Friday, June 6, 2008

Binocular Astronomy

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One of the best things a budding astronomer can do is not buy a telescope!

Instead, buy two!! Quite simply, a good set of binoculars is a better way to start off. For more information on why this is true, see "Your first telescope".

Update: There is a caveat I should mention, handheld binoculars will be unlikely to give you a good view of Saturn's rings. I'll write more about beginner telecsopes before Christmas.

Choosing Binoculars

If you are looking for binoculars that you can use to look at the stars, I recommend you read Binoculars for Astronomy over at The Universe Today. Tammy Plotner, a professional astronomer and frequent writer on binocular astronomy, covers size, weight, portability, magnification, size of the objective lens (large end), and exit pupil (small end), tripod adapters, and what types are suited to children versus adults.

Because they are so versatile, many astronomers have several pairs. For example, I have have a compact 8x21, mid-size 10x50, and a large 11x70. The first pair doesn't really gather enough light but makes up for it in portability. The last pair is near the limit of being hand holdable. Anything larger are considered giants.

Giant binoculars require tripods (some have seats) and are used by comet hunters amongst others. They come in sizes like 15x80, 25x100, 30x90, 25x125.

Some astronomers so enjoy using both eyes they get binocular eyepiece mounts for normal telescopes.

One of the most advanced telescopes in the world, called the large binocular telescope uses two scopes with 8.4 meter diameter mirrors!

Things to see with binoculars

Below I've summarized some of Tammy's articles and given viewing dates assuming evening viewing around 9pm.
  • Get Sirius! (March 2008) - describes how to use Sirius to find the open clusters M41, M47, and M50 [January-April]. I wrote on this article before, here.
  • What to Look at With Binoculars - describes how to find the open clusters M44 (The Beehive), and M67 [December-June]; the globular cluster M3 [June-September]; the open cluster Melotte 111 [February-August]; the galaxies M65, M66, NGC 3628 [February-July]; and M105, and M96 [June-July].
Tammy has a series of articles called "What's Up" at the Universe Today as well she has written a book " The Night Sky Companion 2008-2009". The What's Up articles cover what can be seen with binoculars, scopes, and the naked eye on specific dates and may require staying up late or rising early. Many of these take into account the brightness of the moon, as well as the position of planets and asteroids that will vary from year to year.


I forgot to include a few objects on my list:
  • M45 (Seven Sisters), the famous open cluster in Taurus [October-April]
  • M42 and M43, in the sword of Orion Nebula [November-April]
  • The Double-Double, a multiple star, in Lyra [May-December]
  • Alberio, a multi-coloured double star in Cygnus [May-December]
Also, the May/June 2008 issue of "Sky News Canada" has an article titled "Welcome To The Binocular Universe" ... "These double-barrelled optical wonders will enhance your exploration of the night sky." written by Gary Seronik.

Update: David Hofland of the North-East Alabama Astronomical League sent me a copy of his NEAAL article describing how to make a liquid filled stabilizer for binoculars using PVC, contact cement, and bungees. Granted it looks a bit odd, but it should have some advantages over a camera tripod when looking way up. I've reprinted it here with permission.


I'd love to hear from anyone with ideas about good targets for hand held binoculars. I'd also like to hear from people with binocular experience south of the equator. Please comment or respond via the guestbook or email form on the sidebar. Thanks.

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