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Skywatching

Picking the right binoculars and telescopes for astronomers

Presents for astronomers

Every year the range of potential presents for the family astronomer gets bigger and bigger, which makes choices more and more difficult.

There is gear out there for every type and level of amateur astronomer. My suggestion is that if you are an established amateur astronomer, leave "useful lists" lying around to help the rest of the family give you a happy Christmas.

The biggest challenge is to help the budding astronomer find enjoyment in their new activity rather than being discouraged and put off by telescopes that are too complicated, take ages to set up or take down, or are simply useless.

One thing that is always true is that if he or she does not have a good pair of binoculars then consider putting a pair in the stocking, whether or not the recipient is a beginner.

Binoculars are basically a pair of telescopes fastened together. They provide a bit of useful magnification, but their main purpose for astronomy purposes is to collect more light, making faint things visible. The light is collected and images formed by the objective lenses. These are the ones at the end you don't look into.

The images are in turn magnified and made viewable by the eyepiece lenses. In principle, the bigger the objective lenses the better, because they will collect more light. However, this makes the binoculars heavier, harder to hold still, or to use for any length of time.

A good compromise is a pair of 7x50 binoculars—a magnification of seven times and objective lenses 50 mm in diameter. These will capture around 100 times the amount of light your unaided eyes can collect.

Going for higher magnification is not a good idea. It sounds inviting, but this will make the field of view smaller, which in turn makes it harder to find and then stay on the object being observed. In addition, magnification does not just make things in the field of view look bigger. It also magnifies every little shake. For the last few years "image-stabilized" binoculars have been available. These use sensors to detect shaking and a device in the light paths to correct for it, making it much easier to look at things for extended periods. However, these are quite a lot more expensive.

Every backyard astronomer wants a telescope, but making the right choice can be challenging. Getting it right will give many years of pleasure but getting it wrong will lead to another bulky thing that that takes up storage space and gathers dust.

One important consideration is where you live and another is where you will be observing. A permanent observatory in the yard would be great. However, if the telescope has to be manhandled outside, set up, used and then taken down and brought back inside, it might not be used as much.

If the yard is flooded with light, observing might involve putting the gear in the car and driving off to somewhere dark. Portability and ability to set it up at different locations will be important.

If most of the telescope use will be from a light polluted, suburban backyard, then a huge light-bucket might not be a good idea. A smaller telescope, good for looking at the Moon, planets, double stars and star clusters would be better.

For some reason there seems to be less customer protection for astronomical gear than for other things we purchase. There are places that sell unusable junk. To avoid this, don't buy equipment from stores who do not understand what they sell. If possible, go to a science store. Otherwise, there are reputable dealers of astronomical equipment scattered across Canada.

Look on the Internet. It a store sells a wide range of telescopes and other gear, you will probably be all right. And you could be on the way to launching someone into a lifetime of enjoyment and maybe a career in science.

•••

• After sunset, Venus lies close to the SW horizon while Jupiter and Saturn are low in the southern sky. Venus shines brightest and Saturn the faintest.

• The Moon will be new on Dec. 4



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About the Author

Ken Tapping is an astronomer born in the U.K. He has been with the National Research Council since 1975 and moved to the Okanagan in 1990.  

He plays guitar with a couple of local jazz bands and has written weekly astronomy articles since 1992. 

Tapping has a doctorate from the University of Utrecht in The Netherlands.

[email protected]



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The views expressed are strictly those of the author and not necessarily those of Castanet. Castanet does not warrant the contents.

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