The Annular Eclipse

Will you be checking out the upcoming annular eclipse?  If so, you’ve probably heard all the safety warnings about not looking directly at the Sun. They’re good advice. When I was a kid I remember some eclipses occurring and being told not to look at the Sun. Of course, I did.  Luckily, I didn’t get any severe eye damage — but it’s worth saying again that even a little sungazing without proper protection is too much. So, if you’ve got eclipse glasses, use ‘em!  There’s no substitute for safety.

If you’re planning on viewing the eclipse, check here or here for the latest info on where the path of totality is, and what you can expect to see.

A view of a solar eclipse in 2011, caught by the Hinode satellite. Courtesy JAXA/NASA.

The joint JAXA/NASA Hinode mission will also observe the eclipse and provide images and movies that will be available on the NASA website.  Due to Hinode’s orbit around the Earth, Hinode will actually observe 4 separate partial eclipses. Scientists often use an eclipse to help calibrate the instruments on the telescope by focusing in on the edge of the moon as it crosses the sun and measuring how sharp it appears in the images. As an added bonus, the satellite’s x-ray telescope will be able to provide images of the peaks and valleys of the lunar surface silhouetted against the glow of the solar corona.

You may be wondering what an annular eclipse is. It’s simply an eclipse where the Moon’s apparent size isn’t big enough to cover the Sun as the Moon moves between Earth and the Sun. It only covers a portion of the Sun. For people in the path of totality, they’ll see a ring of light around the Moon. Those not in the path will see only a part of the Sun’s light blocked. No matter what portion you see, though, the sunlight will be too bright to look directly at the event.

That’s why you need eye protection — and by that, I mean more than sunglasses. You need eclipse shades. Your local planetarium or science center may have them, so if you’re planning to watch the eclipse, check it out.

You can also watch the eclipse via pinhole projection — that is, shining light from the Sun through a pinhole in a piece paper — and letting it shine onto a wall or another piece of paper. The image on the second surface will show you the eclipsed Sun.  It’s just about foolproof! For more details on that, check out this page from the Exploratorium.   Whatever you do, have a safe solar eclipse viewing experience. It’ll be good practice for the Transit of Venus in June!

It’s Not Planet X, That’s for Sure

Astronomers and planetarium folk have been getting the usual phone calls about “something bright in the West” after sunset.  It’s true. There is something bright out there… but it’s disappearing fast.  It’s the planet Venus, and it’s sinking lower into the western sky each day, and brightens up the post-sunset sky like a jewel hanging there against the dusk.

I love going out to look at Venus. It’s really quite beautiful, and it’s easy to understand why some early observers would call it a goddess. It just gleams in the sky.

Venus looks bright because it’s a cloud-covered world, and those clouds reflect sunlight. Also, it’s a bit closer to us in its orbit right now, and thus appears bigger and brighter.

Venus has a long history in science fiction of being a swamp world or a desert world.  I remember reading some early science fiction where people from Earth were eking out a living among dinosaur-type creatures.  Another book in my library, written in the late 50s, had Earthlings settling on a dry and dusty cloud-covered Venus, and ultimately launching attacks on Earth.

Those stories were WAY off the mark however. In the 1960s, we sent our first probes to Venus, and right away discovered the truth: a world with a poisonous atmosphere that is so heavy it destroyed the probes that landed on the planet. Later on, orbiters such as the Magellan mission mapped the volcanoes of Venus, showing us once and for all that our “sister planet” is not a very hospitable place.

But, or course, you don’t see that when you gaze at the orb of Venus hanging low in the western sky these May nights. That doesn’t make it less lovely to ponder as the sky darkens.   Before too long, Venus will be a morning object, right after it transits the Sun on June 5/6.  So, go check it out. Here’s a map to get you started!

Look for Venus low in the west after sunset for the next few weeks before it disappears in the glare of the Sun.

They’re Up There: You Can’t Miss Them

The May night skies, with Saturn and Mars.

The planets Mars and Saturn are gleaming up there in the sky these May nights.  Saturn is in the constellation Virgo, not far from the bright star Spica. I’ve seen a lot of images people are posting of Saturn, and the rings are standing out. So, if you have a decent pair of binoculars, or even better, a small telescope, you can spot those rings yourself.

When I was a kid, one of the first images of a planet I saw was of Saturn. Those rings absolutely mystified me. They were the most alien thing I could think of “out there” and I often wondered how such things could form. Astronomers knew the rings were made up of particles, but it wasn’t until the Voyager mission to Saturn that they knew just how complex the system really is. And, of course, the Cassini Mission is taking their understanding to new heights.  You can find some gorgeous views of Saturn from Cassini at the mission Web site, and I think they’ll whet your appetite to see the planet for yourself.

Mars is close to the bright star Regulus, in the constellation of Leo the Lion. It’s a reddish-looking blob of light and if you have a fairly powerful backyard telescope, you can make out some of the surface markings (dark and light) on the planet.  Of course, the best way to look at Mars (after you’ve spotted it in your night sky) is to surf over to NASA’s Mars site, or ESA’s Mars Express page.  There, you’ll find many fascinating images of the Red Planet taken by spacecraft visiting the planet “up close and personal”.

Go out these May nights and check out the planets. They’re not hard to find and they’ll pique your curiosity. I guarantee it!

Test Your Eyes with Alcor and Mizar

The Big Dipper as seen from Kalalau Valley, Hawai'i. Courtesy User: gh5046; used under a Creative Commons ShareAlike License. on Wikipedia.

The Big Dipper is one of those constellations we all learn (in the Northern Hemisphere) pretty early on. It’s easy to spot, it’s a shape that most of us recognize — even if some of us in Europe and other regions call it a Plough. It’s a pattern that we use to teach people how to find other things in the sky, such as the star Arcturus or the North Star (Polaris).

Of course, the Big Dipper is part of a larger constellation called “Ursa Major” which is Latin for “Greater Bear”.  The Dipper forms the back and tail of the Bear, and there are tales across many of the world’s cultures about this Bear and its exploits.  Most of us don’t look for all the stars of the bear, preferring to concentrate on the Dipper itself.

If you look at the Big Dipper’s handle, there’s a double star you can spot with your  naked eye (provided you have a good dark viewing area).  If you live in a city, you can probably spot the double with binoculars or a small telescope.

Those two stars are called Alcor and Mizar and for many years, people would use the ability to spot these two without magnification as a test of their eyesight.  They lie about a light-year apart and they are moving together through space as part of a larger group of stars called the Ursa Major Moving Group.

As it turns out, when you look at Alcor and Mizar, you’re looking at a six-star system. Alcor itself is actually two stars called Alcor A and B, and Mizar is really a system of two binary stars (making four total stars for Mizar).   It’s worth checking out and the weather this time of year is great for kicking back and seeing if YOU can make out Alcor and Mizar with your naked eye. (You won’t find the other stars without some major magnification, but that’s okay.  The objective here is to see what you can find just by taking a gander at the bend in the Dipper’s handle. Check it out!