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Star Light, Star Bright  (33-5)   By Craig Ritchie

One of the delights of RV camping is enjoying quiet evenings under the stars. But have you ever wondered just what you were looking at? You've driven for several hours and finally arrived at your chosen campsite for the night. It's great - no phones, no emails, no distractions whatsoever. So you sit outside enjoying the evening, perhaps with a glass of wine in hand, and gaze up at the stars. Away from the glaring city lights, it's truly remarkable just how many there are to see. One particularly bright star off to the right catches your eye. Is it the North Star? Or is it the planet Venus? Or is it a distant galaxy blowing to bits in a massive nuclear explosion? With such amazing views outside on every clear night, it's little wonder that many RVers develop an interest in astronomy. If you travel with kids in tow, it's only a matter of time until they start asking about the stars, whether the moon really is made of cheese, or if there are little green people living on Mars. What better way to introduce children to science than by letting them explore the sky above? Astronomy is one of those things that can be as simple or as complex as you care to make it. You can enjoy stargazing with just the naked eye, or dive right in and seek out specific stars and constellations with a high-powered telescope. It's all up to you. The best way to begin exploring the solar system is with a star chart, which is available at any good telescope store. Consider it a map of the sky. Being able to look up and say, "There's the North Star!" or "That's Saturn!" will provide anyone with a sense of satisfaction -- and a sense of your place in the cosmos -- that sticks with you for life. Beginning with a star chart and your naked eye makes a lot of sense, especially if your RV has limited storage space. There's plenty to take in, providing you know where to look. That's where your chart comes in. The average person with average vision can clearly see a galaxy two-an-a-half million light-years away with just the naked eye. Is that cool or what? Learning the night sky with a star chart takes time, but brings hours of entertainment all on its own. Besides, those skills will pay big dividends should you become hooked on stargazing and wind up buying a serious telescope. How do you learn the night sky? Just look up and let curiosity take over. Identify things that grab your attention by comparing them against your star chart. Before long, you'll learn some different constellations or perhaps a planet or two, and find you're having a ball. (Page Top) That Long Distance Feeling Chances are you’ll soon reach a point where you want to look at things in greater detail, and begin thinking about buying a telescope. However, you might want to hold off and go with a good pair of binoculars instead. Most experienced astronomers keep a pair of binoculars close by at all times, for quick peeks or for scanning the sky before using their telescopes to zoom in close. Binoculars come in a range of sizes, the most common being 7x35 or 7x50. The first number refers to the magnification –7x35 binoculars magnify the image by a factor of seven. The second number – the 35 – refers to the diameter of the objective lenses, measured in millimeters. A 7x35 binocular offers the same magnification as a 7x50 model, but the 7x50 has larger lenses, so it lets in more light and is a better choice for looking at the stars. Binoculars offer a number of advantages over telescopes, particularly to RVers who may have to cope with tight storage issues. Apart from being less expensive to buy, binoculars show you a wider view of the sky, so it is much easier to find things when you’re first getting your feet wet. They also give you a view that's right side up and straight in front of you, making it easy to see where you're pointing. Binoculars are also versatile – you can use them to watch birds, wildlife or anything else, so you get much more everyday use out of them. And their performance is surprisingly respectable. Ordinary 7- to 10-power binoculars improve on the naked eye about as much as a good telescope improves on binoculars. You can use them to identify our moon's craters, the ever-changing positions of Jupiter's moons, and the crescent phases of Venus. They'll reveal most of the 109 star clusters, galaxies and nebulae cataloged by 18th-century astronomer Charles Messier – the so-called M List you’ll run across in astronomy books and magazines. Moreover, the skills you'll develop using binoculars are exactly the skills you'll need to put a telescope to good use should you one day decide to invest in one. So when you feel the desire to get more up close and personal with our solar system, start with a good pair of binoculars. If you find you’ve been bitten hard by the astronomy bug, then you can go all out and invest in a telescope. How to Buy a Telescope The vast majority of telescopes are bought during the holiday season and given as gifts, mainly to children. Regrettably, the poor performance of these inexpensive telescopes often discourages the recipients from pursuing their interest in astronomy. It’s hard to become excited when you can’t focus on anything you look at. Many people believe that magnification, or power, is the most important feature of a telescope. That’s a mistake. Makers of poor quality telescopes take advantage of this by claiming their telescopes provide absurdly high magnification, such as "525x" or "675x.” It sounds great, but this is a sure sign of a lousy product. Actually, the main purpose of a telescope is not to magnify, but to gather light. The more light you can gather, the more you will see. As with binoculars, the light-gathering ability of a telescope is determined by the diameter of the scope's main lens. Once you have gathered the light, then you can adjust the magnification of a telescope by using different eyepieces, much like changing lenses on a camera. Most stargazing is done at relatively moderate magnifications of 50x to 150x. Once you go much beyond that, vibration from the slightest source will make it almost impossible to focus on