"C" == Chuck writes:

C However, I have read about the complex system that the astronomy
C community uses, which is necessary to figure directional reference
C in the universe. Like others, I have a very general idea of how it
C works, but still lack much in the way of being able to think of it
C in a practical manner.

The most common one is right ascension and declination. The essential
element of it is not all that complicated. The sky looks like the
inside of a sphere. Imagine that the Earth were made of glass, with
the latitude and longitude lines painted on it and that there is a
powerful lamp at the center of the Earth. Then the shadows of the
longitude and latitude lines would form the lines of right ascension
and declination, respectively.

The complex part comes from the Earth's rotation, revolution, and
precession. The right ascension and declination of a star does not
change (ignoring precession, which is a slow effect), even though it
rises at different times during the year.

C It would seem that in some way a method could be devised so that
C any of these coordinates might be better visualized. For us
C laymen, one of many confusing things about the universe is there is
C no up or down -- north, east, south or west.

I think there is a constellation site that has a Java applet with the
right ascension-declination lines overlaid.

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