Thursday, April 29, 2010

Carpe Cosmos

The universe waits for no one. Celestial events and phenomena are occurring all the time, some with more frequency than others. Astronomical objects are coming in and out of view— monthly, seasonally, cyclically.

None of these occur on your schedule or my schedule. They occur on their own schedule, on a cosmic schedule. It is up to us to make ourselves available to witness them, to be at the right place at the right time, so to speak.

You don’t necessarily need a pile of high-priced equipment to seize the cosmic moment. In fact, some of these spectacles are best viewed with the naked eye. A selection of my favorites are listed below. Pencil a few into your datebook, won’t you?

1) Total Lunar Eclipses. Lunar eclipses occur only at Full Moon. When the Sun, Earth, and Moon are aligned such that the Sun casts Earth’s shadow on the Full Moon, we experience a lunar eclipse. A lunar eclipse may be partial or total, depending upon the alignment of the three bodies. When all three line up so that the Moon is entirely within Earth’s shadow, it's called a total lunar eclipse, and the Moon turns red. Really! It’s a phenomenon that’s even visible in the city, and you won’t soon forget the eerie sight.

The next total lunar eclipse will occur on December 21, 2010. Totality begins at 12:40 a.m. Mountain Time (adjust for your time zone) and ends at 1:53 a.m. Mountain Time. It will be visible throughout North America.

You can practice with a partial lunar eclipse on June 26, 2010. This one’s pretty well placed for the continental U.S., with the exception of the East Coast. You’ll need to get up in the wee hours on the 26th and watch the Moon setting, just prior to sunrise. This is when you’ll see a portion of the Moon in shadow— at greatest eclipse, about 50 percent.

2) Meteor Showers. Comets leave behind clouds of debris when their orbits take them near the Sun. Subsequently, when Earth, on its orbit around the Sun, plows through one of these debris clouds, we experience a meteor shower.

The Perseids (PURR-see-yidds) are a reliable shower active from mid-July through the end of August. This year, they peak on the morning of August 12, 2010. The peak date, as well as a day before and a day after, are all good times to plan to view them. You’ll need to watch for them between midnight and dawn. This year should be optimum viewing, as the waxing crescent Moon will set before midnight and therefore won’t wash out the sky.

You won’t see many “shooting stars” in the city, so find yourself a dark site away from urban light pollution. A meteor shower is Mother Nature’s fireworks show. Don’t miss out.

3) Planetary Alignments. Because the planets all travel at different speeds around the Sun, they periodically catch up to one another. From our vantage point on Earth, the naked-eye planets can sometimes appear to be close to one another in the sky, as they pass. In addition, they may happen to be nicely placed near a crescent Moon, since the Moon is always changing position in our sky over the course of a month.

These picturesque groupings are called alignments, and the combination of bright objects makes an easy observing target even for city dwellers. Here are some nice upcoming alignments to watch for:

Looking west after sunset on July 31
Star maps created with
Your Sky

On July 31, about a half hour after sunset, look west for a trio of bunched-up planets: Venus (the brightest), Mars (reddish-colored), and Saturn (golden-colored). Mercury is there too, but hanging low over the western horizon, so it will be a challenge.

Looking west after sunset on August 13

On August 13, about a half hour after sunset, look west for the aforementioned trio with the crescent Moon now joining them.

4) Milky Way. You might call this one the “main event,” as the Milky Way is our home galaxy. How wicked cool is it that we can look up at the night sky any time of the year and see an edge-on view of the spiral arms of our platter-shaped galaxy? Well, that is, if we get away from city lights. Unfortunately, 20 percent of the world’s population can’t see the Milky Way from where they live, due to light pollution.

Naked eye, we see what looks like a long filmy cloud stretching across the sky, but we know it’s composed of billions of distant stars. Yes, billions! If you haven’t experienced it, get yourself out to the country immediately if not sooner, and look up. You won’t be sorry.

Thursday, April 15, 2010

Seeing Double

I must disclose that, although I like a bright double star with a nice color combination as much as the next amateur, I don’t make a habit of observing doubles. I don’t own a double-star book or atlas. I don’t work my way through double-star checklists. And unless there’s enough separation to drive a Mack truck (or the starship Enterprise) between them, I don’t get particularly excited about the challenge of “splitting” doubles with my binoculars or telescope.

Oddly, my Mrs. Magoo eyes find it easier to discern structure in galaxies than to bring stars into sharp enough focus to reveal dim companions lurking nearby or to detect that One is really Two.

But I recognize that double stars have much to offer both beginning and seasoned observers, and that there are many avid and accomplished double-star hunters out there. One of these is Dee Friesen, a New Mexico amateur.

