Don't Back Down

The kids started school Monday. I also purchased some binoculars Monday. Recently I had read about Mars being the closest to Earth it has been in 60,000 years or something, so figured I needed to make a little effort to check it out. I didn't know anything about telescopes other than what I learned in Can't Buy Me Love, so off to Google I went.

One of the sites that came up had a great FAQ on purchasing amateur telescopes. It's pretty lengthy, but it goes into a lot of detail. Specifically, it talks about starting out with a decent pair of binoculars instead of a telescope (unfortunately, it's no longer available online at the prior link). Apparently the department store telescopes that many people buy for $100 or so aren't really worth your effort - and to get a decent telescope is pretty expensive! I did some more searching, and the general consensus was the same: Start with binoculars.

Back to Google I went, this time for more information on binoculars. I found a number of sites on buying binoculars, but several of them seemed to be identical, and perhaps commercial in nature. Still, the information seemed to jive with what I had come across elsewhere, albeit in a prettier format with some ads built in. So I went with them.

The most popular size of binoculars for this type of use seems to be 7x50.

7x means a magnification of 7 times what you get with the naked eye. While there are higher magnifications, you magnify not only the image, but the movements that come from shaky hands. And since higher magnification often means more weight, shaking is bound to increase!

50 indicates the aperture - the size of the front lens - in diameter. In this case, that number is 50mm. Another factor to consider is that the higher the magnification, the darker the image. This might seem backwards, but does make some sense if you think about it. Since the image is only as bright as what you can see, if you magnify the image by 2, you can only see half of the image you saw before - and thus half of the light you had before.

Other factors to consider: The best optics apparently include BAK-4 prisms, which appears to involve a particular coating that improves clarity and definition. It also seems that Porro prisms increase brightness and sharpness of the image.

After doing some more searching, there were not a whole lot of candidates for binoculars that met all of this criteria. I eventually went directly to the sites of some manufacturers and poked around to find some more information. The Minolta Activa WP FP set that I bought fit the bill. There do appear to be other options - but this set seemed to do the trick for me and was in the price range I could afford. Finally I went to eBay to see what was up for auction.

They came in yesterday, so I had my first chance to use them last night in an astronomy setting. They work as well as can be expected inside the city where I am. Lots of light pollution, so not much help on that front. No moon to look at, but we did get a look at Mars. Overall enough to make me want to get a telescope now...