Low-Light Adjustment

You have some learning to get under your belt, but right now, neophyte that you are, you can do something to enhance your experience. Unless you are looking at the bright moon, don’t rush to the eyepiece until you have allowed your vision to become “dark adapted.” This natural adjustment will greatly enhance your ability to see faint objects—and it will make brighter objects that much more exciting. Adapting your eyes to the dark requires about 15 minutes away from sources of light. If somebody shines an uncovered flashlight in your eyes, you’ll have to become dark adapted all over again. Red light, however, will not reverse dark adaptation. For those on liberal budgets, there are specially made, compact flashlights with red bulbs. For the rest of us, either equip your flashlight with a dark red filter (you can use red acetate purchased from a hobby shop) or (less effectively) simply put a red sock over the flashlight. This way, you’ll be able to see what you are doing and even consult star maps without spoiling your dark adaptation.

Learning to See

Understandably, you will be eager to try out your new telescope. Here are a few words of advice: Expect to be thrilled—immediately—by the spectacle of the moon, with its sharply delineated craters and mountains. Point your telescope elsewhere, however, and you may be disappointed—at least until you learn more about what to look for. We have become spoiled by dazzling images from the Hubble Space Telescope, orbiting above our atmosphere and toting the most sophisticated instruments available. No, your telescope won’t duplicate the performance of Hubble. But the point is that it is your telescope, and the photons of light that left the Orion Nebula are striking your retina. The experience is yours.

Your first impulse may be to blame any disappointment you feel on your telescope. Resist the impulse. As you learn what to look for—and as you come to appreciate the significance of what you see—you will derive great satisfaction from your instrument.

The Race to Save the Hubble Telescope

ABC News has been given unprecedented access to the astronauts, scientists and engineers involved in the intensive — and some say risky — shuttle mission to repair the Hubble Space Telescope later this year.

Time is running out for Hubble. If its batteries and gyroscopes aren't replaced soon, the most famous of space telescopes will simply quit functioning.

If all goes well, the Space Shuttle Atlantis mission, dubbed STS 125, will launch in August to service Hubble. ABC News will follow the crew as it trains for this mission.

This will be the last time a space shuttle visits Hubble. Everyone involved knows they must make every single minute of the mission count to ensure Hubble will continue to explore the universe until the replacement Webb telescope can be launched sometime in the next decade.

What makes this mission risky?

Unlike most recent shuttle missions, this one will not be docking at the International Space Station. If Atlantis encounters an emergency, Hubble's orbit is so far from the space station, that the Atlantis crew will not be able to reach it.

But NASA is ready with an unprecedented backup plan. For the first time, when the Atlantis astronauts launch to repair Hubble, a second shuttle will already be on the other launch pad at the Kennedy Space Center, ready to go within days if its colleagues on the Hubble mission encounter a problem.

It is easy to see why the Hubble mission is the most talked about mission of the year at NASA and overshadows the global effort to build the International Space Station.

Hubble is the telescope that can look back in time; the space station is still a construction project, albeit one of the most complicated ever undertaken.

Just what kind of allure does the Hubble Space Telescope have that the International Space Station doesn't? Apollo 7 astronaut Walt Cunningham says it's all about perception.

"The International Space Station is the most incredible engineering achievement in history. It exceeds the Panama Canal or the pyramids if you will, but it doesn't capture the public's fancy, because it looks like a truck driving back and forth delivering construction materials," he said.

Hubble was deployed in 1990, and it wasn't an instant hit. Its first images were blurry because of an embarrassing failure to notice that the shape of the telescope's primary mirror was not accurate.

A daring space shuttle mission to install corrective lenses fixed that in 1993. That troubled beginning is part of its mystique, according to Sandra Faber of the University of California at Santa Cruz.

"It was such a disaster, but it was like chestnuts pulled out of the fire at the last minute. It is the ultimate American can-do story," she said.

And oh what Hubble can do! Hubble has allowed scientists to estimate the age of the universe — 14 billion years.

Faber points to Hubble's discoveries about galaxies. "First and foremost for me as [a] student of galaxy formation, Hubble was the first telescope to look back in time and show us infant galaxies, in the process of being born. That's a first. To use a telescope as a time machine looking back billions of years — that is a terrific legacy."

Matt Mountain, director of the Hubble Space Telescope, says the telescope's popularity is simple to explain.

