5:56 a.m. Much easier to see! Bright pass across the south
* Weds. March 21 at 6:34 a.m. Brilliant pass nearly overhead
* Thurs. March 22 at 5:40 a.m. Another fine flyby high in the south
* Fri. March 23 at 6:17 a.m. Bright pass across the northern sky. Zips just above the North Star.
* Sat. March 24 at 5:21 a.m. Reappears from Earth’s shadow below the Big Dipper and moves straight across the top of the sky.
A new bright supernova was discovered on March 14 very near the center of the barred spiral galaxy NGC 4790 in Virgo. Called SN 2012 au, amateur astronomers with 8-inch telescopes or larger can get a good look at it in the southeastern sky starting around 11 p.m. It’s currently magnitude 12.7-13.0 and with the right instrument can’t be missed. I easily spotted it two nights ago at low power in my 15-inch. A sharp-eyed observer might snag it in a 6-incher especially if it continues to brighten.
The “new star” radiates like a tiny beacon at almost the exact center of the galaxy, far outshining the millions of stars in its nucleus. In the photo above, the nucleus is the little dot just to the right of the supernova.
2012 au is classified as a Type Ib supernova. Before it imploded and then exploded, it was a massive supergiant star that blew off its outer hydrogen atmosphere, exposing an interior rich in more complex elements like helium, carbon and oxygen. Fortunately for skywatchers, most huge stars end their life in spectacular fashion after exhausting the fuel in their cores.
With no heat pressure from nuclear burning to fend off gravity’s hand, the star collapses in a matter of seconds. As matter falls toward the supergiant’s core, it creates a powerful shock wave that rebounds and rips the star apart in one fantastic explosion we see as a supernova. For more information on SN 2012 au and other recent supernovae, stop by Dave Bishop’s Latest Supernovae site.