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How to make the most of
your observation session

Suit up for Winter Observing
A few simple measures let you venture out under the winter stars in complete comfort no matter what the temperature.
by John Shibley


 

Outside a frosted window, the winter Milky Way cascades overhead with its icy-bright stars, glistening open clusters, and splashy, glowing gas clouds. Inside, where summer still prevails, you recline on the couch, television remote in hand, muttering If only it were warmer outside. Not far away, a trusty telescope or pair of binoculars lies hibernating in a snug closet like a slumbering bear. The furnace's reassuring sound kicks in, but it hardly offsets the periodic pangs of guilt you feel. Another gloriously clear night wasted.

Indeed, winter reduces even the most avid skywatchers to wintertime door-stoop astronomers who glance quickly at a crescent Moon or an occasional grouping of planets. But it doesn't have to be that way. A moderate amount of effort and cold-weather savvy can eliminate what stands between you specifically the cold weather and an enjoyable evening under winter's brilliant skies.

Think Layers
First of all, dump the guilt. Eons of evolution have dictated that almost all living creatures should consider warmth a good thing. Accordingly, your instincts every fiber in your being say to forget star clusters until spring. But here's where it pays to be a sentient being. You know how to take the warmth with you under the stars. The source: your body; the means: layers of trapped air.

That's what the army concluded after spending (it's rumored) millions of dollars on how to dress for cold weather. It's not necessarily the material that traps heat, but layers of still air. Hence the secret to winter warmth is to insulate with air. Dead air forms a buffer between your heat-releasing skin and the cold, clear night that seeks to suck every joule of infrared energy out of your body.

The best way to accumulate dead air is to create pockets of it. Dress in several layers to create at least three inches of insulation (again, the army study) between you and the night. And make sure these layers are loose, so blood circulation won't get cut off.

Torso and Brain First
Pay particular attention to your body's torso. That's where most of the vital organs reside. An evolutionary trip-wire shunts blood away from your extremities (like fingers and toes, followed by arms and legs) toward the torso's organs if it senses things are getting too nippy.

Cover it with a T-shirt, then layer on a turtleneck, a heavy wool sweater (that alone has thousands of air pockets), topped by a winter jacket with fiber-fill insulation.

Aside from protecting what's inside the torso, this autonomic reflex kicks in for another vital organ. If the brain's heat loss becomes extreme, blood vessels in the toes and fingers constrict so the brain gets more blood. In extreme instances, this reflex will even sacrifice limbs to the ravages of frostbite.

Long before that happens, though, your toes and fingers will feel cold and clammy. So the secret to keeping your extremities warm lies in literally keeping a lid on heat loss through the head. Keep it covered, which means the top, cheeks, ears . . . whatever can hand off heat. This is where a balaclava comes in handy. If your winter jacket has a hood, all the better.

They Aren't Expendable
But let's not assess the brain and other internal organs complete blame if your fingers and toes get uncomfortable. Your digits themselves surrender heat. Again, the secret to keeping them warm lies in layers.

For the fingers, start with cotton (which draws perspiration away from the skin) glove liners topped by wool mittens. Such liners assure a certain measure of dexterity if you must doff the mitts to insert an eyepiece into the telescope.

You won't need such flexibility when it comes to your feet, unless you insert eyepieces in unorthodox ways. Slip feet into light cotton socks covered by wool socks, all inside oversized snowmobile boots lined with felt. Some grizzled winter observers advise going with a boot one size larger to accommodate still more layers of socks. Again, don't pack things too tightly; many a skywatcher has suffered clammy feet brought on by a lack of blood circulation.

Finally, one big area of real estate lies between feet and torso. Cover your legs in long underwear, heavy wool pants, and a thin nylon wind shell for durability when kneeling on the ground. A waterproof wind shell might be useful, in case it's damp and cold.

Embrace Low-Tech
One word from the wise: Be wary of high-tech garments that promise warmth at any temperature. So-called winter activity wear assumes you'll be doing a fair amount of heavy activity like skiing or snowshoeing. In reality, observing entails long periods of inactivity, save for the occasional elevated heartbeat when the Orion Nebula drifts through an eyepiece's field of view. For the observer's purpose, cotton to absorb perspiration and wool to trap body heat does just fine.

