Heliacal rising
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The heliacal rising of a star or a planet occurs annually, when it becomes visible above the eastern horizon at dawn in the brief moment just before sunrise. A heliacal rising marks the time when a st
Sirius is the fixed star with the greatest apparent magnitude and one which is almost non-variable. The Pleiades, a key feature of Taurus shown across Orion in the same photograph also experience an annual period of visibility ("rising and setting"). Photo taken at sunset.
Dog days
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The dog days or dog days of summer are the hot, sultry days of summer. They were historically the period following the heliacal rising of the star system Sirius, which Hellenistic astrology connected
Heliacal rising
…and acronycal is not consistent. The following table gives an overview of the different application of the terms to the rising and setting instances. Dog days Steering star…
Vegetation on Crete dried out by the August heat
A 9th-century astronomical manuscript, including an illustration of the constellation "Canis Major"
"Some Popular Alleviations of the Dog Days in Hotter New-York" in 1904, including children piled into a public fountain "when the 'cop' is not looking".
Orion (right) and Sirius (bottom), as seen from the Hubble Space Telescope