Onan Observatory

Minnesota Conservation Volunteer

Stars in Our Eyes

One dark night, this city couple went off to gaze at the heavens. They came back smitten by the stargazer bug.

By Joan Gilbertson and Gary Murphy

7 p.m. at Baylor Regional Park near Young America in southern Minnesota. Several members of the Minnesota Astronomical Society have rolled back the arched roof of the newly built Onan Observatory. Mike Kibat, the observatory guide, is readying the 16-inch telescope for an evening's public event, while society member Tom Youngblood enthusiastically discusses anything heavenly.

"I'm a newcomer to this hobby," explains Youngblood, a trim, engaging man near retirement age. "But I've started by memorizing all 88 constellations. Did you know that's the same as the number of keys on a piano?"

In about an hour, more society members and a mix of curious visitors (us included) will be treated to the first astronomical wonder of the night: a 1-day-old moon, one of the most slender imaginable arcs of moonlight. A white sliver barely noticeable against the deepening blue of the sky, it is the very edge of the moon catching the sun's light.

Just the night before, the moon rose and set with the sun, creating a moonless night, a phase known as the new moon. Here's a glorious contradiction for stargazers: The more full, large, and gorgeous is the moon, the more it obscures our view of other celestial objects.

Kibat shows slides as we wait for the sky to darken. Adults and children alike marvel at his color photos of planets, galaxies, and nebulae—huge clouds of interstellar gas and dust measuring many light-years across. "There's nothing like a dying-star nebula," he says. "It's awe-inspiring and humbling."

By 9 p.m., the sun's light has fallen significantly below the horizon, while the lights of the surrounding communities have begun to glow upward. Society members have carefully set up and adjusted their telescopes, many with a focus on Mars. In its closest approach to Earth in a decade, Mars is the "star" of the show tonight, reflecting the light of the sun.

A society member points out an actual star close to Mars and, to the naked eye, similar in appearance. Our knowledgeable friend informs us, "That's Antares," which means, in Greek, "like Mars."

This pleasant evening is our initiation into the universe of stargazing as a hobby. It's free and easily available to anyone with a pair of eyes (and for a somewhat better view, binoculars or a small telescope). Just a little information and a few star charts will allow you to enter into a fascinating activity to be enjoyed for a lifetime.
 

Notes for "Newbies"

Following our outing with the astronomical society, and all the lofty thoughts of the heavens it inspired, we began to wonder about the nuts and bolts (or should that be charts and lenses?) of pursuing amateur astronomy. Here are a few of the things we learned.

First, somewhat to our surprise, observation with binoculars was not looked down on by any of the serious sky-people we spoke to. Because of their portability and easy use, binoculars are actually recommended for beginners. Binoculars with 7x to 10x magnification and a large 50mm objective lens are good for casual use; higher power than that requires a tripod for stability.

After trying out a variety of telescopes at astronomy events and learning what to look for, a dedicated amateur will want to move up to a telescope, perhaps eventually one with a tracking system and larger light-gathering lenses or mirrors.

When deciding when to stargaze, consider seasonal benefits and drawbacks. Insects in the summer. Cold feet in the winter. No glare from snow in the summer. (The reflectivity factor of snow is considered to be 70 percent vs. just 10 percent from asphalt.) Drier air and therefore clearer views in the winter. Earlier sunsets, longer nights in the winter. Each season has its own favorite sights. Of course, for the dedicated, the hooked, the answer to when to stargaze is "Always!"
 

Top Eight Spectacles

As an amateur astronomer, you must realize that you're not looking for the huge, colorful images seen in astronomy magazines, nor for anything you've seen in a sci-fi movie. We learned about some of what is worth looking for when we attended the annual convention of the Astronomical Society of the Pacific held recently in St. Paul. Bob Berman, astronomer and popular columnist for Astronomy and Discover magazines, presented a lecture: The Greatest Sky Spectacles of the 21st Century. Here are notes on some of the most common and easy sights to see.

Moon. Earth's satellite is the hands-down winner in terms of spectacle, and a good starting place. You've likely looked at it before, as people through the ages have.

It was the huntress-goddess Diana to the Romans, a rabbit who mixes the potions of life to the Chinese, and simply a man's face looking down on Earth to many others. Observation with even low-powered binoculars reveals a landscape of mountains, ridges, seas, and craters. Anticipating the moon's phases as it waxes and wanes from new to crescent to full and back again, can be a lot of fun and a great science lesson for children. It also tells you the best time to do the rest of your astronomy.

