Binocular Observing

If you’re like most people, telescopes come to your mind when you hear the word stargazing. There’s a good reason for that. A quality telescope will give you a much brighter and more magnified view of objects in the night sky than any other optical instrument.

Handheld binoculars will never replace telescopes for nighttime viewing, but binoculars do offer several advantages over telescopes. They are much smaller and lighter than any telescope, and they allow you to view the sky with both eyes instead of just one. (Binoviewers allow you to use both eyes with a telescope, so that’s not strictly limited to handheld binoculars.) Also, star fields look rich and crisp with good binoculars due to their unobstructed optics, light-gathering capability, and wide field-of-view.

I always carry my binoculars when I’m out under the stars, even when I’m primarily using a telescope. Over the years, I’ve discovered that even a modest handheld binocular like the Vortex Viper HD 10×42 I use can reveal a wide range of double stars, star clusters, nebulae, and galaxies. Part of the fun of binocular observing is just the challenge of successfully “bagging” deep sky objects that are usually thought of as telescopic targets.

The only requirements for observing these objects are knowing where to look and what to look for, and using a solid rest. For any binocular larger than 10×50, you will probably need a tripod to get a steady view. For smaller binoculars, the easiest way to get a solid rest is to simply lie on your back with your elbows braced. Trust me, you’ll see more and stay far more comfortable observing from that position than you will observing from a standing position.

Knowing what to look for with a binocular mainly involves thinking small. Most binoculars have magnifications of 8 or 10×, while telescopes are often used at magnifications of perhaps 40–200×, and occasionally even more. The September sky contains a wide variety of binocular targets that will give you a good idea of the range of objects that one can observe with a handheld binocular.

Double stars

Binoculars are great for observing wider double stars with fairly bright components. Even wide doubles are pretty tight for binoculars to split, so a solid rest is especially important for viewing these stars. One of the best binocular doubles in the September sky is Albireo, the star at the head of the constellation Cygnus, or the foot of the Northern Cross asterism. This double is famous for its contrasting gold and blue component stars. The colors of the components are more difficult to see with binoculars than with telescopes, but binoculars will neatly split the star into a tight pair of sparkling pinpricks of light. Albireo’s components are separated by 34 arcseconds, the equivalent of a 10-inch (25-cm) separation at a distance of 1 mile (1.6 km).

Star clusters

Open star clusters vary widely in size, brightness, and star density. A few clusters, like the Pleiades, are so large that they look best when viewed with binoculars. More typical open clusters look like round, fuzzy patches of light, perhaps with a few individual stars resolved.

Compared to most open clusters, globular star clusters contain far more stars packed into a smaller area. With binoculars, bright globular clusters look like small evenly illuminated knots of light—almost like fuzzy oversized stars.

Both types of star clusters are scattered liberally across the evening sky in late summer and early autumn. Most open clusters lie along the band of the Milky Way; you should be able to find a few of them just by scanning along the Milky Way with a binocular. Some globular clusters lie along the band of the Milky Way, but they are also scattered across the rest of the sky.

M22 is one of the brightest globular clusters in the September sky. It lies in the constellation Sagittarius, near the thickest part of the Milky Way. M22 lies just northwest of the “bow” of Sagittarius.

Nebulae

Emission nebulae vary widely in shape, size, and brightness. The brightest of these gas clouds are easily visible in binoculars, and careful observation will reveal the general shape and structure of several nebulae. M8, the Lagoon Nebula, is the brightest emission nebula in the evening sky right now. This nebula lies about 7° west-southwest of M22. It is bright enough that you should be able to see it with the unaided eye as a brighter spot in the Milky Way.

Most planetary nebulae are too small to be observable with binoculars, but M27 (the Dumbbell Nebula) and NGC 7293 (the Helix Nebula) are large enough and bright enough that they are fairly easy to observe. The Helix is several times larger than the Dumbbell, but both planetaries are visible as soft round disks of light. See the September 2024 and October 2023 Study Guides for directions on how to find the Dumbbell and Helix, respectively. The Helix Nebula will also be described next month in October 2025. (Or buy the book shown on this page.)

Galaxies

Quite a few large galaxies are bright enough to be visible with binoculars. You certainly won’t be able to see spiral structure within these galaxies, but binoculars will reveal the general shape, size, and brightness of each one. Best of all, you’ll be able to see each galaxy in the context of its surroundings—a huge field of pinprick stars. Telescopes don’t give the same effect even though they can reveal more detail in the galaxies themselves.

September isn’t the greatest time of year for observing galaxies, but there are a few bright specimens that are getting pretty high in the east these evenings. M31, the Andromeda Galaxy, is the best and brightest of these. If you don’t know how to find it, see the December 2023 “Exploring Our Skies” for detailed directions.