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Backyard Astronomy
The Moon

If you're just starting with backyard astronomy, why not start with the moon? I know it might seem a little boring, but it's not. Let's look at some of the rewards you'll get by selecting this object as your first astronomy target.


It's easy to find.


It's easy to predict if it will be in the sky, and where.


With inexpensive binoculars, you'll be able to see more detail on the moon than with any other night-sky object, even with a very expensive telescope.


Light pollution is not an issue with the moon.


You don't have to worry about dark-adapting your eyes.


Inexpensive moon maps are available.

Full moon, not magnified. Click to enlarge.Now the full moon (left, non-magnified) is the bane of backyard telescope astronomers. Its bright light washes out all of the dim "fuzzies", such as galaxies and nebula, as well as detail on planets. Unless, of course, you're studying the moon itself. Since the moon always puts the same face towards us, what you see in one full moon is what people have been seeing in full moons for thousands of years.

So, even this beast has its uses. Using your binoculars, and an inexpensive moon-map (about $9 at Amazon), you can start identifying the craters and seas (mara). You will, of course, want to find the Sea of Tranquility, the landing site of Apollo 11.

Magnified moon along terminator. Click to enlarge.But you can catch the moon between the rising crescent and the first quarter (halfway between new and full), and use some binoculars on the "terminator" - where light meets shadow - all of a sudden the moon isn't boring at all. It comes alive as shadows in a landscape of mountains, valleys and craters.

And, if you catch the moon around the crescent phase, or a couple days after, you'll see something really special. The crescent part of the moon is lit, but you can still see the rest of the disk, darkened. This is called "earthshine". You're seeing this dark part of the disk because of light reflected off the the Earth and back to the moon. It only lasts for a couple of nights, but you can impress your friends with this fact alone.

For binoculars, if you don't already have a pair, you can probably find a neighbor that does. A good choice is a decent set of 10X30 binoculars. The 10X means a magnification of 10, and the 30 is the millimeter diameter of the objective (front) lens.

If you are buying a pair of binoculars, don't get carried away. The most important quality of a binocular (besides the optics) is you must be able to hold them steady. This means avoid such things as 20X80, because you'll need a tripod or some other steadying device for those things.

For backyard astronomy, the moon is a logical, rewarding, and (best of all) inexpensive way to start.
























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