Milky Way and Other Galaxies. The Milky Way and other galaxies are huge groups of stars, bound together by gravity. Viewing the Milky Way is a simple naked-eye experience. The tricky part is getting to a place that's dark enough to really see the river of celestial bodies in all its glory (see Light Pollution). There are likely 200 billion stars in the Milky Way, the galaxy we reside in. Observing it is just taking a peek around our neighborhood. The awe is in appreciating the fact that 200 billion is just a tiny fraction of the stars in the universe.

As majestic as galaxies are, they're often described as gray lint when first seen through a telescope. Berman warns star enthusiasts against showing Andromeda to newcomers. "Stay away from Andromeda," he says of this large spiral galaxy that is usually visible to the naked eye. "People expect a galaxy to look like the movie image. But through a telescope it's just a piece of smudge. And you're going to look like a PR person from an antimatter planet."

Stars and Constellations. One of the easiest constellations to recognize is the hunter Orion with his distinct belt of three stars, shining so prominently in the southern part of the winter sky.

As inhabitants of the North Star State, we surely should be looking for Polaris. The North Star is part of the Little Dipper, which is a part of the constellation Ursa Minor, the Little Bear, and near the Big Dipper, which is the hindquarters and tail of the Big Bear, Ursa Major. The British call the Big Dipper the Plough, and escaping slaves in the 1800s followed the Drinking Gourd north to freedom.

You can look for your own constellation of the zodiac, be it Taurus, Scorpius, Leo, Sagittarius, or one of the others.

According to a Cheyenne legend, the entire dome of the sky was considered the Great Turtle, its shell glittering with the ax heads, spear points, and skeletons of brave warriors who climbed on it.

Planets. One can usually distinguish planets from stars and other celestial objects by the fact that they don't "twinkle" as much as stars do. Look for Saturn's rings and one of its moons, Titan, the largest satellite in the solar system. In addition to Mars, Venus and Mercury can be easily observed with the naked eye. As evening or morning "stars," Venus and Mercury travel across the sky as their positions relative to Earth change. The challenge in observing Jupiter is actually discerning its Great Red Spot, a hurricanelike storm more than 15,000 miles long, first observed in 1664.

Meteor Showers. Lying on the picnic table or the dock up at the lake, marveling at a night that seemed loaded with "shooting stars," did you ever guess that there is a regular schedule for the best meteor showers, about as close to clockwork as one can get? As Earth orbits the sun, it encounters the same clouds of meteoroids—interplanetary debris—every year. The meteoroids strike Earth's atmosphere like bugs on a windshield, burning up as they enter the atmosphere.

Although the Leonid meteor shower this past November will be hard to beat, the Quadrantids will be a major event, peaking around Jan. 3 with about 85 meteors per hour. Probably the most spectacular showers in 2002 will appear from the constellation Perseus in August, peaking mid-month with 40 to 60 meteors per hour.

Comets. Comets are large masses of frozen materials (sometimes described as dirty snowballs) that travel in long, elliptical orbits around the sun. These are not the best starting point for a beginner, because they do not appear often. Two of the best came around just recently. Hale-Bopp was incredibly huge and bright, visible even at dusk in big cities loaded with light. Hyakutake had a tail stretching some 45 degrees across the sky.

Artificial Satellites. This is kind of cheating because the many communications, weather, and other satellites are not natural celestial objects. But it can be fun to spot and follow them. Look for an especially brilliant pinpoint of light that's clearly in motion.

Aurora Borealis. The northern lights shimmer and flow through the sky as if afire with vibrant red or eerie green. The aurora is the result of Earth's magnetic field being disturbed by solar storms. It is a phenomenon similar to the working of a color television: charged particles glow different colors, depending on their chemical makeup. Aurora borealis occurs around the north magnetic pole. It is produced in the outer atmosphere when atomic particles strike and excite atoms.

The past several years have been particularly strong in solar activity. Living in a northern latitude, Minnesotans have a great seat for the show. According to Berman, the most mind-boggling display of the aurora comes the year after strong solar storms. This March, northern lights are expected to be particularly spectacular.
 

Any Questions?

Why, of course you have questions. Aspiring amateur astronomers realize that looking at the stars, planets, galaxies, and other celestial phenomena is only part of the experience. There's always more to know (see Cyberspace Stargazing and Astronomy Events). There are the charts, telescopes, and other gadgetry to be mastered; the cycles of the planets, constellations, and meteors to be learned; the mathematics of distances and magnitudes to be calculated; the causes of astrophysical phenomena to be studied; the literary and mythological significance of the heavens to be pondered. And on top of all that, there's always the opportunity to go out and share the pleasure of hobby astronomy with other stargazers!

