Binocular Astronomy

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.

Update:

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.

Feedback

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.

What's your favorite asterism?

So what's an asterism?

When we look at the night sky we see stars and groups of stars. Some of these groups are among the 88 official constellations. Like Orion, Hercules, Ursa Major, etc. For a list of the official constellations look here). But some of the best known star groups aren't actually constellations! Some are even better known than the official constellations. These unofficial groups are called asterisms. And some of these are better known than the official constellations.

Teaching the sky

Cubs learning the sky for their Astronomer badge will learn some asterisms as a way to identify the 5 constellations they need. Listed below are a few of the most common I teach to our cubs. I've listed them by by season assuming you'll be looking just after twilight.

All year (circumpolar):

• The Big Dipper (Ursa Major) as well as the Little Dipper (Ursa Minor)
• The Pointers (Ursa Major)

Summer:

• The Summer Triangle (Cygnus, Lyra, Aquila): June-November
  
• The Keystone (Hercules): April-September
• The Teapot (Sagittarius): July-September
• The Sickle (Leo): July-January
  

Winter:

• Orion's Belt and Orion's Sword (Orion): November-April
  
• The Kids (Auriga): September-May
  

More asterisms

There are also binocular and telescopic asterisms. One of the most famous and striking is called the Coat hanger (Brocchi's Cluster). The Coat hanger can be spotted by eye but needs binoculars to see its pattern. It can be found not far from the western edge of the Summer Triangle moving from Vega in Lyra to Altair in Aquila just past Alberio.

In addition to the Wikipedia article, there are a many sites with lists of asterisms.

• SEDS (Students for the Exploration and Development of Space) has a list here.
• Sofware Bisque (The Sky) have a good list of binocular and scope asterisms here.

So, what's your favorite asterism?

I wanted to write an article on asterims for Cubs, Scouts and beginners and had expected to find longer online lists of asterisms than were at Wikipedia and SEDS. I also have very little information on southern hemisphere asterisms.

Do you know any that aren't on these lists? Do you have a favorite?

Please let me know via comment or email.

David Dunlap Observatory Tour and Photos

On March 4th 2008, the 433rd Cubs, parents, and a few Scouts paid a visit to the David Dunlap Observatory. Unfortunately the weather did not cooperate and we couldn't actually see the stars or do our work for the Globe at Night's light pollution awareness project. We were fortunate to beat a major snowstorm that descended on the city shortly after we left.

We were able to take in a presentation at the administration building that covered many of the requirements of the Astronomers Badge. The tour also counts towards requirement B3 or the Black Star. Our cubs had some good questions and demonstrated their knowledge of astronomy including one or two things that surprised me.

Afterward we were able to visit the observatory dome and see the telescope. The scope is quite massive and the Cubs were impressed that it was so finely balanced that impatient astronomers could move the 25 ton assembly by hand!

We learned a bit of the history of the facility, its use for astrophotography, and a renown Canadian astronomer Helen Sawyer Hogg who conducted research at the DDO for many decades.

We also saw a spectrographic lens and learned a bit about some of the work being done, including a study of rather bizarre systems known as contact binaries. In these systems two rapidly co-orbiting stars are so close they actually touch but do not merge! There are a number of interesting question that aren't known about these including how they came so close.

Hopefully, we will be able to return later this spring to actually look through the eyepiece!

Our thanks to Tuba Koktay, Ian Shelton, and Thomas Karmo at the DDO.

Astronomers Badge

Image courtesy of NASA, the Comet is a bonus, click on image for more info
(Credit: Alessandro Dimai at the Col Druscie Observatory)

The 433rd has been working on the astronomer badge. The (paraphrased) requirements include:

1. Showing how to use the pointer stars (Merak and Dubhe) of the Big Dipper to find the Polaris (the North Star - the comet in the photo shows the way).
2. Using a star chart and finding 5 constellations, see Planispheres.
   
3. Learning and relating star lore (classical or aboriginal), see the Wolf Moon for one example.
   
4. Knowing and describing 3 (astronomical) features of the sky, such as comets, asteroids, planetary rings, strange quasi-moons, or other news.
   
5. Knowing about the phases of the moon and tides, see the Tides Game.

Earning an astronomer badge automatically counts for Black Star requirement A11 (finding the north star and 3 constellations).

Requirement 1 is paramount as it can be used to find direction!

Some easy constellations to find (in the northern hemisphere) include:

• Circumpolar (stars that are always up - click the link for a nice animation)


• Ursa Major (the big dipper)
• Ursa Minor (the little dipper)
• Cassiopeia

• Winter Group (look due south around 8pm Feb 10th)


• Orion
• Auriga
  
• Gemini
• Canis Major

• Summer Group


• Cygnus
• Lyra
• Aquila
  
• Hercules
• Scorpius

I would be interested in hearing from Cubs outside of Canada about astronomy requirements in their badges and awards. In particular, I would love to hear from Scouters in the southern hemisphere.

Update: Above I noted that Cubs can double dip on requirements for the Black Star. It turns out they can actually triple dip as the Winter Cubbing badge has a requirement to find the North Star and three night sjy objects!

Update: If you are a Cub leader outside if Canada, please also read The Great Astronomers Badge Swap.  And please click on the BadgeSwap label below to see other related badges and entries.

Build your own Planisphere (Star Finder)!

One of the Astronomer badge requirements is to use a seasonal star chart. One of the most compact and useful star charts is called a Planisphere, Star Finder, or Star Wheel.

Tonight we will send home star finders with our Cubs. Our planisphere came from the National Research Council of Canada web site as a downloadable template you can make yourself, here. For best results print the template on stiff card stock.

The NRC also an online star chart and information on constellations and other astronomy, here. In fact, you could get most of what you need to earn your Astronomers badge from this site alone.

Using a planisphere is simplicity itself, you just dial the disk until the time of day lines up with the current date. Hold it above your head as you look to the sky (otherwise east and west are reversed).

You should adjust for Daylight Savings Time, by subtracting one hour when it is in effect. You don't need to adjust for leap years as the day to day change in the position of the stars is much less than an hour of the Earth's rotation.

Planispheres are actually designed for observers at specific distances from the equator (latitudes). A planisphere disk for Canada and the US, doesn't work well above the Arctic circle or close to the equator. Entirely different planisphere frames and disks are required in the southern hemisphere as the directions reverse.

Some other star finders templates:

• The State of New Jersey publishes one, here. It's not too much different than the NRC one.
• The Royal Astronomical Society of Canada has one, here. And other resources, here.
  
• A southern hemisphere template can be found, here.
• A northern and southern hemisphere templates can be found, here.
• A Lakota star chart that may be usable in a planisphere frame can be found, here, with more information, here.
  

High quality planispheres can be purchased from local astronomy stores or online. One innovative design reduces edge distortion using a two sided approach, here.