Skywatch: Look for the "ghost of the summer sun" this week


If you’re out at nightfall on Sunday and skies are clear enough look for the solar system’s largest planet passing by the planet that’s closest to the sun. Jupiter and Mercury will be in the evening sky near the horizon in the west-southwestern sky. Jupiter will be just above and right of Mercury. Get out early to find the two because they’ll be setting shortly after it gets dark. Just above and left of the pair you’ll find Saturn.

While researching this week’s Skywatch I learned something new about one of my favorite stars, Arcturus. Arcturus is the brightest star in the Bootes, or the Herdsman. The star has an orangish hue and this week it rises and sets at the same time and the same place in the sky that our sun does during the “dog days” of summer. This happens every year on Halloween and that’s why Arcturus is also known as “ghost of the summer sun.” Use the handle of the “Big Dipper” to help you find it.

The Last Quarter Moon will arrive on Halloween at 12:40 p.m. Look for the half-moon if you’re out trick-or-treating.

If the moon looks a little bigger than you’re used to on Halloween that might because the moon reaches perigee Wednesday night. Because the moon’s orbit is not an exact circle there are times when the moon is closer to and farther away from the Earth. The perigee is the point when the moon is closer in its orbit. At 4:23 p.m. Wednesday the moon will “only” be 230,034 miles from us. This happens every month but what makes this perigee special is that’s the farthest one of the year. Simply put, it’s the farthest close moon of 2018. When it’s high in the sky you won’t notice it but if you see it near the horizon it may look just a shade larger than you’re used to. Happy hunting!