anything. The best place to buy a telescope is from a store that specializes in astronomy. You’ll not only find better quality merchandise at these specialty stores, but great advice as well. Dealers are generally quite willing to explain things and recommend a scope that is right for your particular use. (Page Top) Modern amateur telescopes can be divided into three basic types. Refractor telescopes – the long, tube-shaped ones most of us picture when we think “telescope” – gather light with a large objective lens at one end and focus with an eyepiece at the other. Because there are no obstructions in the path of the light, refractors offer excellent image quality. Newtonian reflector telescopes, invented by Sir Isaac Newton, use mirrors in a shorter, thicker tube with the eyepiece located up front. This design is much more compact and, because the eyepiece is nearly always at a convenient height, they’re considered the most comfortable telescopes to use. Their principal disadvantage is that the dual-mirror design results in lower contrast images than you would see with a refractor model. The Schmidt-Cassegrain style of telescope uses a combination of mirrors and lenses to fold the optical path back onto itself. They are even more compact than Newtonian reflector scopes, and can be totally computer driven. Most serious astronomers wind up with this type as their primary instrument. Selecting a telescope is a matter of making acceptable trade-offs, based on how much you will use it, how much storage space you have available in the RV, and how much you want to spend on your new hobby. There’s no point buying a pricey, computer-controlled, behemoth scope only to find you never use it because it’s such a pain in the neck to set up. A simpler, less expensive telescope that actually gets taken out and used is a far better investment. Astronomy is a lot of fun. Because our RVs take us away from the glaring city lights, campers have the best opportunity to really enjoy this fascinating pastime. Next time you’re hanging out under the stars, gather the kids, take a look up in the sky and see what catches your eye. You may find you’ve discovered a great new hobby that brings a lifetime of pleasure. Points to Remember • Good binoculars are always a better choice than a low quality telescope, and are still useful should you buy a good one. • Avoid cheap department store and toy store telescopes, which tend to be low in quality. • The primary purpose of a telescope is to gather light. So look for a scope that’s large enough in diameter to offer bright images, yet compact enough to fit its storage space in your RV. If the telescope is too large or too much of a pain to set up, you won’t use it, regardless of image quality. What You Can Expect to See Here’s what you can see with a typical six-inch reflector telescope under reasonably clear skies: • All of the planets except Pluto. Saturn's rings are easy to spot, as is the planet Jupiter. Detail on Mars is a bit harder to pick out, but possible on a clear night. Venus, Mercury, Neptune and Uranus are pretty much featureless balls. • Hundreds of named craters and mountain ranges on our moon. • Sunspots and other activity on the sun, if you have a proper filter. But unless you really want to incinerate your eyeballs, do not look at the sun without proper filtration! • All 109 Messier objects, which include nebulae, open and globular clusters, and extended galaxies. Most of these will seem impossibly dim to you at first. Once you become comfortable looking at the night sky, they will seem terribly bright. • Hundreds of other various objects, from meteors to comets. (Page Top) An Astronomy Glossary Aperture The diameter of the primary lens of an astronomical instrument, usually expressed in inches or millimeters. Aphelion The point where an object orbiting the sun is at its greatest distance. Astronomical Unit Approximately equal to the distance between the earth and the sun – about 150,000,000 km or 93,000,000 miles. Black Hole A region of space surrounding a massive collapsed star, from which not even light can escape. Bolide A brilliant meteor, which may explode during its descent through the earth's atmosphere. Celestial Sphere An imaginary sphere surrounding the earth, concentric with the earth's center. Declination One element of the astronomical coordinate system on the sky that is used by astronomers. Declination, which can be thought of as latitude on the earth projected onto the sky, is usually denoted by the lower-case Greek letter delta and is measured north (+) and south (-) of the celestial equator in degrees, minutes, and seconds of arc. Diurnal motion The apparent daily rotation of the sky from east to west. It is due to the real rotation of the earth from west to east. Ecosphere The region around the sun in which the temperatures are neither too hot nor too cold for life to exist. Venus lies near the inner edge of the Ecosphere; Mars is near the outer edge. Equator, celestial The projection of the earth's equator on to the celestial sphere. It divides the sky into two equal hemispheres. Equatorial mount A telescope mounting in which the instrument is set upon an axis which is parallel to the axis of the earth. Faculae Bright, temporary patches on the surface of the sun, usually associated with sunspots. Light Pollution The emission of stray light or glare from street lights, buildings, cities and other man-made objects. Light Year The distance traveled by light in one year, which is approximately 9,460,000,000,000 km. Orbit The path of an artificial or natural celestial body. Satellite A secondary body moving round a planet. Solar System The system made up of the sun, the planets, satellites, comets, asteroids, meteoroids, and interplanetary dust and gas. Spectroscope An instrument used to analyze the light from a star or other luminous object. Sunspots Darker patches on the sun. Their temperature is estimated to be as much as 2,000 degrees Celsius less than that of the area around them, so they appear darker by comparison. Universal Time A measure of time used by astronomers. UT conforms to the daily motion of the sun. Zenith The point directly overhead in the sky. (Page Top)