The Slim Moon Slips by Saturn, Some Meteors malinger, and the Pretty Pleiades warns of Winter!
The Moon and Planets
The moon spends this week in the evening sky, growing from a thin crescent hovering over the western horizon after sunset on Sunday, to a First Quarter moon in the southern sky on Friday evening. The entire week will be perfect for exploring the moon’s delights, both visually, and through binoculars and telescopes. The zone along the boundary separating the lit and dark sides is especially enthralling — as this is where the sun’s rays are lighting up peaks and casting long dramatic shadows from them. All this at a convenient time!
The moon will also be crossing the Milky Way while still slim enough not to outshine it. The Milky Way, the concentrated band of stars, gas, and dust that traces the plane of our galaxy across the sky, rises from the southern horizon in evening and arcs overhead towards the north. On Monday night, the moon will sit on the western outskirts of the Milky Way and about a palm’s width to the right of Saturn, which is the medium bright yellowish object partway up the southwestern sky as the evening darkens. Saturn sets in the west about 9 pm local time this week. On Tuesday night, the slightly thicker moon’s crescent will hop to sit squarely within the Milky Way, about a palm’s width to Saturn’s upper left. Finally, on Wednesday night, the moon will land on the eastern edge of the Milky Way.
Blue-green Uranus reached opposition and peak brightness last Thursday, when the Earth moved directly between it and the sun, making us closest to it for the year. It is situated between the two chains of stars that form Pisces (the Fishes). It’s about two fist diameters (20°) above the southeastern sky at dusk and observable for the rest of the night in binoculars under a dark sky (or telescopes, the rest of the time) as it crosses the sky. To help guide you, there’s a medium-bright star called Omicron Piscium a generous finger’s width to the lower left of Uranus. Viewing the planet on any evening for a week or two on either side of opposition is nearly as good.
Tiny blue Neptune is located in the southern evening sky about half a finger’s width below the medium-bright star Hydor in Aquarius (the Water-Bearer). It is observable from full darkness until midnight, but it is too faint to be seen without a telescope.
This week, extremely bright Venus continues to drop daily in the eastern pre-dawn sky as it swings sunwards. The planet should be easily seen for about an hour, once it rises at about 6 am local time. Much dimmer and reddish tinted Mars sits about a fist’s diameter to the upper right of Venus. Mars rises about 5 am, an hour before Venus.
Bright Stars to Look For
As the evening sky darkens, a number of bright stars will pop into view this time of year. The Summer Triangle, composed of the stars Vega in Lyra (the Harp), Altair in Aquila (the Eagle), and Deneb in Cygnus (the Swan), are still prominent in the southwestern sky after dark. Aquila, on the bottom left (south) sets around 1:30 am and Vega, on the right (north) sets around 3 am local time. Deneb, which marks the swan’s tail feathers, is the highest of the three and nearly overhead in mid-evening. The great bird truly appears to be flying south for the winter, down the starry river of the Milky Way, until it returns late next spring.
The very bright star twinkling low in the west until about 8:30 pm is Arcturus. Unlike airplanes, Arcturus won’t flash on and off, or move left to right.
Turning to face north, you’ll see the Big Dipper practically resting flat along the northern horizon. Looking farther to the right (or east), the very bright star, yellow Capella will catch your eye. Capella is the first harbinger of our favorite winter constellations. Its home constellation, roughly circular Auriga (the Charioteer) leads Taurus (the Bull), and then Gemini and Orion, up from the east as the evening wears on. After 8 pm, you should be able to spot the bright little Pleiades star cluster, also known as the Seven Sisters and M45, low over the eastern horizon.
Orionid Meteor Shower
The excellent annual Orionid Meteor Shower peaked this weekend, but you can continue to watch for a reduced number of them until the shower officially ends on November 14. The meteors can appear anywhere in the sky, but will only be true Orionids if they are moving in a direction away from a location (the radiant) above the bright red star Betelgeuse in the constellation of Orion. Although not too prolific, Orionids are known for being bright and fast-moving. Happy hunting!
From now through the end of October, the nearly vertical morning ecliptic favors the appearance of zodiacal light in the eastern sky for about half an hour before dawn. Look for a broad wedge of brightening centred on the ecliptic (i.e., surrounding Venus and Mars). It’s reflected sunlight from interplanetary particles that are concentrated in the plane of the solar system. I posted a picture here.
Stargazing News for this week (from October 22nd, 2017) by Chris Vaughan.