October Meteor Showers
When is the last time you remember observing a decent display of shooting stars? Either the weather or a bright Moon has conspired to prevent us from indulging in this simple and inexpensive aspect of amateur astronomy. Perhaps you took advantage of the dark skies seen around Southern New England during the power outages caused by Tropical Storm Irene? On the Monday night (29th) following the storm, I observed about six meteors per hour before midnight. These meteors were not associated with any specific shower peak, though I did count a few Perseids among them.
Hopefully others who had an opportunity to look up at the night sky noticed the beauty of the heavens once all the lights had been extinguished. Maybe then they will be encouraged to turn off some outdoor lighting to allow starlight to awaken a new generation of young stargazers.
October provides two observing windows to observe more than a handful of shooting stars blazing across the night sky. First up is the Draconid meteor shower on the night of October 8-9. The Draconids are normally a minor shower, with ten or less yellowish meteors per hour at peak. These particles are fairly slow moving, hitting our atmosphere at only 12.5 miles per second.
However, one Canadian astronomer has predicted that the Earth might pass through a narrow but dense part of the meteor stream. Why? The Draconids are particles that were stripped off short-period (6.6 year orbit) comet 21P/Giacobini-Zinner. The comet last traveled through the inner solar system in July, 2005, and will next do so in February, 2012.
In the past, there has been a dramatic increase in the meteor shower rate a year before the comet’s return. Numbers as high as 1,000 have been suggested from a dark sky location. More realistically that number could be 200 or so. Unfortunately the peak of activity is predicted to occur during daylight hours for us in the United States on the 8th. And since the peak will be short lived, we may only experience a little enhanced activity once darkness falls. Events like this scenario are difficult to forecast, but anything is possible.
So despite a Waxing Gibbous Moon, I’d highly recommend giving the Draconids an hour or two of your free time. The radiant point in the head of Draco will be high in the northern sky during early evening, so you don’t have to wait until after midnight. (Also, the Moon will be in the opposite side of the sky.) Face north and you’ll see Ursa Major (Big Bear), and the Big Dipper asterism. Draco stretches between Ursa Major and Polaris, the pole star, which is the end star in Ursa Minor (Little Bear), the Little Dipper asterism handle. Draco descends towards the northern horizon to the left of Polaris as the night progresses. It would be best to scan this entire region of sky for Draconids. By morning twilight, Draco’s head will be sitting due north about 20 degrees above the horizon.
The second meteor shower of the month peaks on the night of October 21-22, with the best activity between midnight and dawn’s early light. This major shooting star display is called the Orionids, for the meteors appear to radiate out of the sky just above Orion’s head and not far from his bright red super giant star Betelgeuse, which marks his right shoulder. These remnants of Halley’s Comet intercept the Earth’s orbit nearly head-on at 41.6 miles per second, so they quickly blaze across the sky.
Orion can easily be found. At 3:30 a.m. this giant of a constellation will be due south of your location and about halfway up above the horizon. A thin Waning Crescent Moon will be towards your east and will not affect observing conditions. Therefore, one could expect the typical hourly rate to peak at around 20 or so yellow and green meteors per hour. The Orionids are also noted for producing fireballs that create persistent dust trains high in the atmosphere.
While waiting for “burning rocks” to fall from the sky, you will certainly notice the brightest star in the sky, Sirius, to the lower left and east of Orion. However, there will be an even brighter object noticeable that morning—Jupiter, to the upper right and west of Orion. Now rising before 7:00 p.m., Jupiter is observable at a more decent hour during the early evening. (I will provide a brief Jupiter observing guide in a future column.)
If you wish to observe astronomical bodies like the planets, which are quite a bit more distant than meteors, the local Rhode Island observatories are open on a regular schedule for you to enjoy the view of the heavens through some fine telescopes. Seagrave Memorial Observatory in North Scituate is open to the public every clear Saturday night. Also, Ladd Observatory in Providence is open every clear Tuesday night. Frosty Drew Observatory in Charlestown is open every clear Friday night year round. Be sure to check all the websites for the public night schedules and opening times before visiting these facilities.
Keep your eyes to the skies.
David A. Huestis