In total there are five major events to be observed in the sky this week, though only three can be seen clearly from Iceland due to our position on the planet.
For the rest January, Mercury will be visible. Mercury is the closest planet to the sun and will be most visible right as the sun sets. The planet will set about an hour after the sunset so the window of opportunity for observing it is short. Since it is so close to the sun you can expect to see it very low in the southwestern sky and you will need an unobstructed view in the direction of the sunset. Here in Iceland, Mercury might be a bit harder to see.
At dawn today you should be able to spot a lunar trio in the southwestern sky. The moon will sit to the right of Mars and Spica, the brightest star in the constellation Virgo. Mars will be just 4 degrees to left of the moon and Spica will be just 2 degrees from the moon.
Tomorrow morning, Thursday 23, the moon and Spica will be only one degree apart. Spica is 262 light-years away from earth as opposed to the moon which is 1.5 light-seconds away from earth. The light that we see from Spica tomorrow will have left the star in 1751. To put that in perspective, the light left Spica 32 years before the devastating Laki eruption in 1783 which caused crop failures and acid rain across Europe.
On Saturday, January 25, the moon will sit less than 2 degrees from the ringed planet Saturn. From the southern hemisphere the planet will disappear entirely behind the moon but up north you will be able to spot the ringed planet and a few of its 34 moons with even the most basic telescope.
Lastly, on Sunday morning, January 26, the moon should be perched right above the star Antares. Antares is a bright orange star, about 600 light-years away and roughly 800 times larger than our sun. You will unfortunately not be able to see this from Iceland.
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