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9 posts from February 2011

02/25/2011

Constellations That Aren't

2-25-11 Starry Night over the Rhone van Gogh
Vincent van Gogh's Starry Night over the Rhone

As kids, the Big Dipper is usually the first pattern of stars we learn to pick out in the sky. But the Big Dipper is not a constellation. The Big Dipper is just a portion of the constellation known as Ursa Major the Great Bear. The astronomical term for any star pattern that is not a constellation is “asterism”. Asterisms can be like the Big Dipper, where they are formed from a portion of a constellation, or they can be stars from multiple constellations.

The Big Dipper is the part of the Great Bear that forms the back half of his torso and his abnormally long tail. Look in front of the bowl of the Big Dipper to find the rest of the bear’s body and his triangle head. The legs can also be found extending below the body.

Another famous asterism visible in the evening sky at the moment is the Sickle. The Sickle’s curved shape makes it look distinctly like a backward question mark, and it marks the head of Leo the Lion. This weekend, the Sickle can be found in the east after sunset. The brightest star of the Sickle is Regulus at magnitude 1.4. It marks the point at the bottom of the question mark. Rising behind the Sickle is the rest of Leo the Lion’s body, which is formed by three stars in a triangle.

Some other asterisms are

  • The Summer Triangle
  • The Winter Hexagon
  • The Great Square of Pegasus
  • The Northern Cross
  • The Teapot
  • The Coathanger

Learn more details about some popular asterisms and what time of year they can be spotted.

-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She is currently the Feature Writer for Astronomy and Space at Suite101.com. You can follow her on Twitter at twitter.com/Astronomommy.

02/24/2011

Year in Yosemite: Let it Snow

DSCN1525

When I woke this past Sunday morning I discovered snow covering the trees, the road, and the ground, so I did what I always do when faced with a snowstorm. I jumped up from bed, ran downstairs to turn up the heat, made a beeline for the coffee maker and prepared breakfast, even though no one else was up. Because snow in Yosemite National Park means many things — a winter wonderland for visitors, a deeper snowpack in the high country, better skiing at Badger Pass and more accidents on the road. But at our house it means only one thing — if the electricity isn't out already, it will be soon.

After a year of living in Yosemite, I have an almost reflexive reaction to the white stuff. I do what's important and I do it fast because it's only a matter of time until it's cold and dark.

Continue reading "Year in Yosemite: Let it Snow" »

02/17/2011

By the Light of the Full Moon

Porchlight and Moon niemisensa

A porchlight mimics the moon in Lapland. Credit: Sami Nieminen

The date of the full moon and the evenings surrounding it have never been considered good times to stargaze. Fainter objects are washed out by the brilliant glow of the moon, and even looking at the moon itself provides only a flat view, without the terminator to bring out the sharp edges of the lunar topography.

Yet, there are still interesting things to consider when gazing at the eye-catching full moon as it crests above the horizon. Every full moon has been given a multitude of nicknames by Native Americans, Chinese, colonial settlers, and so forth. This month, the full moon occurs at 12:36 a.m. PST on Friday, February 18. February’s Full Moon is sometimes called the Snow Moon. When a full moon’s glow is reflected off the snow, the evening can be bright enough for an evening stroll. (If only it weren’t so cold out.)

If you have clear skies and can see the moon over the weekend, here are a couple things to consider. On February 19, the moon will be in perigee, lying 222,604 miles from Earth, its fifth closest of the year. (Next month the full moon and the closest moon occur on the same day.) As you gaze upward, try to get a feel for the size of this orb suspended in space. It can be tricky when there is nothing tangible to compare it to, so consider this: The moon has a diameter of about 2,160 miles. The continent of Australia is nearly the same distance across. (From Perth on the west coast to Sydney on the east coast is a span of 2,045 miles.) So as you look up at the full moon, imagine Australia stretching across the face of it to give you an idea of its size.

Now, what do you imagine it would feel like to be up there on the moon? If you’re standing outside on a chilly February night, gazing into the darkness, it’s easy to believe that the air up there would feel very frosty. But it’s a bit of a trick question, because there is no atmosphere on the moon. However, there is still a surface temperature. If you were standing on the surface during full moon and bathed in all the sun’s light, it would be 253 degrees Fahrenheit. Which, I think it’s fair to say, is hotter than it looks. If you were standing on the opposite side of the moon at this time, far from the sun’s rays in the darkness, the temperature would only be -243 degrees Fahrenheit. Which makes standing outside in February and gazing at the Snow Moon seem not such a chilly undertaking after all.

-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She is currently the Feature Writer for Astronomy and Space at Suite101.com. You can follow her on Twitter at twitter.com/Astronomommy.