With this air of simplicity in mind, suit up like a medieval knight and awake your slumbering scope for a ride under the stars. Wrapped in layers of wool and cotton, you'll be protected within a climatic cocoon of spring-like temperatures. Enjoy yourself, for in a few months summer returns with a vengeance to quash that primal urge to stay close to heating vents.


Meteor Watching 101: Tips and terms
By Robert Roy Britt
Senior Science Writer
posted: 30 June 2005
07:58 am

Meteor Watching Tips

> The part of Earth where dawn is breaking is always at the leading edge of our planet's plunge along its orbital path around the Sun. This part of the planet tends to "catch" oncoming meteors left by a comet, whereas the other side of Earth, where it is dusk or late evening, outruns the debris. For that reason, the hours between midnight and dawn are typically the best time to watch a meteor shower.

> Allow time for your eyes to adjust to darkness. A good hour is smart, so that you can also practice some prior to prime observing time.

> Dress warmer than you think you need to, especially in winter.

> Bring a lounge chair or blanket, so you can relax and look up with ease.

> During meteor showers, shooting stars appear to emanate from a point in the sky called the radiant. There are different ideas about how to use this fact to aid in spotting meteors. Robert Lunsford has these thoughts:

One idea is that it is preferable to look away from the radiant so that the shower meteors you see will be longer and therefore easy to detect motion. As Mark Davis stated one should look 20-40 degrees distant. At this distance the radiant is still in your field of view so that shower association is still fairly easy.

Those who look directly at the radiant can see shower activity travel in any direction. Shower association will be fairly obvious. Meteors that appear near the radiant will be foreshortened and therefore the motion will be more difficult to detect.

I would suggest that new observers face slightly away from the radiant. Those who enjoy good perception over a large field of view may be able to directly face the radiant with no problems. Those who prefer to face the radiant must not do so unless the radiant is at least 50 degrees high in the sky. If you don't then you are wasting the bottom portion of your field of view on the ground!




Full coverage: Leonids Special Report

Glossary of meteor terms

SOURCE FOR GLOSSARY:
International Meteor Organization

Fireball: A bright meteor with an apparent visual magnitude of -4 mag. or brighter.

Limiting Magnitude: Generally denotes the faintest star visible during an observation and evaluates the quality of the sky as well as the observing technique. The magnitude of the faintest meteor visible can be different from the stellar limiting magnitude, particularly for photographic and video observations. Visual observations assume about the same limiting magnitudes for stars and meteors.

Magnitude: The brightness of stars and other celestial objects. Smaller numbers are brighter (negative numbers are the brightest). The scale assumes dark skies. Venus is -4.4, and the faintest star visible to the naked eye is about +6.0.

Meteor: The light phenomenon which results from the entry into the Earth's atmosphere of a solid particle from space.

Meteorite: A natural object of extraterrestrial origin (meteoroid) that survives passage through the atmosphere and hits the ground.

Meteoroid: A solid object moving in interplanetary space, of a size considerably smaller than a asteroid and considerably larger than an atom or molecule.

Meteoroid Stream: Stream of solid particles released from a parent body such as a comet or asteroid, moving on similar orbits. Various ejection directions and velocities for individual meteoroids cause the width of a stream and the gradual distribution of meteoroids over the entire average orbit.

Meteor Shower: A number of meteors with approximately parallel trajectories. The meteors belonging to one shower appear to emanate from their radiant.

Micrometeorite: A small extraterrestrial particle that has survived entry into the Earth's atmosphere. The actual size is not rigorously constrained but is operationally defined by the collection procedure. Micrometeorites found on the Earth's surface are smaller than 1mm, those collected in the Stratosphere are rarely as large as 50 micro-m.

Radiant: The point in the sky where meteors from a specific shower seem to come from. (Technically: The point where the backward projection of the meteor trajectory intersects the celestial sphere.)

Sporadic Meteors: Those not associated with a particular meteor shower.

UT, or Universal Time, is 5 hours ahead of Eastern Standard Time, and 4 hours ahead of the East Coast during Daylight Savings Time. UT is the same as Greenwich Mean Time (GMT), the 0 hour beginning at Greenwich mean midnight.

Zenith: The point in celestial sphere directly overhead from an observer.

ZHR (Zenith Hourly Rate): The number of shower meteors per hour one observer would see if his limiting magnitude is 6.5 magnitude and the radiant is in his zenith.

SOURCE FOR GLOSSARY: International Meteor Organization