"It allows us to see the universe in a way we don't have to explain. A picture is worth 1,000 words and so we look back in time at some of the earliest galaxies," he said.

"What we deliver back are stunning images of these fairly early galaxies," Mountain said. "And so we can't disassociate science from the image because there's actually great meaning in the science and the public actually engages in that when they look at these great pictures."

Steve Hawley is one of the astronauts who deployed Hubble. He is also an astronomer and thinks he understands why Hubble resonates with so many people.

"The pictures are breathtaking; the science discoveries are mind boggling. I will be sitting next to someone on an airplane and they will ask me what do I do, and I say I work for NASA and they'll say 'oh NASA,' and they think the shuttle goes to the moon and we launch from Houston but they know about Hubble."

What makes people remember Hubble when they aren't ordinarily interested in space? Hawley has wondered about that.

"Whatever it turns out to be we need to learn that lesson because we need to apply it to other things we are doing. If it's the pictures, if it's the drama is, you know you can always pick up the paper and read something new Hubble has done, maybe people think they are getting value for their tax dollars, but as far as I know we never really studied it, or asked someone who knows how to do that kind of thing to study it, and tell us what it really was about Hubble that people found so appealing."

Largest Telescope Would Be Out of this World

By Jeremy Hsu
16 April 2008
A telescope on the far side of the moon could probe the "dark ages" of the universe while blocking out the radio-wavelength noise of Earth civilizations.

Up to one hundred thousand antennas would form the Dark Ages Lunar Interferometer (DALI), the largest telescope ever built, and allow astronomers to hear faint whispering signals from a time when no stars even existed.

"This will look at one of the most fundamental questions ever conceived, back when the universe was made up almost entirely of hydrogen and helium — no stars, no galaxies," said Kurt Weiler, senior astronomer at the U.S. Naval Research Laboratory.

The so-called dark ages of astronomy describe a half-billion year period following the Big Bang when clouds of ionized gas cooled as the universe expanded. The only faint noise came from hydrogen atoms doing spin-flips, which gives off radio-wavelength signals that astronomers can pick up on. Scientists currently estimate that the universe is about 13.7 billion years old.

"What happens is that because of the Big Bang there's a background glow," Weiler noted. "The spin-flip will absorb the glow of the older material and will give us a signature that we can see."

However, the ongoing expansion of the universe has stretched or red-shifted the hydrogen signature from just 21 centimeters to several meters. That means the signals can easily get masked by louder Earth transmissions in the same wavelength, unless astronomers find a quieter listening spot.

"The back side of the moon is the only place in the local universe shielded from manmade transmissions," Weiler told SPACE.com.

The DALI design resembles existing radio telescope arrays in the Netherlands, Australia, and New Mexico. But sending such an array to the moon requires lighter material that can save on launch costs, not to mention survive the harsh lunar conditions.

One candidate is polyimide, a plastic-like film which can act as an antenna when plated with metal. University of Colorado researchers are testing the film's durability by exposing it to harsh ultraviolet rays, as well as the extreme temperatures like that of boiling water and super-cold liquid nitrogen.

The film antennas would be rolled up and then unrolled for deployment across 30 miles (48 km) of lunar surface, arrayed in one thousand stations containing one hundred antennas each. Still, getting the entire load to the moon represents a challenge.

"Even though each antenna may weigh a few ounces, you're talking about needing at least heavy lift vehicles," Weiler noted. "They all add up fast."

The U.S. Naval Research Laboratory is sharing NASA funding with an MIT-based team working on another lunar telescope separate from DALI. Their collaboration may finally realize a dream that many astronomers had even before the first Apollo landings on the moon.

"Probing the dark ages presents the opportunity to watch the young Universe evolve," said Joseph Lazio, NRL astronomer and head of the DALI proposal. "Just as current cosmological studies have both fascinated and surprised us, I anticipate that DALI will lead both to increased understanding of the Universe and unexpected discoveries."

How to Find What You’re Looking For?

