![]() In this blog post, we'll take a closer look at the Big Dipper constellation, its history, mythology, and key features, as well as tips for viewing it in the night sky. Its distinctive shape and prominence make it a favorite among stargazers and astronomers alike. The Big Dipper, also known as the Plough or the Great Bear, is one of the most recognizable and beloved constellations in the night sky. If we made the horizon line straight, the geometry of objects in the sky would be distorted.The Big Dipper Constellation: A Guide to the Stars in the Sky The horizon line is curved in order to preserve the geometry of objects in the sky. As you turn your head from side to side, you will be looking in the compass direction indicated by those numbers. The numbers along the white “Your Horizon” curve at the bottom of the map are compass points, shown on degrees. When getting your bearings under the stars, it’s often easiest to spot an asterism and use it as a guide to finding the parent constellation. These are distinctive star patterns that lie within constellations. The items labeled in green on the sky map are known as asterisms. If you are substantially south of these areas, everything on our map will appear higher in your sky. If you are located substantially north of these areas, objects on our map will appear lower in your sky, and some objects near the horizon will not be visible at all. states, southern Canada, central and southern Europe, central Asia, and Japan. The map is accurate for any location at a so-called “mid northern” latitude. For example, if the map legend says “Looking Southeast,” you should face southeast when using the map. The legend on the map always tells you which direction you should facing, based on midnight viewing. Instead, the monthly map focuses on a particular region of the sky where something interesting is happening that month. Our sky map does not show the entire sky which would be almost impossible. Sky map produced using Chris Marriott’s Skymap Pro How to Read the Sky Map So, for thousands of years at a time, we have NO North Star at all! December Sky MapĬlick here or on map below to enlarge ( PDF). And in 26,000 years, the axis will once again point at Polaris, making it our North Star once again.įor much of the 26,000-year period, the Earth’s axis points to no bright stars.Looking ahead, about 13,000 years from now, the Earth’s axis will point toward the bright star Vega, which will then be our North Star. ![]() For example, between 4,000 and 6,000 years ago, the Earth’s axis pointed at Thuban, a star in the body of Draco, and so Thuban was then the North Star.Over a period of about 26,000 years, the Earth’s axis traces out a huge circle on the sky, and over time it points toward bright stars other than Polaris, as shown on the inset on our map. This means that the axis of the Earth does not always point at Polaris. It turns out that the Earth wobbles slightly as it spins through space, just as a spinning toy top wobbles as it slows down. On a cosmic time scale, different stars take turns as our North Star. These six circumpolar constellations perpetually chase one another around Polaris. Draco, the Dragon (whose four-sided head is especially distinctive).Cepheus, the King (looking like a child’s drawing of a house) and.Cassiopeia, the Queen (with her distinctive Big W or M shape).Ursa Major, the Greater Bear (including its Big Dipper asterism).Ursa Minor, the Lesser Bear (including Polaris).There are six of them, highlighted in green on our map: The constellations close to Polaris are thus visible all night and every night of the year for observers at mid-northern latitudes, such as the 48 United States and much of Europe, and are known as circumpolar constellations. This movement is caused entirely by the rotation of the Earth on its axis.Ī few constellations are near enough to Polaris that they never drop below the horizon, as do constellations farther from the North Star. All of the other stars on the map will have moved, too. If you waited six hours-until 2:00 a.m.-and look at the northern sky again, the Big Dipper will have revolved to a position directly to the right of Polaris. Note the Big Dipper, located at the bottom of the map, directly below Polaris at 8:00 p.m.And just as with a clock, the movement is slow. The stars of the northern sky appear to rotate counter-clockwise around Polaris.
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