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Observing the Planets with Binoculars

Everyone should own a decent pair of full-sized binoculars, and not just because they will enhance the views of our biggest and brightest planets.  A good pair of binoculars will serve you well throughout your life and allow you to enjoy concerts, sporting events, wildlife, travel, as well as the night sky more fully.  

There are a few things to consider when choosing or using binoculars, or in any other situation where your available light is very limited.  The first consideration is the size of the optics.  The larger they are, the more light they will deliver to your eyes.  We recommend binoculars with an aperture of at least 50mm for the best performance when enjoying the night sky.  Smaller apertures will produce a dimmer view, and larger apertures will deliver increased brightness and more detail.  

Second, keep your aperture-to-magnification ratio to around 5mm-7mm.  To figure this out simply divide the aperture by the magnification; for example, a pair of 7 x 50 binoculars would have an aperture-to-magnification ratio, called the "exit pupil", of a tad over 7 (50mm divided by 7 equals 7.14mm).  Why is this important when using binoculars at night?  Because when you are doing astronomy darkness is usually a prerequisite and given time, your eyes will dilate as much as possible to help you see better.  The maximum size of your pupil when fully dilated is approximately 5mm - 7mm and so if you have binoculars that send a similarly sized beam of light to your eyes, you will receive the maximum amount of light you can get, and that translates to more detail and a better experience.   This is why a good pair of 7x50 binoculars is super popular with amateur astronomers, even if they have a telescope.

Finally, consider the possibility of mounting your binoculars on a tripod.  You don't need a special tripod to do this; most camera or video tripods would work just fine.  The accessory you will need is something to connect the two (binocular and tripod).  That piece is called a Binocular Tripod Adapter and it doesn't have to be fancy or cost very much.  Almost all medium and full-sized binoculars have a built-in adapter port, although it may go unnoticed because it is covered with a thread-on beauty cap.  To mount your binoculars to a tripod adapter, simply unthread the beauty cap (assuming there is one), thread the screw on the adapter into the adapter port, and attach the other end to your tripod.  Adjust the tripod legs so that you can comfortably look through your binoculars and voila, you'll be able to look at the planets, the Milky Way, the Moon, and some bright nebulae, galaxies and star clusters without experiencing arm fatigue and shaky views. 

Here is a list of binoculars that would work well for daytime as well as nighttime.  If you have any questions, please feel free to contact us by chat, phone, or email.  

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