Saturday, June 24, 2006

Dark Skies & Things That Go Bump in the Night

It is really dark up here. I dragged Big Bertha out of the garage Wednesday night, trying to find M51 (the Whirlpool Galaxy). No luck. I'm sure it's dark enough--I just need to spend a bit more time with the locator charts that show where it is relative to nearby stars.

I confess that I have never put much time into looking for deep sky objects (i.e., galaxies, nebulae, and other faint fuzzy bodies) because I have never lived somewhere dark enough for this to be useful. Now I do--but that means that I have to learn where these objects are.

As an example, M57 (the Ring Nebula) is a planetary nebula in the constellation Lyra. It is bright enough that you can find it from almost any suburban location--and you don't even need a huge telescope to see it. I saw it (with averted vision) with my Televue Ranger, which only had a 70mm front lens. But to find it, you need to know where to look. It is on a line between Beta Lyrae and Gamma Lyrae, about 2/3 of thw way between them. If you start out with too low of a power on most telescopes, you won't see it, because it is pretty small, and you may not be able to distinguish it from a star. If you start with a high enough magnification to see that it is a smoke ring, not a point source, you have to pretty much on it, or you will be wandering through the celestial neighborhood, and never hit it.

The same is true for most other deep sky objects--some are barely visible with the naked eye (and most are not), so you need the light gathering ability of a telescope to have any hope of finding them.

Anyway, because I knew where to look for M57, I had no problem finding it with Big Bertha. Even with a low power eyepiece (about 80x), M57 was obviously not a star. On a smaller scope, you can't really go up much above 100x, because the image becomes too faint to see. (Higher magnification with the same amount of light yields contrast problems.) With Big Bertha, even at 222x, M57 was still easily visible.

Along with the darkness of the sky, there is the darkness that brings out critters. Thursday night our dog went absolutely bananas in the wee hours, barking ferociously at the sliding glass door in the family room. My wife couldn't see what she was barking at--but the front motion detector lights came on as well. (I slept through it.) What was it?

Today I was walking back from the mail box, and ahead of me on the road was what at first looked like a small dog--but turned out to be a coyote. Conforming to their reputation as being shy and retiring creatures, it bounded up the hill along the boundary line between our parcel and lot 3 to the south.

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