A common yet striking event is the monthly pairing of Venus and the crescent moon. In the closing 10 weeks of Venus’ current evening apparition, pairings will occur at dusk on Nov. 6, Dec. 5, and Jan. 1 and 2.
Jupiter is usually the planet next in terms of brilliance after Venus, so its pairings near the moon, occurring at intervals of 27 to 28 days, are often impressive. The moon is always in its crescent phase when it is seen near Venus, but can appear in any phase, from a thin crescent to full, when it passes Jupiter. This month, Jupiter will appear near the moon on the night of Nov. 21-22, from four hours after sunset until dawn.
Venus appears at greatest elongation, appearing a maximum of 47 degrees from the sun in our sky on Oct. 31, in the afternoon and evening sky, and on March 22, 2014, in the morning. Through a telescope near those dates, Venus appears as a tiny “half moon.” The 20 weeks from the end of October to late March will be an exciting time to follow Venus through telescopes and binoculars, as the backlit planet swings close to Earth and displays all its crescent phases—in the daytime as well as at dusk or dawn.
On our evening twilight chart for November 2013 (above), bright objects are plotted for each day when the sun has sunk to 9 degrees below the horizon, at “mid-twilight.” By then, Venus and about a half-dozen stars of first magnitude or brighter, including the summer triangle of Vega, Altair and Deneb high in the western sky, are easily seen. In November, mid-twilight in the Coachella Valley occurs about 40 to 43 minutes after sunset. Planet positions are represented by a separate dot for each date, with positions for each Friday in November (1, 8, 15, 22, 29) represented by a larger dot and labeled. Rotate the chart until the portion of the horizon circle nearest to your target objects is below them, and you’ll see them depicted at the same orientation as they appear in the sky.
Jupiter does not appear on the evening twilight chart. On Nov. 1, it rises within 4 1/2 hours after sunset. Its rising time shifts earlier by about four minutes per day, until at month’s end, it will rise a few minutes before Venus sets.
Jupiter is also present in the morning, as the brightest “star” then visible. In mid-twilight (see the map below), find it very high in the southwest on Nov. 1, moving about halfway from horizon to overhead in west at month’s end. The other morning planet in view for entire month is Mars. In November, find the red planet just over halfway up, drifting through the southeast early in the month, ending in the south-southeast.
Two additional planets join the morning scene as they emerge from the sun’s glare. The November chart depicting the sky in morning mid-twilight illustrates the changing positions of the four morning planets. First, Mercury pulls out from its Nov. 1 inferior conjunction on the near side of the sun to be spotted by Nov. 8. Look low in the east-southeast, to the lower left of Spica. Mercury brightens, rapidly at first, and then more slowly. Next, just after midmonth, Saturn emerges from the far side of the sun to appear to the lower left of Mercury. The two planets form a close pair on Nov. 25 and 26 and switch places as speedy Mercury moves around toward the far side of its orbit. Saturn appears higher each morning because of the Earth’s faster orbital motion.
On Thanksgiving morning, Nov. 28, four planets—Mercury, Saturn, Mars and Jupiter—span 120 degrees across the sky. Later that same day, Comet ISON will pass within 725,000 miles of the sun’s surface and make a sharp turn to the north, or upper left of the predawn sun. Visit www.pa.msu.edu/abrams/isonfor updates on the comet.
Robert C. Victor was a staff astronomer at the Abrams Planetarium at Michigan State University. He is now retired and enjoys providing skywatching opportunities for school children in and around Palm Springs. Robert D. Miller, who provided the twilight charts, did graduate work in planetarium science and later astronomy and computer science at Michigan State University and remains active in research and public outreach in astronomy.