Tag: Pleiades

Fire, water, and ice

By Phil Plait | May 12, 2012 7:00 am

Because you simply cannot have enough incredibly beautiful photographs of aurorae in your life, here’s one taken near Tromso, Norway, on March 28, 2012 by photographer Helge Mortensen:

[Click to coronalmassejectenate, and you should.]

What a shot! Dead center in the picture is the Pleiades, the small cluster of bright stars. The bright object is the Moon, and to the lower right is Venus. If you look carefully, just above the horizon, lies Jupiter. To see it, start at the Pleiades, let your eyes move down and to the right to Venus, then keep going; Jupiter is in line with the clouds, just at the edge of the aurora itself.

I love how that one long swooshing ribbon of aurora cuts across the whole picture. See how it looks broader to the left, then narrower as you follow it to the right? That’s almost certainly perspective making it looks smaller. It’s probably something like 100 kilometers (60 miles) above the Earth’s surface and follows the Earth’s curve. The far end of it, near the horizon, is much farther away than the part at the upper left.

And despite all the drama occurring in the sky, my eye keeps getting drawn to the water. In this 10 second exposure, the slow movement of the water softens its appearance. Funny, too: I saw a face in the water and chuckled, then noted that Mortensen got a note from a friend who saw the face as well… or maybe a different one. But the one I see is pretty obvious. Do you see it too?

Mortensen has many more beautiful shots of aurorae on his 500px page, so head over there and soak up the glory of the active sky.

Image credit: Helge Mortensen, used by permission.

Related Posts:

The green fire of the aurora, seen from space
January’s aurora from way far north
Faith and begaurora
The rocket, the laser, and the northern lights

Stunning winter sky timelapse video: Sub Zero

By Phil Plait | March 28, 2011 11:06 am

I love all the time-lapse videos I’ve been seeing over the past few months. They show the night sky the way I see it: ethereal, mysterious, beautiful, and awe-inspiring.

Photographer Randy Halverson created this stunning video from images he took just last month in the bone-chilling winter of South Dakota. He calls it "Sub Zero". Make sure you’ve set it to show the HD version.

Amazing! I love how it starts with a Moon halo: the ring around the Moon as light from our satellite refracts through ice crystals in the air. You can see the familiar constellations of Orion and Taurus throughout the video, as well as stars like Sirius and the Pleiades cluster. Each picture was an exposure of several seconds, and in some, like the ones with the playground in the foreground, you see the blurring of terrestrial objects from the wind. [UPDATE: Randy just sent me a note; you can see animals moving in and out of the attic on the right side of the house in the playground shot. Raccoons? Well, something that can survive the temperatures. Ice warriors, probably.]

I remember when I was first dabbling in astrophotography when I was in high school. I took shots of the northern sky from my driveway, and when I developed them (yes, they were film and I used a darkroom and everything) I was deeply surprised to see the blue sky and well-lit houses and ground! But I quickly understood that these were long exposures, and any scattered light — street lights, Washington DC on my horizon to the northeast, and so on — would make these look more like daytime shots… even though you could see stars in the sky. Randy’s video (and others like it I’ve posted in the past; see Related Posts below) show the same effect. It looks like they were taken in the day, until you see the sky littered with stars.

And as much as I love big, splashy wide-angle shots of the night sky, the addition of a slowly moving viewpoint as the stars wheel overhead makes these videos even more enthralling. It’s hard to imagine a better way to show people the art and magnificence of what we see every night over our heads.

Video credit: Randy Halverson, used with permission.

Related posts:

Awesome timelapse video: Rapture
Orion in the Mayan skies
Sidereal motion
Time lapse: The spinning Chilean sky
AMAZING wide-angle time lapse night sky video!

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

The Seven WISE Sisters

By Phil Plait | July 19, 2010 7:04 am

If you live in the northern hemisphere and go outside in the winter, hanging not too far from Orion’s left shoulder is a small, tight, configuration of stars. A lot of people mistake them for the Little Dipper — I get asked about it all the time — but really it’s the Pleiades (pronounced PLEE-uh-dees), an actual cluster of stars about 400 light years away. To the eye you can usually spot six of the stars (the seventh, seen in ancient times, may have faded a bit since then), and in binoculars you can see dozens.

But when NASA’s Wide Field Infrared Survey Explorer (WISE) looked at it in February, this is what it saw:


Coooool. Literally! WISE looks in the infrared, and can see cool objects that are invisible to our eyes. The Pleiades stars are bound together in a cluster by their own gravity, and are currently plowing through a dense cloud of dust and gas in the galaxy. The material has been warmed up by the hot stars, and glows in the infrared. Deep images in visible light also show the material, but it looks blue as it reflects the optical light from the stars. In the WISE images, we’re seeing the matter actually glowing on its own, emitting infrared light.
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CATEGORIZED UNDER: Astronomy, Pretty pictures

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