For stargazers, the Big Dipper is a celestial compass, clock, calendar and ruler. Here’s how to use it.

rod

Oct 22, 2019
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The Dipper is more than just a bright and familiar star pattern. It's a compass, a clock, a calendar and a ruler all rolled into one!

For stargazers, the Big Dipper is a celestial compass, clock, calendar and ruler. Here’s how to use it. : Read more
"We can also use the Dipper as a celestial clock. In his book "Star Lore of All Ages" (G.P. Putnam's Sons, 1911), William Tyler Olcott, the early 20th century American lawyer and amateur astronomer, wrote: "The entire figure of the Great Bear circles about the pole once in twenty-four hours. This is, of course, an apparent motion due to the rotation of the Earth. A line connecting the 'pointer stars' with Polaris may be regarded as the hour hand of a clock. With a little practice, the time of night can be ascertained to an approximate degree by the position of this stellar hour hand."

Enjoyable report. In March, there are times when I stargaze, I sit outside in a lawn chair and watch the Big Dipper circle around Polaris through the night, you can see this happen over several hours or more and see the Earth's rotation taking place. I periodically use my telescope and view the double star Polaris at high power, > 100x and compare to other stars like Mizar or others. Those stars will zip across the eyepiece FOV as the Earth spins while the Polaris double does not. If you live near 38 or 39 degrees north latitude, Polaris will be near 38-39 degrees evelation or altitude and near 360 degrees azimuth.
 

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