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Re: (meteorobs) Fwd: Oct. 18 in the Northwest
Hi, Marcia - glad you were able to get out a little the other night!
If you get more clear weather this week, try for some early morning
observing too - you should see much more going on that way!
>The trail was 6 1/2 inches long (not sure how to measure...)
Don't worry too much about measuring distances right now, Marcia. But
you might want to practice measuring meteor BRIGHTNESS - this is quite
a challenge when you're first starting out! Start off tring to guess
the brightness of some of the stars you see in the sky: you can check
your guesses against most star atlases. Then when you see meteors try
to compare their brightness with that of your known stars!
Anyway, astronomers use sky angles to measure distance - To see why
this is, just imagine your string: if *you* hold it at arms' length, it
might appear 10" long to you. But if someone with longer arms uses the
same string at arms' length, suddenly it only seems 8 inches long!
Sky angles are measured in degrees - the best way to learn these is to
memorize a few distances among the constellation: the "top of the bowl"
of the Big Dipper is a nice even 10 degrees long. The distance between
the two "Eyes" of Draco the dragon is a fair 4 degrees. The height of
the "Sickle" in the head of Leo is just about 15 degrees. The distance
from the "nose star" of Taurus to either "Horn Star" is about 20 degs,
and 20 degs is also the diagonal size of the Great Square in Pegasus!
And finally, there are almost exactly 2 degrees between Beta and Gamma
Lyrae, the two "bottom" stars of the pretty little Harp.
Clear skies all!
Lew
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