If your new telescope has go-to capability, all you need to do is follow the manufacturer’s instructions for initially training the instrument and then use the go-to controller to point your telescope at whatever you wish to view. Bear in mind, of course, that light pollution or other atmospheric conditions may obscure your view. Go-to technology is wonderful, but it can’t work miracles. It will point you in the right direction, but it can’t guarantee that you’ll always see what you’re looking for. If your instrument does not have a go-to controller, glance back at Chapter 1, which introduces the idea of celestial coordinates and altazimuth coordinates as well as the utility of constellations as celestial landmarks. Later chapters have more to say about finding specific objects. What you should familiarize yourself with now, however, is the finderscope affixed to the side of your telescope. Unless you have a rich-field telescope, commanding about a three- or four-degree slice of the sky, you will find it almost impossible to locate with the main telescope anything you happen to see with your naked eye. (“There’s Venus! But why can’t I find it with this #^$%@% telescope!?”) Take the time and effort to follow what your instruction manual says about adjusting the finderscope so that it can be used to locate objects quickly. This adjustment should take just a few minutes and can be done in daylight; once it’s done, it’s done (at least until you or someone else bumps the finder out of alignment). In any case, the alignment process is far less tedious and frustrating than trying to sight with your naked eye along the telescope tube and then just hoping you can finally find what you’re looking for.
Another option is called a Telrad Reflex Sight. Many amateurs use one of these—an inexpensive “bullseye” on the sky. In many ways, this product is even more helpful than a finderscope.

Light Pollution and What to Do About It

Light pollution is the obscuring of celestial objects by artificial light sources.
What do you do about it?
You avoid city lights, if you can. The recent trend toward those peach-colored, highpressure, sodium-vapor and bluish metal-halide streetlights may make some people feel safer, but the lamps have also greatly increased light pollution, even in smaller urban areas.
Here are some ways to reduce the effects of light pollution:

• Rise above the streetlights. Set up your telescope on a hill or a safe roof. The cumulative effect of the streetlights will still blot out many of the less bright objects, especially near the horizon, but at least you won’t be trying to look up through the nearest streetlights.
• Study the sky in a direction away from light sources. If your city’s downtown area is east of your location, look west rather than east.
• Get out of town. Scout out some rural retreats away from the city lights but sufficiently clear of trees to allow reasonably unobstructed viewing. Local state parks are often a good option. It may be best to choose parks that offer overnight camping, since some public parks are open only from dawn to dusk. Don’t trespass!
• If you get very interested in observing, you can purchase filters for your telescope that will block out a good portion of the light pollution caused by streetlights. Such filters are available from Meade Instruments, Orion, and other suppliers. Be aware, however, that these filters are most useful for astrophotography or digital imaging and are less effective if your primary imaging device is your own retina. Also, all filters block light, dimming the image you see; so small-aperture telescopes will suffer most from this side effect.
• Write your local city government and encourage officials to install lowpressure, downward-facing sodium lamps. These lights have a yellowish glow and are highly energy efficient. You can get many good ideas on how to reduce light pollution from the International Dark Sky Association (find more at www. darksky.org/).

Unless you live in a nest of searchlights, there should still be enough for a beginner to see.

How to Become an Astrophotographer?

Once you get hooked on looking through a telescope, sooner or later you’re going to want to start recording what you see. One very enjoyable activity is to make drawings, but many serious amateurs sooner or later turn to photography. Astrophotography can be done with any good single-lens reflex (SLR) camera, the right kind of adapter to mate it with your telescope, and a sturdy tripod and mount with a tracking motor to compensate for the rotation of the earth during the long exposures are usually necessary.

As digital technology has greatly simplified and expanded the possibilities of finding objects in space, it has also simplified and expanded the field of professional as well as amateur astrophotography. We discussed how charge-coupled devices (CCDs) have largely replaced conventional photographic film for most astronomical imaging through major earth-based telescopes as well as such space-based instruments as the Hubble Space Telescope. Just as, in recent years, the cost of go-to technology has been greatly reduced, so now is digital imaging within the reach of serious amateurs. The operative word is “serious.” Meade’s Pictor 1616XTE CCD system costs more than $6,000, but the more “entry-level” Pictor 415XTE comes in at just under $2,000. And a very respectable camera from the Santa Barbara Instrument Group (SBIG) called the SBIG ST7 can be purchased (at the time of this writing) for under $3,000. It is likely that, over the years, the cost of CCD imaging will fall even further.

If you are interested in astrophotography, whether using conventional film or with CCD imaging, check out Michael A. Covington’s excellent Astrophotography for the Amateur (Cambridge University Press, 1999) or Jeffrey R. Charles’s Practical Astrophotography (Springer Verlag, 2000)