The sky this week for October 5 to October 7
The Moon reaches perigee, the closest point in its orbit around Earth, at 6:31 p.m. EDT. It then lies 227,665 miles (366,392 kilometers) from Earth’s center. At the same time the Moon is at perigee, Regulus, the brightest star in the constellation Leo the Lion, lies 1.9° south of our lone natural satellite.
Saturday, October 6
Although it’s low, Saturn remains a tempting target in this week’s evening sky. The ringed planet stands nearly 20° above the southwestern horizon as darkness falls. Shining at magnitude 0.5, it appears significantly brighter than any of the background stars in its host constellation, Sagittarius the Archer. Of course, the best views of Saturn come through a telescope, which reveals a 16″-diameter globe surrounded by a spectacular ring system that spans 36″. But more significantly, look specifically at how much the rings tilt to our line of sight. The rings are quite open now, and the steep angle offers superb views of ring structure.
Sunday, October 7
Vesta, the brightest minor planet, is super easy to find tonight, low in the southwestern sky. Use a small telescope (or tripod-mounted binoculars) and point to magnitude 2.8 Kaus Borealis (Lambda Sagitarii). If you are familiar with the famous Teapot asterism of Sagittarius, Kaus Borealis is the star at the peak of the pot’s lid. As soon as it’s dark enough for you to locate the orange star, center it in your scope’s field of view. Vesta will then lie only 20′ (one-third of a degree) to the south.