Dee is a Vietnam veteran and a retired commercial airline pilot. “Retired” being a relative term. Dee is very active with the local children’s science center and with public astronomy outreach in the area. He recently stepped down from a two-year stint as president of the local astronomy club. In addition, he teaches college-level astronomy and aviation. In his spare time, he and his wife travel extensively.

Dee sampling a local libation in New Zealand
Image by Ruth Friesen

I caught up with Dee recently to probe his fascination with double stars.

Whassup: So, Dee, why double stars?

Dee: I can barely make out “faint fuzzies” with the size telescope I have. I can’t discern very many features, so I’m not seeing much—other than, well, it’s there.

I like double stars because I like the theory of stars and the science of them. When I look at double stars, I can see color and magnitude. They tell me what they’re made of and what their temperature is, maybe even their relative size and distance. I feel close to what I’m seeing.

Whassup: How would you compare double stars to other targets?

Dee: From a practical standpoint, I can observe double stars on nights when the seeing and transparency aren’t good enough to see other things. I also find them easier to find. Plus, there’s beauty, there’s much more variation in color intensity, their separation, the comparative magnitude. You get interesting combinations.

I kind of enjoy not observing the obvious or popular things like the dim dark fuzzies. I like to be different!

Whassup: What else would you like us to know about doubles?

Dee: There was a time when double stars were looked at a lot. Go back 100 years, and they were looked at a lot by both professionals and amateurs.

I like observing double stars because I don’t need the biggest fanciest equipment, I can do it in many places, and I don’t have to have the best sky conditions to see them.

Here are Dee’s picks for easy double stars for this time of year. If you want to give double stars a try, these are good targets for beginners. Happy hunting!

Polaris, the North Star, in the constellation Ursa Minor the Little Bear.
Telescope object. The position of the companion star rotates 15 degrees each hour, making it an excellent object to observe to detect the rotation of the Earth.

Mizar and Alcor, in the constellation Ursa Major the Big Bear.
Naked-eye object. The famous double in the handle of the Big Dipper. Also known as the Horse and Rider. Alcor is the dim companion to bright Mizar. If you can see both naked eye, you have good eyesight!

The Trapezium, in the constellation Orion the Hunter.
Telescope object. This is actually a quadruple star group in the Great Orion Nebula, the center “star” in Orion’s Sword. The four young stars, arranged in a diamond pattern, were born about a million years ago from the gas and dust in the nebula.

, in the constellation Canis Major the Big Dog.
Telescope object. The stars are yellow and blue. Known as the "Winter Albireo" (after the famous blue & gold double star Albireo in Cygnus the Swan – summer object).

, in the constellation Leo the Lion.
Naked-eye object. An easy-to-find double in the Sickle asterism.

Thursday, April 1, 2010

Tripping the Light Fantastic - Part 2

Let’s continue our trip along the Winter Milky Way, this time exploring the northern end.

1) About an hour after your local sunset time, face north. If you don’t know the cardinal directions at your location and you don’t have a compass, make note of where the sun sets on the horizon. That spot is approximately west. Stand with your left shoulder to the west, and you’ll be facing approximately north.

Star maps created with Your Sky

2) Moving up from the northern horizon, the first asterism (star pattern) you’ll spot is the House in the constellation Cepheus the King. It's a simple five-sided shape, not unlike a child’s drawing of a house. Its peaked roof is currently pointing straight up (toward the south).

3) Follow the westward curve of the Milky Way (toward the left) to find the Lazy W asterism of the constellation Cassiopeia the Queen. The W is standing on end, with the top of the W— the open end— facing right, or east.

4) Next in line on our glowing path is the asterism known as the Segment, in the constellation of Perseus the Hero. This is a curved line of six stars, oriented with its bulge protruding westward (to the left).

5) Continue a little farther along the Milky Way to finish up at the Pentagon asterism of the constellation Auriga the Charioteer. The very bright star that marks one of the Pentagon corners is the yellow-white Capella, sixth brightest star in Earth’s night sky.

6) With your head now tipped all the way back, can you spot where you left off last week when you swept up the Winter Milky Way from the southern horizon? The Milky Way is again bracketed by Taurus and Gemini, but this time Taurus the Bull is on the left (west) and Gemini the Twins are on the right (east).

Enjoy the spectacle of the Winter Milky Way through the warming spring, as it each night inches its way incrementally westward (or appears to, as the Earth continues eastward on its journey around the Sun). And don’t be sad when our friend WMW drops below the western horizon in June, because rising in the east to replace it will be another "light fantastic" we can trip together: the Summer Milky Way.