Under The Martinborough Stars
Twinkle Twinkle Little Star,
How I wonder what you are,
Up above the World so high,
Like a Diamond in the sky
Twinkle Twinkle Little Star
How I wonder what you are
Whenever I hear this child’s song, I often think of Sirius, the brightest and twinkliest star in the sky. It is easily the brightest star in the sky over Summer and Autumn. It is a particularly beautiful white and diamond-esque star and well-known throughout the world, named colloquially as the dog star.
Sirius is also called Alpha Canis Majoris or the Dog Star, brightest star in the night sky, in Autumn you can find it heading towards the North West. Stars are named using the Greek alphabet, Alpha for your brightest star in the constellation- here being Canis Major, followed by Beta, Gamma, Delta etc. One positive from COVID is that we are all getting pretty good at our Greek alphabet over the last two years.
Like most of the stars we see in the sky, it has a companion star, imaginatively named Sirius B. Sirius A is the brightest of the pair, a blue-white star, 25 times as luminous, larger and much hotter than our own Sun. Its distance from us is 8.6 light-years away, meaning the light has taken 8.6 years to reach us, travelling at the speed of light. In comparison our Sun’s light takes only 8 and a half minutes to reach us travelling at the same speed.
Astronomy is all about reading the sky, to work out when to do things, it’s basically a giant calendar. For example, when Sirius made its first heliacal rising in Egypt (i.e., rose just before sunrise) of the year, it was coincidental at the same time that the annual floods were beginning in the Nile river delta. They long believed that this star actually caused the Nile floods.
Here in New Zealand, it is often known as Takurua, the ‘Winter Maiden’ as it rises in the morning sky to the right of the star cluster Matariki in June.
Sirius- the star and the word can be found all over the place. It’s named for ships, on flags, coats of arms, cars, radio stations, and is hugely popular in sci fi. But you probably recognise the name from Harry Potter, Sirius Black who can turn into a black dog (sorry spoilers!)
So over the next few weeks, when Orion is still in the sky, trace through the three belt stars of the constellation up and right and you will land straight on Sirius. Using constellations to find other stars is called star hopping- give it a go next time you are out. Can you make out the shape of the dog?
Becky Bateman, owner of Under The Stars, an award winning Wairarapa Astro-Tourism business
Image credit: NASA
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