Great space sights & sites

November 01, 1999|By Frank D. Roylance | Frank D. Roylance,Sun Staff

You don't have to buy a telescope to tour the universe. You don't even have to stand for hours in your freezing back yard to see cool stuff in the night sky.

There is a galaxy of astronomy Web sites on the Internet. Some offer the latest, most beautiful images from the Hubble Space Telescope, and from spacecraft circling Jupiter and Mars.

Others make it easy to predict when you can step out on your sidewalk for a few minutes to watch the space shuttle, the International Space Station (ISS) or Russia's Mir space station cruise over your head.

It's good fun for students, families and the neighbors' kids. One night I even persuaded my wife to jump in the car, in her nightie, to drive a few blocks with me to watch sunlight flare off an Iridium communications satellite. She loved it. Really.

A good place to start is the Hubble Space Telescope's "Heritage Project" site. Point your browser to http://heritage.stsci.edu. Then click on "Gallery of Images" and behold some of the most beautiful and eerie outer-space images ever snapped. There are gorgeous, sharply detailed spiral galaxies; glowing "globular" clusters of stars; colorful gas nebulas; and majestic planets.

From the home page, click on "Hubble Heritage," then on "About the Hubble Heritage Images," and finally on "Is that what they really look like?" You'll find a revealing tutorial on how astronomers use false colors and computer enhancement to concoct their final images.

Their goal is to reveal and highlight physical processes, not to duplicate human vision. Those weird pillars of dust, gas and infant stars in the Hubble's famous Eagle Nebula photo look almost nothing like they would to our eyes, but who cares? They're gorgeous, and they have a lot to teach us. The Hubble Heritage people add a compelling new image every month.

Now for some real backyard astronomy. Send your browser to www.heavens-above.com.

When it pops up, the program will need your longitude and latitude so it can tailor its predictions for you, and not some guy in Bolivia. Click on "selecting from our huge database." Then click on your country, and type in your community. The program will calculate the coordinates for you.

Be specific. It knew the difference between Cockeysville and Hunt Valley. If there's more than one town by the same name, you'll get a list of choices. Click on yours. That takes you to the main page. Bookmark it, and every time you go back it will remember your coordinates.

Now the cool part. On the main page, you can call up fly-by predictions for a variety of satellites. Best bets are the Russian Mir space station (until it crashes next winter), the ISS, and the Iridium flares. They're all big and bright and hard to miss.

For starters, click on the 10-day predictions for the ISS. On the screen you'll find a list of visible passes by the space station, telling you when and where to look. The dates are easy enough, but the rest may need some explaining.

Mag: The magnitude, or how bright the satellite will appear. Satellites reflect sunlight, and their brightness depends on the sun's angle and their own shininess. Important: The lower the values (including negative numbers), the brighter the satellite will appear.

Starts: These columns tell you where and when the satellite will appear first. All times are military (6 a.m. is 06:00 hours; 6 p.m. is 18:00). Elevation (El.) means how far above the horizon in degrees to look. (Zero is on the horizon; 45 is halfway up the sky, and 90 is directly over your head). Azimuth (Az.) is the compass direction.

Max. Elevation: The highest the satellite will appear in the sky, and when, in degrees. The bigger the number, the easier it may be to spot.

Ends: The time and place where the satellite disappears. In the evening, they wink out when they fly into the Earth's shadow.

Some quick tips: Buy an inexpensive compass. I was surprised to learn where north really was. Go outside a couple of minutes early to get oriented. You will need a fairly broad view of the sky, especially if the predicted elevation is low. Compare start and end times; at 18,000 mph, these flyovers last just a few minutes, and the best are the longest ones.

A satellite looks like a moving "star" that shines with a steady white light. If it's flashing, or has a red light, it's likely an airplane. You'll also need a clear night. Suburban light pollution shouldn't hurt, but city lights may obscure the view.

The Iridium satellites are different. Iridium is a constellation of 66 telephone communications satellites in polar orbits. The company is in financial straits, but its birds fly on.

The Iridium spacecraft have mirrorlike antennae that happen to reflect sunlight to the ground in highly predictable patterns. To the observer, the reflection appears like a flare that appears suddenly in the dark sky, brightens to astonishing brilliance, then fades and disappears. They're often mistaken for airliners' landing lights or UFOs.

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