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111 Deep-Sky Wonders for Light-Polluted Skies

by James Mullaney

Andromeda Galaxy
The Andromeda Galaxy (Messier 31) is visible in binoculars, even from within a city.
S&T: Richard Tresch Fienberg
Where I live, 30 miles west of downtown Philadelphia (near historic Valley Forge, Pennsylvania), the glow of the nighttime sky is often bright enough that I can read my star charts without the aid of a red flashlight. Sadly, for most of the stargazing community in our country, this is a pretty typical situation. Yet despite such blatant intrusions on the once sacred darkness of the night sky, many deep-sky wonders can still be seen and enjoyed in a small telescope. In fact, some keen-eyed observers have even been able to glimpse the brightest quasar, 13th-magnitude 3C 273 in Virgo. Considering that the object is at a distance of around 2 billion light-years, it is amazing that it can be seen at all under such conditions, let alone with apertures as small as 5 or 6 inches!

Orion Nebula
The Orion Nebula (Messier 42) is the brightest emission nebula visible from midnorthern latitudes.
S&T: Richard Tresch Fienberg
Presented here is a table of 111 deep-sky showpieces scattered around the heavens, most of them visible from midnorthern latitudes through even the brightest of skies. Since stars have the highest per-unit-area brightness, double and multiple stars and bright star clusters dominate the selection. Nebulae and galaxies are still well represented even though these faint fuzzies suffer the most from light pollution. You can readily find all of them within their respective constellations using a good star atlas such as Sky Atlas 2000.0, and the vast majority are plotted in more basic atlases and on detailed star maps. In fact, many of these targets appear on Sky & Telescope's monthly centerfold star map.

A few observing hints are in order. While low magnifications and wide fields of view are typically used for finding deep-sky objects, higher magnification has the benefit of darkening the background sky — something to keep in mind when you're looking through light pollution. Close doubles and tight clusters (especially globulars) are best seen on nights of steady seeing, while nebulae and galaxies should be saved for nights when transparency is excellent. All deep-sky objects are at their best when on or near the meridian and, therefore, highest in the sky.

Pleiades
The Pleiades (Messier 45) in Taurus is a fine example of an open star cluster.
S&T: Richard Tresch Fienberg
Use direct vision where color perception and resolution are important, and averted vision (looking slightly to one side of the object) for seeing faint details. In the latter case, a dark opaque cloth covering your head down to your shoulders will help prevent unwanted light from streetlights, passing cars, and the glowing sky itself from ruining your dark adaptation. And finally, as a rule, the later at night you observe, the less light pollution you will have to contend with as businesses close, neighbors go to bed, and the busy world around you shuts down for the night.

The table appears on the next three pages. For more information about its contents, see the original version of this article, which appeared in the April 2003 Sky & Telescope. If you don't have that issue handy, the article is also available in the S&T Magazine Archive as a 901-kilobyte PDF. The PDF can be downloaded for free by archive subscribers and costs $2.95 otherwise. To read the PDF, you'll need Adobe Reader, which is available at no cost for most computers.



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