You'll always know it's Sirius if the very noticeable constellation Orion the Hunter is nearby.
The first hints of the changing of the seasons can now be seen in the predawn and dawn sky: Orion the Hunter and Sirius the Dog Star. The very noticeable constellation Orion the Hunter rises before dawn at this time of year, and Sirius follows Orion into the sky at or close to dawn. Orion will become visible in the evening by winter, but presently the Hunter lords over the southeastern sky at dawn’s first light.
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Orion was low in the west after sunset last spring, and, in early summer, this constellation was behind the sun as seen from Earth. Orion only returned to visibility in Earth’s sky about a month ago. (See our July 30 sky chart.) When a constellation becomes visible again, after being behind the sun, it always appears in the east before sunrise. Because – as Earth orbits the sun – all the stars rise two hours earlier with each passing month, Orion is now higher at dawn than a month ago.