Winter at the National Arboretum

For a sketchbook artist, silhouettes are the subjects of winter. With two months to go before bloom, the curved and twisted branches of this weeping cherry tree make their own pattern against the pale winter sky:

Art_branches

At the National Arboretum in Washington, D.C., the winter landscape has a subtle beauty. I found the weeping cherry there yesterday and, with my mittens on, drew three of the U.S. capitol's 20 original columns, perched in the meadow and waiting to surround a new building:

Art_pillars

If you go to the arboretum in February, you may see the first two trees of the blooming year: the scented Japanese apricot (Prunus mume) and the witch hazel (Hamamelis x intermedia).  The cold has kept both of these trees from putting on much of a show yet. Disappointed by this sad fact discovered on my recent visit, I turned to the evergreens in the Gotelli Collection at the arboretum. Most of us have room for only one or two ornamental evergreens, and we often think of them as screens in the residential landscape, arranging them in static rows. A slow-growing green tree without flowers, fruit, or much fragrance, it has an image problem to overcome.

But not at the Gotelli Collection. Here, evergreens have grown into their mature, graceful shapes, surrounded by plenty of open space. These evergreens are the stars of the late-winter arboretum:

Art_trees

-- Sue Fierston paints and teaches just outside of Washington, D.C. in the Chesapeake Bay watershed. As a painter, she works in acrylics and watercolor and is in the middle of a series called "100 Flowers." As a teaching artist, she works with teachers to bring art into their classrooms in grades 4-8. Her posts focus on her nature-themed art collaborations. For a look at her paintings or more about her teaching, check out her website at suzannefierston.com.

02/15/2011

Year in Yosemite: Worth the Wait

  DSC_1875

When I met the man who is now my husband, we started out our relationship very slowly. Some hikes, some dinners, a concert here or there. We spent a lot of time as friends, kind of, sort of hanging out together. Then, suddenly, one day, without either of us really understanding the how or why of it, we became a couple. How fitting then that we should spend Valentine's Day making plans to attend the Firefall Event near our home in Yosemite National Park. Because sixteen years ago, when I was wondering just what I was doing in this relationship, a very wise friend said, "Better a trickle to a waterfall, than a waterfall to a trickle."

Prior to meeting Jon, all of my relationships had been like the man-made firefall that wowed visitors to Yosemite for 88 years. A massive bonfire of red fir bark that was pushed off Glacier Point at 9 p.m. each summer night, it would light up the cliffs in a dazzling display, but by the time it hit the ground, it was just embers. That firefall was stopped by the park superintendent in 1968, cited for causing too much congestion as well as for being "unnatural and unnecessary."

Continue reading "Year in Yosemite: Worth the Wait" »

02/10/2011

Astronomy: Draw Your Own Constellation

Heart Nebula

The Heart Nebula in Cassiopeia. Credit: Hunter Wilson

I was at my children’s school today, shelving books for next week’s book fair. One of the books for sale, The Curious Incident of the Dog in the Night-Time, is a favorite of mine. In the book, the main character, an autistic boy named Christopher, often thinks about astronomy and space. In one instance, he says, “People say that Orion is called Orion because Orion was a hunter and the constellation looks like a hunter with a club and a bow and arrow … But this is really silly because it is just stars, and you could join up the dots in any way you wanted, and you could make it look like a lady with an umbrella who is waving … And there aren't any lines in space, so you could join bits of Orion to bits of Lepus or Taurus or Gemini and say that they were a constellation called the Bunch of Grapes….”

Christopher’s right. The stars in the sky can be whatever constellation you want them to be. Even though the constellations were named thousands of years ago, there have been changes through the years: some added, some taken away, some split into new constellations. And there’s nothing that says you can’t create your own constellation. It may not be officially recognized, but it will make for a one-of-a-kind Valentine’s gift.

This Valentine’s evening, take your special someone outside (and it is supposed to be warmer across much of the US on the 14th!) and show the stars to your beloved. You might want to plan ahead and do a little stargazing before that night, so you have an idea of just what your constellation will be. Make up shapes and stories for something that has meaning for the two of you. Cassiopeia could be an E, M, or W. Gemini the Twins could be two sweethearts holding hands. Be creative and find your own story.

For those of you who are more traditional, you can view the Heart Nebula this Valentine’s weekend. Located in the constellation Cassiopeia, the Heart Nebula (IC 1805) is magnitude 6.5 and visible through moderate telescopes. A cluster of stars at the center creates the red glow. This “heart” lies 7,500 light-years away. A bonus nebula lies to the left of the heart. This is IC 1848, the Soul Nebula. The Heart and Soul Nebula would be a unique way to end a great date.

-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She is currently the Feature Writer for Astronomy and Space at Suite101.com. You can follow her on Twitter at twitter.com/Astronomommy.

