What’s new for October? What to look for this month at sunrise and sunset, and two bright stars vying for the “pole” position.
On October 10, look for the five-day-old crescent moon to join the bright orange-colored Venus and Antares in the southwest after sunset. Then watch Venus close on Antares, for a close conjunction on the 15th and 16th, where the two will only be about a degree and a half apart.
Venus approaches about 1.5 ° to the bright orange star Antares on October 15 and 16, about an hour after sunset. Credit: NASA / JPL-Caltech
During the last week of October, Mercury appears briefly for early risers.
Look for it about 10 degrees above the eastern horizon, or about the width of your fist held at arm’s length, about 30 to 45 minutes before sunrise.
During the last week of October, Mercury can be seen briefly in the morning sky before sunrise for those with a fairly clear view of the eastern horizon. Credit: NASA / JPL-Caltech
Then on October 30, in the last hours before sunrise, search for the 24-day crescent moon to join the bright blue-white star Regulus.
Find the crescent moon near the bright star Regulus in the east before dawn on October 30. Credit: NASA / JPL-Caltech
Throughout the month, look high above your head early in the evening to find two bright stars taking turns with Polaris being the pole star. Their names are Vega and Deneb. These two stars are part of the Summer Triangle, and we featured the other trio member, Altair, in last month’s video. To find Vega and Deneb, look overhead in the first few hours after dark. They’ll be two of the brightest stars you can see up there.
In October, look high above your head to find the bright stars Vega and Deneb within a few hours of sunset. The pair are turning west, lying in the hours before dawn. Credit: NASA / JPL-Caltech
Vega is a bluish-white star, and like Altair, it is a fast rotator, rotating every 12 and a half hours, compared to the Sun’s 27-day rotation. NASA’s Spitzer Space Telescope discovered that Vega was surrounded by a disc of debris that may be similar to regions of our own solar system.
Deneb is a blue-white supergiant star that is fusing hydrogen at a phenomenal rate.
With that kind of fury, the party won’t last very long. Deneb is likely headed for an explosive end as a supernova within a few million years. Deneb is much further away than most of the bright stars in our night sky. It means it’s SUPER bright to be this bright from so far away. Because it is so bright, it is one of the farthest stars you can see with the naked eye.
These stars revolve around the north celestial pole, and at this time of year they dip toward the western horizon before setting before dawn. Vega and Deneb are part of a special group of stars that are in turn the pole star in the north, as the Earth’s axis oscillates in a circle over a 26,000-year period. For now, the “North Star” distinction has belonged to Polaris, for at least a few hundred years more.
Over 26,000 years ago, Polaris traded the title of North Star with a group of others, including Vega and Deneb. Among these special stars, Polaris is the bright star that most closely coincides with the celestial North Pole. Credit: NASA / JPL-Caltech
Finally, October 16 is International Moon Watching Night, when everyone is invited to learn more about the science and exploration of the Moon. Visit this link to find out how you can participate.