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The Sky This Week, 2017 October 31 - November 7

Fall back after the Hunter's Moon.
HuntersMoon_161016_AR102_01.jpg
The Hunter's Moon, 2016 October 16
imaged from Alexandria, VA by Geoff Chester
with an Explore Scientific AR102 4-inch f/6.5 refractor
and Canon EOS Rebel T2i DSLR.

The Moon brightens the sky for Halloween’s ghosts and goblins, then waxes to Full Moon on November 4th at 1:23 am Eastern Daylight Time. This Full Moon is popularly known as the Hunter’s Moon thanks to nearly the same orbital geometry as last month’s Harvest Moon. The times of successive moonrises around the time of Full Moon differ by about 35 to 40 minutes, adding a little extra light to the twilight hours. In bygone times this allowed hunters to have a little more time to chase game over the stubble of the harvested fields. In Native American skylore this was also known as the Beaver Moon, since this was the time of year when these industrious rodents were busily preparing for the coming of winter. During the week Luna moves through the faint autumnal constellations, ending the week in the middle of the rising stars of winter. On the evening of the 5th, watch the bright star Aldebaran slip behind the Moon at 7:59 pm Eastern Standard Time, shortly after moonrise. The star will reappear from behind Luna’s slender dark limb at 8:53 pm.

Remember to set your clocks back one hour as you turn in for the night on the evening of the 4th. Technically you should perform this annual ritual at 2:00 am on the morning of the 5th, according to U.S. Code. The subject of Daylight Time and clock-changing has long been a bone of contention ever since it was first legislated in 1918. It was initially adopted as a means to promote the tending of "victory gardens" during World War I, a concept which satisfied factory workers who wanted a little extra food on the table. Within year, though, the law was repealed and Daylight Time became a matter for states and local municipalities to decide. During World War II Daylight Time was observed continuously from February 9, 1942 until September 30, 1945, when once again it became a matter of local choice. It wasn’t until 1966 that a Federal statute was once again passed by Congress as the Uniform Standard Time Act. Under these rules Daylight Time began on the last Sunday in April and lasted until the first Sunday in October. Our current system, with Daylight Time in force from the third Sunday in March to the first Sunday in November, is the result of the Energy Policy Act of 2005. Since these rules are specified in the law of the land they are enforced by a civilian agency, so if you don’t like the current system please call the Office of General Counsel at the Department of Transportation. The Time Service Department here at the Naval Observatory is responsible for producing a uniform time scale, Coordinated Universal Time (UTC); we don’t tell people what to do with it! That said, at least we’ll get back the hour that we lost way back in March.

You will still find Saturn lingering in the southwestern sky as evening twilight begins to darken the sky. The ringed planet’s current tenure in the evening sky is rapidly coming to a close. He sets an hour after the end of evening twilight, and by the end of November you’ll be hard-pressed to spot him at all in the twilight glow.

The next bright planet to grace the sky is Mars, but you’ll have to either be a night owl or a very early riser to catch him. He rises shortly before 5:00 am EDT among the stars of Virgo and spends the week drifting between the third-magnitude star Zaniah and second-magnitude Porrima. His ruddy disc is currently a miniscule 4 arcseconds across, but he will become a great telescopic target when he reaches opposition in late July next year.

Brilliant Venus is now rising at the beginning of morning twilight. She hangs low above the eastern horizon as the sky brightens, so you’ll need to have a good eastern exposure to see her. By the end of the year she will be lost in the solar glare and won’t emerge in the evening sky until early 2018.

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