![]() The Big Dipper twinkles over the snow-covered Alborz mountain range in Iran. In addition to its role as a sort of cosmic chronometer, the Big Dipper can also serve as a calendar. From the relative position of the Big Dipper with respect to Polaris, the season of the year - and eventually with practice, even the month - can be determined by looking at the sky.ĭuring the hours just after darkness falls in the spring, we can find the asterism soaring high above the northern horizon and stretching to the point almost directly overhead (the zenith). But by summer it has turned counterclockwise by 90 degrees the bowl now points downward and it lies to the west of the pole during the early evening hours.īy fall evenings, the Big Dipper is far beneath Polaris and skims the northern horizon. This position in the sky is appropriate in a way, as bears are going into hibernation at this time of year, and as we mentioned earlier, the Big Dipper is part of the big bear constellation, which is now partially hidden below the northern horizon. And now, during the winter we find it ascending the sky once again, standing on its handle around 9 p.m. ![]() A yardstickįinally, another valued and fascinating use of the Big Dipper is that we can use it as a convenient astronomical yardstick by which we can measure angular sizes and distances (opens in new tab) in the sky. ![]() Sky angles ranging from 5 to 25 degrees in extent can be determined using the stars of the Big Dipper.
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