Happy New Year, and where the heck did the past decade go? So much has happened in the past ten years it’s hard for us to keep up! We’re all ten years older (and hopefully wiser) and I know I’m desperately hoping that the 2020’s will be classified as the New Roaring Twenties (without the major depression and prohibition obviously!)
This is the first Night Sky blog article of the new decade and hopefully I’ll be able to point out some interesting things for you all to see in the night sky this month.
The first thing to kick off the New Year is something that everybody loves, a good old meteor shower! The Quadrantids Meteor Shower has its peak on January 3rd and 4th. These meteors radiate from the constellation of Boötes the Herdsman. P. Jenniskens wrote in 2004 in The Astronomical Journal that:
“I now find that the shower originated from 2003 EH1, a minor planet discovered by LONEOS on March 6, currently passing 0.213 AU outside of Earth orbit in a high-inclination, comet-like orbit with a Tisserand invariant with respect to Jupiter of only 2.064. The orbit agrees with that of the Quadrantids. Small discrepancies in node (~0fdg3) and perihelion distance (~0.23 AU) are consistent with the differential evolution of comet and debris that was released from 2003 EH1 about 500 years ago into slightly longer orbits. I conclude that object 2003 EH1 is an intermittently active comet.”P. Jenniskens
The first quarter moon will have set below the horizon shortly after midnight on the 4th January and so you should hopefully be able to see come meteors. Even though these meteors radiate from Boötes, they will appear across the sky, with up to 40 meteors per hour!
January 10th will have the first full moon of the decade, and not only will it be a full moon, there will be a Penumbral Lunar Eclipse! A penumbral lunar eclipse occurs when the Sun, Earth, and the Moon are imperfectly aligned. When this happens, the Earth blocks some of the Sun’s light from reaching the Moon’s surface and covers all or part of the Moon with the outer part of its shadow, also known as the penumbra. So, the Moon will darken slightly, but not completely.
The winter constellations will still be in the night sky for your viewing, so why not break out the new telescope Santa got you for Christmas and try and spot some planets and stars! You can also view the Moon on 10th January in its nice full state! On 24th January there will be a New Moon in the sky so this will be the best time to view the stars, as there will be no moonlight blocking your view.
In the South West, around about 6pm (GMT), the Planet Venus will be visible, and it will be a great object to view through your new telescope. Venus is one of our neighbouring planets and is known as the Morning, or Evening Star. This name was given to it by the ancient Greeks and Egyptians.
Later in the night, at roughly 11pm (GMT) you will be able to see the brightest star in the night sky, Sirius the Dog Star, which is part of the constellation of Canis Major the Great Dog. From your telescope you’ll be able to see that Sirius is not just one star, it is two! Sirius is a binary star consisting of a main-sequence star of spectral type A0 or A1, termed Sirius A, and a faint white dwarf companion of spectral type DA2, termed Sirius B. The distance between the two varies between 8.2 and 31.5 astronomical units as they orbit every 50 years.
You will also spot, in the constellation of Orion, the massive star Betelgeuse. It is a distinctly reddish, semiregular variable star whose apparent magnitude varies between +0.0 and +1.3, the widest range of any first-magnitude star. It is one of the largest stars visible to the naked eye, and if it were to be at the centre of our solar system, rather than the Sun, it would expand out past the asteroid belt. In 1920, Betelgeuse became the first extrasolar star to have the angular size of its photosphere measured.
The final star to spot in the constellation of Orion, is the star that marks Orion’s foot, Rigel. It is the brightest star in this constellation and looks blue-white to the naked eye. It is like Sirius the Dog Star because it is not actually one star, but is a multiple system composed of at least four stars! Rigel’s spectral type is a defining point of the classification sequence for supergiants. The overall spectrum is typical for a late B class star, with strong absorption lines of the hydrogen Balmer series together with neutral helium lines and some of heavier elements such as oxygen, calcium, and magnesium. The luminosity class for B8 stars is estimated from the strength and narrowness of the hydrogen spectral lines, and Rigel is assigned to the bright supergiant class Ia.
There is so much more to see in the January Night Sky, but if we were to tell you everything then this article would be roughly 10,000 times longer. The joy of owning a telescope, and observing the night sky, is discovering things for yourself, so I hope these little pointers will help you in your observations!