If you're south of the equator, Mercury puts on a nice show during the first two weeks of this month, but for us northerners it's a difficult-to-near impossible task to see it as it will be setting deep in the bright evening twilight within an hour of sunset. Saturn is still in evidence, low in the southwest for a few hours after sunset. Mars is the most well-placed of all the planets, shining almost due south at nightfall. But since it continues to recede from Earth, it continues to fade. In fact, it loses almost half its brilliance during November. Finally there is Venus, the lone morning planet, which literally vaults into prominence from being buried in sunrise fires at the start of the month, to climbing well up into east-southeast sky before the break of dawn by month's end. [The Night Sky This Month: November 2018 Sky Maps]
In our schedule, remember that when measuring the angular separation between two celestial objects, your clenched fist held at arm's length measures roughly 10-degrees. Here, we present a schedule below which provides some of the best planet viewing times as well directing you as to where to look to see them.
Mercury – is dismally low for skywatchers at mid-northern latitudes (but marvelously high for those at mid-southern latitudes like Cape Town and Auckland!). It reaches greatest elongation (23 degrees) on Nov. 6, this year's least favorable evening apparition. Well south of the sun, the zero-magnitude planet sets only an hour after it. On Nov. 27, Mercury passes inferior conjunction, eventually becoming well-placed in December's morning sky.
Venus – is a good reason to be up at the crack of dawn in November; it's a silvery lamp that rises above the east-southeast horizon. Venus was at inferior conjunction on Oct. 26. But the steep angle of the ecliptic at dawn in late autumn helps Venus vault noticeably higher with each passing day for observers at mid-northern latitudes.
You might first glimpse Venus on the morning of Nov. 1, rising only about 35 minutes before the sun. But just a few days later on Nov. 4, viewers around 40 degrees north latitude can see Venus come up a full hour before the sun and shine more than 10 degrees above the horizon at sunrise.
As November ends, Venus rises more than three hours before the sun and hangs 30 degrees up at sunrise. All month Venus brightens impressively and in early December it will reach the pinnacle of its magnificent brightness, shining at magnitude -4.9. Through a telescope, the phase of the planet looks most remarkable early in the month. That's when you may be able to glimpse Venus when it's only a few percent illuminated, a hairline crescent close to an arcminute long; about 1/30 the apparent diameter of the moon.
Venus is not alone in the dawn sky. Its leap takes it up into the proximity of the bluish 1st-magnitude star Spica in Virgo. Venus rises under Spica all month and at first seems destined to soar up and catch it. Instead, the closest it gets to Spica is 1.2 degrees early on the morning of the 15th.
Mars – still glows orange in the southern sky after sunset and sets just prior to midnight. On the 1st, while 74 million miles from the Earth, Mars shines at magnitude -0.6. As the distance increases to 94 million miles by the end of November, the planet fades to magnitude 0.0 and its telescopic disk will have shrunk by 21 percent. Since it is summer in the Martian southern hemisphere, the south polar cap, tilted 23 degrees toward the Earth, has finally disappeared. In November Mars will show a greater phase defect than at any other time this year, its disk being only 86-percent illuminated. Looking due south as darkness falls on Nov. 15th, you'll see Mars shining about 4 degrees to the upper left of the moon.
Jupiter – might be visible in the early evening sky of Nov. 1 with binoculars; scan low near the southwest horizon about a half hour after sunset for perhaps your final glimpse of the biggest planet of the solar system before it completely disappears from view into the sunset glow. About 7 degrees to its left is the solar system's smallest planet, Mercury, shining only about ¼ as bright. On Nov. 26, Jupiter is in conjunction with sun and transitions from the evening to the morning sky.
Saturn – appears about half as bright as Mars this month, but it remains one of the leading lights of the western twilight sky nonetheless. Saturn is that bright yellowish-white "star" situated 4 degrees to the lower right of 4-day old crescent moon in the south-southwest evening sky of Nov. 11th. The ringed planet will disappear into the sunset before Christmas.
Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications, and he is also an on-camera meteorologist for Verizon FiOS1 News in New York's Lower Hudson Valley.