Year in Yosemite: Heaven Sent

Mosquito_small

The garden of our house in Los Angeles has about ten fruit trees. All of them produce wonderful, juicy, natural wonders such as plums, peaches, oranges, limes, tangerines, figs and grapefruit. Our yard also has two ash trees. And if it’s been a particularly cool year, they drip with a nasty rain of honeydew. Not honey dew as in melon, but honeydew as in sticky, messy, runny gook that’s all but impossible to scrub off of windshields, patio cushions, furniture and sidewalks. The first time it fell in sleet-like drops we called in an arborist to see if the tree was sick. It wasn’t. It was just infested with aphids. And like bees collecting pollen to make honey, these tiny little insects were happily making honeydew up in our trees.

Continue reading "Year in Yosemite: Heaven Sent" »

02/08/2011

Nature Art: Color, or No Color?

Swine flu
Photo by Luke Jerram

When artists interpret nature, the results can be beautiful. Sometimes that interpretation includes color, and sometimes it doesn't.

British artist Luke Jerram works in glass, sculpting viruses and bacteria with the help of other scientists and glassblowers. The photo above shows several of his glass viruses; the largest sphere, measuring about eight inches in diameter, is swine flu.

Here is E. coli, supersized 500,000 times:

E. coli
Photo by Luke Jerram

This horseshoe crab-like sculpture is actually three feet long. Jerram keeps the scale of the original virus or bacterium but enlarges its size to help us see the complexity of these microorganisms. And, he uses no color in his glass. He says, "If some images are coloured for scientific purposes, and others altered simply for aesthetic reasons, how can a viewer tell the difference? How many people believe viruses are brightly coloured?"

He goes on to say, "...what kind of ‘presence’ do pseudocoloured images have that ‘naturally’ coloured specimens don’t?"

Felice Frankel, a photographer and senior fellow at the Institute for Innovative Computing at Harvard, believes in using color: "To me," she says, "the idea is to engage somebody to look at something." Frankel photographs objects on the nanoscale and colorizes her images to teach us how these tiny objects work. She's written three books that capture her images on this microscale: Envisioning Science, No Small Matter, and my favorite, On the Surface of Things.

In this video, she explains the techniques she uses to color her photos.




What do you think? Do these changes in actual size and color help you understand what you are seeing?

-- Sue Fierston paints and teaches just outside of Washington, D.C. in the Chesapeake Bay watershed. As a painter, she works in acrylics and watercolor and is in the middle of a series called "100 Flowers." As a teaching artist, she works with teachers to bring art into their classrooms in grades 4-8. Her posts focus on her nature-themed art collaborations. For a look at her paintings or more about her teaching, check out her website at suzannefierston.com.

02/03/2011

Astronomy: Understanding the Magnitude of it All

2-4-11 orion Phil Massey, Lowell Obs.NOAOAURANSF
The stars of Orion are part of the winter hexagon. Credit: Phil Massey, Lowell Observatory, NOAO/AURA/NSF

Each season holds different meaning for stargazers. Spring is notable for the wide expanse of galaxies that can be viewed in the evening sky. Summer is popular for viewing the Milky Way. Fall brings famous star clusters into sight. And winter is known for having the largest collection of bright stars.

Stars are assigned a magnitude based on how bright they are. This classification system has been around for thousands of years. In ancient Greece, stargazers identified the brightest stars they saw and labeled them as 1st magnitude. Stars that were two-and-a-half times dimmer were considered 2nd magnitude, and stars two-and-a-half times dimmer than that were 3rd magnitude, so on.

The winter hexagon and winter triangle are two targets to view that will help you compare some of the brighter stars. Sirius, the brightest star in the heavens, lies at the bottom of the winter hexagon and shines at magnitude -1.4. Sirius is a first magnitude star because it has a magnitude of one or brighter. Follow the link above to learn the other stars in the winter hexagon: All of them are first magnitude stars.

An example of a 2nd magnitude star would be Polaris, the North Star. Compare Polaris with the stars of the winter hexagon to see how the brightness drops off. Polaris is the last star in the handle of the Little Dipper. Look to the opposite side of the Little Dipper, to find the star in the bowl that is farthest from Polaris. This star is 3rd magnitude Pherkad. (The other star on the far side of the bowl of the Little Dipper is 2nd magnitude Kochab.) The two other stars in the handle of the Little Dipper and the first star that connects the handle to the bowl of the Little Dipper are all 4th magnitude stars. In light-polluted locations, these stars may be difficult to see. The remaining star that marks the other corner of the bowl of the Little Dipper is just at the threshold of 5th magnitude.

-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She is currently the Feature Writer for Astronomy and Space at Suite101.com. You can follow her on Twitter at twitter.com/Astronomommy.


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