This is Dudley Observatory’s Skywatch Line for Friday, January 8, through Sunday, January 10, 2016, written by Alan French.
The Moon reaches new early Saturday evening, so this weekend’s skies will be dark and moonless. Watch for the slender young Moon as it returns to the evening western sky early next week.
At 6:30 am on Saturday morning Saturn and Venus will be very close together in the southeast. They will be just under one-half degree apart, less than the apparent diameter of the Moon. Fainter Saturn will be to the upper right of Venus. The rapid motion of Venus among the stars will speedily move them farther apart over the next few days. By Sunday morning the distance between the pair will have increased to one and a half degrees. By Monday they will be two and a half degrees apart.
If you’re up a bit earlier on Saturday morning, watch the International Space Station (ISS) as it passes low across the northern sky. The station will first appear at 5:58:23 am when it will emerge from the Earth’s shadow in the north northwest when 28 degrees above the horizon. It will travel eastward across the northern sky, passing above the conspicuous “W” of Cassiopeia, the Queen, and then vanish below the northeastern horizon at 6:01:29.
In the evening the Pleiades, also known as the Seven Sisters, is well up in the sky. Look for it high in the southeast at 8:00 pm. The cluster has the shape of a small dipper, and is above and somewhat to the right of bright, reddish Aldebaran.
To the eye, the Pleiades is a lovely sight, but under our dark moonless weekend skies binoculars will reveal many more stars, transforming it into a real celestial showpiece. It is one object that is often best seen in binoculars. Their wide field of view will show the entire cluster surrounded by darker, less star strewn sky. Most telescopes do not show enough sky to encompass the entire cluster in one view.
The Pleiades has been known since antiquity. Homer wrote about it in the Iliad and Odyssey. To some Greek astronomers its stars formed a distinct constellation. In Japan it is know as “Subaru,” and you can recognize the cluster in the company’s logo, visible on their cars.
As early as 1676 Reverend John Mitchell realized the stars in the cluster must be physically related by calculating that the odds were strongly against so many bright stars being close together in a chance alignment. Comet hunter Charles Messier included the Pleiades in his catalog of deep sky objects. As the 45th object on his list amateur astronomers often refer to it as M45. Whatever you call it, it’s one of the finest sights in our night sky.