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Monthly Archives: September 2007

27 Sep

Even if you are not an astronomer, the night sky is a great place to test a binocular for resolution, color correction, edge sharpness and so on. Bright stars are a tough test for any optic and only a quality binocular will show a star as a tiny, perfect pinpoint of light with no color halo. An average binocular will typically show a star as coma shaped or with spikes (flares) and only the finest binoculars will be free of color fringing. Another great test for color fringing (chromatic aberration) is the edge of the moon. It is a rare …

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26 Sep

When we recommend astronomy binoculars, the general guideline is to have a binocular with enough image brightness to make it practical to see the faint objects that are often the targets in astronomy. This is generally defined as a binocular with an exit pupil (second binocular number divided by the first) of at least 4 or 5. Does this mean you cannot use a binocular with a smaller exit pupil, say an 8×20 compact binocular with an exit pupil of only 2.5 (20 divided by 8)?

The answer is that any optical instrument, even small compact binoculars, will show you …

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25 Sep

We all develop daily routines, sometimes by default and sometimes by design. One of the things that I do by design when night falls, weather and sky permitting, is to end my day out on the apartment patio with my astronomy binocular. Sometimes I get involved in an astronomy project and put in a couple of hours of serious observing, but most evenings it’s a more casual – just me saying thank-you to Earth Mother for another wonderful day and honoring the sky and stars above with a quick peek or two through the binocular. A binocular is the perfect …

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20 Sep

If my neighbors weren’t talking before, I’m sure they are, now.

Last night I was experimenting with a Celestron OIII filter in front of one of the eyepieces on my Nikon 10×70 Astroluxe bincoular – not something either item was designed to do and not a technique I recommend as a regular practice – but it did work to better show M27. What was previously the dimmest spot for this planetary and something visible only because I knew exactly where it was, became an obvious planetary nebula with a filter carefully placed in front of the eyepiece of the binocular. …

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19 Sep

One of the less appreciated advantages of using a binocular for astronomy, compared to a telescope, is the relative ease of use of the binocular for observing objects directly overhead. In many telescopes, objects directly over head can sometimes not be accessed because of mount clearance issues or, when a telescope can be lined up, it is difficult to find though the viewfinder and also track. I know, because I have the neck aches to prove it. On the other hand, nothing is quite so easy to use for overhead objects as a binocular in your hand as you are …

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18 Sep

Ever wonder how much performance and quality you need in a binocular to be happy? What level of image quality will satisfy you?

You can get a handle on binocular performance in a number of ways. For instance, it’s easy to examine features and get a rough idea of binocular performance potential. You can also read binocular reviews that rate and compare binoculars with similar features. If you are really ambitious, you can head to a store and get binoculars in your hand. Then, too, there is always price as a guideline. An expensive binocular should offer great optics and, …

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17 Sep

There was a day when you had to search carefully for a binocular that was suitable for use with eyeglasses. In the “good old days” those of us with “four eyes” had a limited selection when shopping for binoculars. Fortunately, the situation has reversed itself and, now, binoculars with enough eye relief for use with eyeglasses actually outnumber those that do not have the requisite eye relief of 15mm or more. Maybe it’s because the manufacturers are just being nice to we birders who wear glasses. Okay, it’s more likely the binocular manufacturers realize that the majority of their customers …

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13 Sep

Amateur astronomy doesn’t really have a “season” as such – each season of the year brings us new and fun things to observe and each season has its appeal. The shorter days of fall, however, makes astronomy a bit more practical for many of us working folk. The ability to get out and observe and still get to bed at a decent hour is one thing I especially like about fall and winter observing. Summer is great, but it’s tough to get motivated when you can’t even start to observe until after 10:00 PM. Ouch.

Last night was the nearly …

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12 Sep

Although I’ve been sorely tempted to forsake a binocular for a monocular to save weight, I know better for serious work like birding. Oh sure, I’ve spotted a lot of birds with my Nikon 5x15HG monocular, simply because it was the optic I had with me while bicycling or doing other activities, but use a monocular full time for birding?

Not going to happen. Fall warblers are tough enough to identify and follow with a binocular; I’m not about to add to the challenge by losing the use of one eye with a monocular. I have been known to compromise …

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11 Sep

The warblers are on the move, here in the Chicago area. A friend of mine who works in bird rehab runs a route in downtown Chicago to rescue birds that have collided with tall buildings at night during migration. She reports an increase in birds rescued this last week, especially warblers. This, of course, is a little hard to hear without cringing, but it does mean it is time to head to the local Forest Preserve and do some birding.

I own and use binoculars of all magnifications, but for fall warblers, I have been partial to 7x and 8x …

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