Observing

This page is divided into two sections: Observing Ideas and Observing Guides

Observing Ideas

Whether you stargaze with the naked eye, binoculars, or a telescope, there are some simple procedures that will help you get the most out of your vision. These basic tips are geared toward making the most of the faraway stars’ faint light:

Observing the night sky should be something that grows at your own pace. Some people are content to remain naked-eye observers all their lives, never using so much as a pair of binoculars. Others need as much telescope as they can get, sometimes spending tens of thousands of dollars on the base telescope alone.

No matter where they fall in this continuum, visual astronomer are using their eyes as their biological input device. It makes sense then to learn a little bit about making the most of your night vision, and also to address some organizational skills that can help you better enjoy the night sky.


Seek out dark skies. Sadly, areas with pristine dark-sky conditions are disappearing at an alarming rate. Still, some areas are darker than others, and it pays to seek out the absolute darkest skies you can. This will reveal many objects that may have been hidden due to the bright atmospheric veil. Also plan on observing faint objects when the Moon is absent from the sky whenever possible.

Prepare for tonight’s observing during the day. Your night vision may be compromised if you spent part of the preceding day in a high-brightness setting. If you’re planning to observe on a given night, wear sunglasses during the day if appropriate, and avoid tremendously bright areas.

Adjust to the dark, and preserve your dark adaptation. Once you are out under the stars, remember that your most dramatic dark adaptation will take place in the first half hour or so. But remember also that the eye’s sensitivity will continue to improve over the course of an hour or more. Be prepared by using a dim red flashlight to check charts or notes, since dim red light will best preserve your eyes’ dark adaptation. You can convert a regular small flashlight to an astronomical one by fashioning a filter constructed of one or more layers of heavy red construction paper. Or, buy or build one based upon a red light-emitting diode.

Look to the side of faint objects. Because of the way our eyes are constructed, it’s difficult to see faint objects in the central field of vision. Averted vision lets you study the faintest possible detail using your peripheral vision; you can see fainter detail if you don’t look directly at the object. Try looking at a faint object by looking just to its right or left, or just above or below it. You will find that it’s easier than it sounds, and you will end up seeing objects that are otherwise invisible.

Let the image “build” for a few seconds. The retina is also able to “store” light for brief periods. Take advantage of this by letting the image build on your retina for several seconds before you move your eyes or, if applicable, your optical instrument. When using a telescope, try the opposite method, too: “jiggling” the instrument can sometimes reveal hidden detail.

Dress as if it were 20 degrees colder. Since skywatching requires little activity, it’ll always seem a bit colder than the thermometer indicates. It makes sense to don extra layers of clothing, even in summertime, for you’ll see much more if you’re comfortable.

Use any available instrument. Even simple binoculars will reveal many of the sky’s fascinating secrets! Surprisingly, many inexpensive telescopes provide breathtaking views of the Moon and other bright objects. You may even wish to invest in a larger instrument later on!

Plan your observing session. It’s quite sensible to plan your observing ahead of time. Assemble your charts and notes ahead of time, and develop of plan of action — even if you only plan to locate a single sky object. Of course, if and when your observing regimen becomes more complex, good planning is even more important!

Log your observations. It’s a good idea to create some means by which you can document your observing. Not only will this provide a permanent record of your activities, but it will also result in higher quality observing. For example, the more detail you sketch, the more detail you will see while doing so.


There is quite a lot that you can do to foster more rewarding observing, techniques that will become second nature anytime you venture out under The Sky Tonight^®.

Observing Guides

It’s difficult to locate many constellations until you’ve spent some time under the stars. Star charts, maps, and atlases are great for identifying the constellations, but they must be used in conjunction with actual observing.

The best guides are easy to use. Some recommendations follow, but there are many useful guides not listed that you might find ideal for your purposes.

Planispheres

These are my favorite star maps for naked-eye and binocular observing. On a planisphere, a circular map of the entire visible heavens is typically mounted inside a housing, which masks stars that are below the horizon at a given date and time.

