The glow of Canopus will flood the south of the nocturnal celestial vault and shine with all its intensity. It will be the second brightest in February.
The brightest star is, undoubtedly, the Sun. It reigns over the Earth’s sky and brings us its warm energy. At night though, the story changes drastically. The darkened dome is dominated by the Moon, Sirius, and Canopus. These last two are the two brightest stars at night.
Sirius is widely known for being the alpha of the night; it is possible to admire it from anywhere on Earth. The star, which belongs to the constellation Canis Maior, has an apparent magnitude of -1.46, which means that it is the brightest of the entire starry night.
Canopus, which belongs to the constellation of Carina, is the second most visible star in the sky with an apparent magnitude of -0.72. It’s important to remember that the magnitude scale goes down: the smaller the magnitude, the brighter the star.
Canopus, the Southern Star
Although Sirius is impressive for its brightness, Canopus is special because it is the alpha of the southern horizon on the celestial map. In fact, it has been used for centuries as a reference to locate this cardinal point by the oldest navigators and thus avoid getting lost in the blackness of the night.
Its name in the constellation catalog is Alpha Carinae, which means that it is the most luminous star in the constellation of Carina. It has a magnitude of -0.72, making it the second brightest apparent star, only behind the untamed Sirius. The first records of Canopus date from approximately 2,300 years ago, when the Syrian astronomer Posidonius calculated its position near the southern horizon.
According to the European Space Agency, Canopus is located at a distance of 310 years from Earth, and it is an F0-type star, also known as a bright giant. It is a much more explosive star with temperatures higher than our Sun. It is estimated that Canopus is so large that it would take the mass of 65 suns to make it equal to its size.
How to Find Canopus in the Celestial Vault
It is impossible to watch Canopus from the northern hemisphere. If you want to admire its explosive brilliance, you’ll have to travel south. In the celestial vault, from the southern perspective, you need to look south to admire the constellation of Carina and look for its largest star.
One of Canopus’ main characteristics is its location. It is located far to the south, so it never rises above the horizon, no matter how late at night it es. It follows a circular path just due south. That is the reason the star is used as a compass to locate south since it’s always found in that direction.
Story originally published in Spanish in Ecoosfera