By David A. Huestis
I hope many of you had the good fortune of watching the Perseid meteor shower on the peak night of August 11-12. Just prior to the event some astronomers were predicting a brief but substantial increase in activity. Unfortunately that scenario never manifested itself here. I counted 23 Perseids between 1:10 a.m. and 2:50 a.m. Clouds finally blotted out the stars at that end time. Many of the meteors swept through Pegasus, while others streaked down the Milky Way. Some of the brighter shower members left trains of dust that lasted for one to two seconds, making for a decent display of shooting stars this year.
If you happen to travel in a westerly direction after sunset during the next several months, that very bright heavenly beacon you see in the sky will be Venus. This planet, named for the goddess of love, and Earth will be moving closer together as the pair revolves around the Sun in their respective orbits. Through a telescope the image size of Venus will dramatically increase, yet at the same time, the illuminated phase (Venus goes through phases similar to that of the Moon) will decrease. It is best to telescopically observe Venus in a twilight sky so its brilliance does not overwhelm the view in the eyepiece.
If the Perseids didn’t satisfy your appetite for watching “burning rocks” fall from the sky, then mark your calendar for the night of October 7-8 to watch the minor meteor shower called the Draconids. Though this shooting star display only produces ten or less yellowish slow moving meteors per hour, a waxing crescent Moon (First Quarter on the 9th) will set around 10:30 p.m. and will slightly interfere with observing as many meteors as possible. This shower of particles is debris shed by periodic Comet 21 P/ Giacobini-Zinner.
All you have to do to observe as many meteors as possible is to gaze northwards and find Ursa Major (Big Bear), the Big Dipper asterism. At the midnight hour Ursa Minor (Little Bear), the Little Dipper asterism, will be above Ursa Major. The radiant point, in the head of the dragon, will be to the left of the Little Dipper. While the meteors will emanate from this region of the sky, scan east and west up to zenith (directly overhead). These particles are fairly slow moving, hitting our atmosphere at only 12.5 miles per second. As the night progresses watch the northern sky rotate around Polaris, the Earth’s pole star located at the end of the Little Dipper handle.
If you love to observe astronomical events during the quiet time after midnight, then set aside a little more than an hour during the early morning of October 19 to experience once again an occultation of the bright star Aldebaran in the constellation Taurus’ Hyades star cluster. As the waning gibbous Moon moves eastward in our sky, it will pass in front of Aldebaran along the Moon’s bright limb (left edge) at approximately 1:49 a.m. EDT, and will reappear along the Moon’s dark limb (right edge) at approximately 2:53 a.m. EDT. You may see dimmer stars covered and/or uncovered during this time as well, and earlier in the evening on the 18th the Moon will pass in front of other stars in the Hyades cluster too. You will not need a telescope to watch Aldebaran disappear and reappear, although binoculars will enhance the view. With a telescope you might see the star blink as it passes behind crater walls or lunar mountains. Give it a try.
And finally, on the night of October 20-21, the peak of the Orionid meteor shower occurs when the Earth passes through the remnants of Halley’s Comet. Generally a decent meteor shower, an interfering waning gibbous Moon (last quarter on the 23rd) will rise locally on the 20th around 10:00 p.m. in the feet of Gemini the twins. This placement is very close to the shower’s radiant point in the constellation of Orion, not far from the bright red super giant star Betelgeuse. This scenario will most certainly affect observing the peak rate of about 20 or so yellow and green meteors per hour between midnight and dawn’s early light. The Orionid meteors disintegrate in our atmosphere around 41.6 miles per second, and they are also noted for producing fireballs that create persistent dust trains as they blaze across the sky.
While Orion is an easy star pattern to identify, at 3:00 a.m. this giant constellation can be found high in the southeast sky. See accompanying star map.
In conclusion, please remember that the local observatories are open for your viewing pleasure. Visit their respective websites for public observing schedules. Seagrave Memorial Observatory (http://www.theskyscrapers.org) in North Scituate is open every clear Saturday night. (Note: Seagrave will be closed on October 1 due to our annual AstroAssembly convention, and we will also be closed on October 29 for a special member’s only night). Ladd Observatory (http://www.brown.edu/Departments/Physics/Ladd/) in Providence is open every Tuesday night. The Margaret M. Jacoby Observatory at the CCRI Knight Campus in Warwick (http://www.ccri.edu/physics/observatory.htm) is open every clear Wednesday night. And our good friends down at Frosty Drew Observatory (http://frostydrew.org) in Charlestown open every clear Friday night.
Clear skies for all your observing adventures.
Great American Total Solar Eclipse on August 21, 2017. Countdown: 323 days as of October 1, 2016.