Since the sky appears as the inside of a great sphere (the “celestial sphere”), distortion occurs when that sphere is mapped onto a flat surface. Some planispheres reduce the distortion by splitting the sky in half, while others stretch southerly constellations in an east-west direction. Planispheres, however, are not difficult to use; one quickly becomes accustomed to the inherent distortion.

Planispheres are designed for specific latitudes. Central Illinois observers should select a planisphere designed for observers at 40 degrees north latitude.

A tremendous planisphere is David H. Levy’s Guide to the Stars, available through Sky Publishing Corporation and other mail order sources. This planisphere is huge, measuring sixteen inches in diameter, and is extremely rugged, being constructed of heavy, flexible plastic. The stars are black on a white background, making this planisphere very readable with a red observer’s light.

The “classic” planisphere is Edmund Scientific’s Star and Planet Locator. Edmund’s 8.5" square device is made of cardboard, but is nonetheless fairly rugged. The big advantages of Edmund Scientific’s device are its relatively low cost, white-on-blue map, and ease of use.

David Chandler’s The Night Sky planisphere reduces distortion by splitting the sky into two maps. The two-sided planisphere succeeds in reducing distortion, and it’s easy to use once you get accustomed to it. This planisphere is available in two sizes; go for the large one unless you want a second one for the car’s glove compartment. Another advantage to this planisphere is that — since it splits the sky over two halves — it can show as much sky area as a conventional planisphere, while being significantly smaller.

The most beautiful planisphere I own is The Miller Planisphere, sold by a variety of online resellers. Its black and gold outer ring is visually stunning, and its dark blue sky with gold lettering and white stars makes for easy reading inside, although it’s a little harder to read under the stars with a red light. I prefer the 10.5" model, but the 5.5" model is surpisingly readable for its size.

An excellent planisphere — that now appears to be out-of-print — was David Kennedal’s Precision Planet and Star Locator, which you should consider if you can locate one. The Locator is constructed of heavy, flexible plastic, making it extremely rugged and virtually immune to damage. Black stars on a white background make this planisphere easy to read by a red observer’s light.

Star Maps

Star maps come in all shapes and sizes — and for all budgets! Bear in mind that the most expensive star map is not necessarily the best for the beginning observer. Indeed, most of the expensive star maps are not designed for the casual observer.

An excellent introductory book is simply entitled The Stars, by the late H.A. Rey. It’s subtitled “A New Way to See Them,” and really does make learning the constellations easy and enjoyable. The Stars is available online and through many bookstores.

Magazines

Magazines are excellent investments. Many come with a monthly star chart, and all contain useful sky information.

Sky & Telescope magazine is one of the best publications for the amateur astronomer. Material ranges from introductory level to advanced. Sky & Telescope features a wealth of photographs, charts, and maps. The text is written in a straightforward, easy-to-read manner. Available from Sky Publishing Corporation.

Astronomy magazine is considered by many to be an excellent introductory publication. Astronomy features lots of artwork, and much of the text is written in an informal, enthusiastic style. Available from Kalmbach Publishing Company.

Computer Resources

Computer users may wish to purchase one of the many excellent software packages that are available for amateur astronomers. Astronomy software is usually quite accurate, and — if all you want is a program that simulates the visibility of the constellations — almost any commercial product will do. There are also several shareware programs available, and these vary widely in terms of speed and accuracy.

I use Starry Night Pro on a Macintosh computer to plan and write The Sky Tonight^®.

Several of the commercial programs take advantage of today’s tremendous storage capacity, offering databases of millions of stars and sky objects. Try a program before purchasing if at all possible, since — among other issues — some applications may require more computing horsepower than others. Interestingly, some of the larger programs with immense databases outperform some compact programs with small star catalogs.

Sky & Telescope magazine’s web site is a tremendous resource, and it can lead you to many others. It’s at http://skyandtelescope.com/.

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