Light Pollution: Might I See a Star Tonight?

The night sky and the heavenly bodies that populate it have long served as poetic symbols of eternity, permanence, and infinity. So it's difficult to think of a starry night as a resource that could fade, even disappear. Sadly, though, for modern stargazers—whether professional astronomers or hobbyists—there has indeed been a loss in the night sky. This has come by way of a problem any one of us may innocently contribute to: light pollution.

Astronomers have long recognized that residential and commercial development is eating away at the darkness, diminishing the night sky. Much of the problem is due to poorly designed lighting, which causes "light trespass" (light shining outward and upward where it is wasted) and glare (light brighter than our eyes can process).

"The amount of wasted ‘up' street light in the U.S. could provide all the electricity for a country the size of Ireland or Israel," says International Dark-Sky Association member Daniel Brocious. The association estimates that up to 30 percent of outdoor lighting in the United States is wasted, at a cost of more than $1.5 billion annually.

Many sky watchers worry that today's children will never have the opportunity to fully appreciate the beauty of the stars because of this polluting washout.

Fortunately, there are hints of a brighter future for dark skies. Concerns about the cost and availability of energy have encouraged many municipalities to focus on turning down the lights, thereby turning up the stars.

The Dark-Sky Association is educating consumers, businesses, and government about the benefits of switching from inefficient mercury vapor lights to lower-wattage, low-pressure sodium bulbs. The association also recommends using full-cutoff lighting fixtures that emit no light above the horizontal plane rather than unshielded "glare bombs." More than 100 cities and counties, plus a handful of states, are implementing these simple, inexpensive modifications to diminish light domes around developed areas.

"This is truly a solvable environmental problem," says Brocious. "It's not like trying to remove all the styrofoam peanuts from the ocean."

Joan Gilbertson

Cyberspace Stargazing

astro.umn.edu/Outreach/pub_out.html This University of Minnesota Department of Astronomy web site has information about public outreach programs and links to various sky charts and maps, as well as images from the Hubble space telescope.

astronomy.com/ This Astronomy magazine site offers science and feature stories, great photographs, and a special section for kids.

darksky.org The International Dark-Sky Association site has information related to its goal: "To preserve and protect the nighttime environment and our heritage of dark skies through quality outdoor lighting."

fourmilab.ch/yoursky/ This site allows you to enter your longitude and latitude to get a virtual view of the night sky in any direction.

lightpollution.it/dmsp Based on satellite data and other calculations, this world atlas of artificial night sky brightness—by Pierantonio Cinzano, Fabio Falchi, and Chris Elvidge—shows the extent and severity of light pollution.

mnastro.org/onan/events.htm Minnesota Astronomical Society announces the Onan Observatory's "star parties" and other news.

skypub.com/ Produced by Sky & Telescope magazine, this site has expert advice for backyard stargazing, as well as weekly and monthly sky charts.

Joan Gilbertson

Astronomy Events

The night sky is the focus of attention at the following events and activities this winter and spring.

Hennepin Parks: Our Winter Sky, Jan. 10, 9 p.m., Eastman Nature Center, Osseo; Star Gazing, Jan. 18, 7 p.m., Cleary Lake Regional Park, Prior Lake. Register early for either event by calling 763-559-6700.

Minneapolis Planetarium: Winter Star Show, Jan. 12­April 18; programs include Space Dreams, Dinosaurs in the Dark of Night, There's No Place Like Space, Follow the Drinking Gourd, and Romancing the Stars. Call 612-630-6155.

Minnesota Astronomical Society "star parties," viewing events for the public: March 1 and 29, Metcalf Nature Center, Afton; March 8, Cherry Grove Observatory, south of Cannon Falls; March 15, Baylor Regional Park, Young America. If weather prevents viewing for a Friday star party, viewing is rescheduled to Saturday. To confirm viewing conditions or for directions, call the society at 952-467-2426.

Minnesota Valley National Wildlife Refuge: There's a Bear in My Sky! Learn how prehistoric people viewed the night sky, Jan. 23, 7­8:30 p.m., Bloomington, 952-854-5900.

University of Minnesota Department of Astronomy: public viewing Fridays, 8­9:30 p.m. weather permitting, Tate Laboratory of Physics, Minneapolis, 612-624-3859; public tours of 30-inch telescope by appointment, O'Brien Observatory, Marine on St. Croix, 612-624-7806.

Joan Gilbertson, former DNR video news producer, is a news producer for WCCO television. Gary Murphy is a copywriter for The Sportsman's Guide catalog.