The Sky This Week, 2016 October 11 - 18
Launch of TacSat-2 from NASA Wallops Flight Facility
imaged 2006 December 16 from Alexandria, VA
The plume of the Minotaur rocket hangs in the dawn sky with the waning crescent Moon.
The Moon brightens the overnight hours this week, washing out the dim autumnal constellations before ending the week among the rising stars of winter. Full Moon occurs on the 16th at 12:23 am Eastern Daylight Time. October’s Full Moon is popularly known as the Hunter’s Moon. The geometry of the Moon’s path in the sky is similar to last month’s Harvest Moon, so the interval between successive moonrises around the time of Full Moon causes Luna to appear to rise at nearly the same time for a few nights. In September this phenomena was used by farmers to use the light of the rising Moon to help them bring in more crops. This month hunters have a bit of extra light to pursue game across the stubble of the harvested fields. The Moon travels through a very sparsely populated area of the sky this week, so she won’t pass any bright objects until the night of the 18th, when she cozies up to the bright star Aldebaran. In the DC are you can watch Aldebaran disappear behind Luna’s bright limb at 1:37 am EDT on the morning of the 19th. It will reappear from behind the Moon’s dark limb just over an hour later.
This weekend those of us who live in the Washington area will have the opportunity to see a rocket launch to the International Space Station. Currently scheduled for the evening of the 17th at 7:40pm EDT, an Orbital Sciences Antares rocket will propel the OA-5 Commercial Resupply Mission to a rendezvous with the Space Station, which will pass about 250 miles overhead. Anyone with a clear view to the southwestern sky in the DC metropolitan area and much of the mid-Atlantic should have a good view if the weather is clear. The launch will take place at NASA’s Wallops Flight Facility on the Virginia portion of the DelMarVa peninsula. The Antares is a two-stage rocket which uses a liquid-fueled booster stage and a solid-propellant upper stage. The first stage engines develop 830,000 pounds of thrust and should leave a bright trail of flame as the rocket climbs higher. The first stage shuts down after four minutes, then the rocket coasts for about a minute and a half. The second stage ignites at T-plus 5:40 and burns for two minutes. It should look like a bright orange star embedded in a surrounding diffuse plume. Eight minutes after launch the Cygnus re-supply craft should be in orbit, beginning its chase of the Space Station. It should dock with the ISS on the morning of the 17th. For further updates visit the NASA Wallops Flight Facility website at http://www.nasa.gov/mission_pages/station/structure/launch/orbital.html.
Venus continues to become more prominent in the evening twilight sky. She is now moving rapidly toward the stars in the "head" of Scorpius and will pass close to the bright star Dschubba early next week. She is also closing in on Saturn, which she’ll pass at the end of the month.
Saturn struggles to keep ahead of the Sun, but his slow eastward crawl is rapidly losing ground to the day-star. You can still get a glimpse of him in the telescope during the twilight hour, but by the time the sky gets truly dark he’ll be wallowing in the turbulence above the horizon.
Unlike Saturn, Mars has the "legs" to keep pace with the advancing Sun. This week he continues his journey through the stars of Sagittarius, passing just over a degree north of the star Nunki, second-brightest star in the constellation, on the evening of the 15th.
Just before dawn look low in the east for the return of Jupiter. You’ll find him about five degrees above the eastern horizon about half an hour before sunrise. He will grace our evening skies next spring, but in another couple of months many of us will be getting up early to enjoy a view of him in our telescopes in the undisturbed morning air.