Eli on Earth: Celestial Highlights for October and early November 2015

Illustrations from Sky Calendar are provided by Abrams Planetarium. Morning and evening twilight sky maps by Robert D. Miller.

During October and early November, there are exceptionally beautiful gatherings of planets in the morning sky. A waning crescent Moon graces the lineup of planets on Oct. 8-11 and Nov. 6-7. Except as noted, these spectacular sights through Nov. 10 will be well seen about an hour before sunrise.

We hope you will join family and friends to view the beautiful lineup of planets in the morning sky. What a great way to start the day! With daylight saving time still in effect through October, a brief session from 1-1/4 hours to one hour before sunrise is not unreasonably early by the clock. It will be well worth getting out then to enjoy the planetary gatherings. The displays on Oct. 8-11, Oct. 16-18, Oct. 22-29, and Nov. 6-7 will be especially noteworthy.

The two brightest “stars” in the current morning sky are actually planets. An hour before sunup they appear in the eastern to east-southeastern sky: Venus, with Jupiter close by, though not as bright. Next in brightness after Jupiter is blue-white twinkling Sirius, the “Dog Star” in the southern sky. To confirm, look to the right or upper right of Sirius for Orion the Hunter, with his 3-star belt pointing directly at Sirius. Return to Venus and Jupiter in the east and look for a less bright object of contrasting color nearby: it is the reddish Mars, between the two bright planets through Oct. 15, very close to Jupiter Oct. 16-18, to the two planets’ lower left Oct. 19-31, very close to Venus Nov. 1-5, and between the two bright planets again, onward from Nov. 6. Keep your eyes on the eastern morning sky in coming weeks for some spectacular changes. Here is a selection of the best events.

Thurs. Oct. 8, one hour before sunrise: Venus gleams brilliantly within 4° to the lower left of the crescent Moon. Jupiter shines 13° lower left of Venus. Faint reddish Mars glows 4° above Jupiter and 9° lower left of Venus. Mercury, just beginning a morning apparition, rises in east within 19° lower left of Jupiter. Mercury brightens rapidly and climbs higher in coming days, but not high enough to meet any of the other planets. This morning and next, note the blue-white star Regulus, heart of Leo, about 2.5° north (upper left) of Venus. This morning, follow the Moon and Venus until sunrise and well beyond to catch Venus in the daytime. A telescope and even a steadily held pair of binoculars will reveal Venus as a crescent. Look an hour before sunup each of the next three mornings and follow the Moon as it slides down the lineup of four planets.

Fri. Oct. 9: The Moon appears lower and closer to the Sun this morning, so today’s crescent is thinner than yesterday’s. Brilliant Venus is now within 8° to the Moon’s upper right. Bright Jupiter is about 5.5° lower left of the Moon. Faint Mars appears less than 4° upper right of Jupiter and about the same distance north (upper left) of the lunar crescent. Can you spot Mercury very low in east?

Sat. Oct. 10: The old Moon, just 2.5 days before New, is a striking sight with the sunlit crescent cradling the earth-illuminated darker side within its horns. Look for Mercury 11° lower left of Moon, and Jupiter within 8° above the Moon. Higher yet, in order: dim red Mars, brilliant Venus, and Regulus to Venus’ upper left.

Sun. Oct. 11: Last chance to see the thin crescent Moon in the morning sky, ending this cycle of phases. Just 37 hours before New, it’s a few degrees above the horizon and a few degrees south of due east. Mercury is just over 1° upper left of the Moon’ northern cusp (upper point of the crescent), 29° lower left of brilliant Venus and 18° lower left of Jupiter. Faint Mars is 2.8° above Jupiter, while Regulus is 3.1° to the upper left of Venus. This week, watch Mars close in on Jupiter, while Venus widens its distance from Regulus. Mercury climbs to its highest in the morning sky for this year late this week, but gets no closer than 28° to the lower left of Venus.

A brief switch to evening: On Thurs. Oct. 15, one hour after sunset, look low in SW to WSW to find the 3-day old waxing crescent Moon with Saturn 8° to its upper left. Look also for reddish twinkling Antares, heart of the Scorpion, 10° lower left of Saturn. By Friday at dusk, the Moon appears 5° upper left of Saturn.

Sat. Oct. 17, one hour before sunrise: Look closely for faint Mars just 0.4° (less than a Moon’s width) to the north (upper left) of Jupiter.

Oct. 22-29: Three planets, in order of brightness Venus, Jupiter, and Mars, form a trio, appearing within a 5-degree field of view. Binoculars magnifying up to about 10-power will fit the trio in on these eight mornings. Binoculars of lower magnification, such as 7X, will fit them in for a longer interval, Oct. 17-Nov. 2 if they provide a 7-degree field. Most trios of naked-eye planets involve Mercury (always low in twilight) or Venus (usually low), but on this occasion we catch Venus at its greatest apparent distance from the Sun and near peak altitude of a very favorable apparition high in the eastern morning sky.

Sun. Oct. 25 and Mon. Oct. 26: Venus and Jupiter will appear just over a degree apart, providing striking views, all within a single telescope field: Jupiter with its four bright moons discovered by Galileo, and Venus appearing as a "half moon". This sight should not be missed! The next pairings of Venus-Jupiter, at dusk on August 27, 2016 and at dawn on November 13, 2017, will be tighter, but low in twilight and will catch Venus on the far side of its orbit, displaying a tiny, nearly full disk. We must wait until the year 2036 for the next pairings of Jupiter with Venus in half or crescent phase, and until Nov. 2039 for a pairing of these planets within the same telescopic field while high in a dark sky.

Beginning Tues. Oct. 27, in morning twilight: Follow the Moon daily for 15 mornings, as it wanes from Full low in the west on Oct. 27, to a thin, old crescent low in ESE only 30 hours before New on Tues. Nov. 10. Watch also for these events:

Thurs. and Fri., Oct. 29 and 30, one hour before sunrise: Watch the waning gibbous Moon leapfrog past Aldebaran, eye of Taurus, the Bull. (Moon will appear widely S (lower left) of Pollux on Nov. 2, and 7° from Regulus on Nov. 4 and 5.) On Oct. 29 and 30, 45 min. before sunrise, Mercury passes within 4° N of emerging Spica. Use binoculars to see this star to the lower right of Mercury. Each morning, Spica appears higher in the sky (resulting from Earth’s revolution around the Sun), and Mercury lower (because the inner planet is faster than Earth and circling around to the far side of the Sun).

Tues. Nov. 3: Venus passes Mars in the last of three close predawn pairings of planets in October-November 2015. Look for the faint red planet just 0.7° N (upper left) of brilliant Venus. This morning the Moon is at Last Quarter phase, appearing half full and 90° or one-quarter circle west of the Sun.

Fri. Nov. 6: Jupiter within 3° N (upper left) of Moon. Venus 11° to Moon’s lower left. Mars 1.6° upper right of Venus.

Sat. Nov. 7: Venus 1.6°, Mars 2.8°, to upper left of Moon. Venus-Mars 2.0° apart.

Mon. Nov. 9: Spica within 4° S (lower right) of Moon.

And finally, on Tues. Nov. 10, about 45 minutes before sunrise: Look for a thin, old crescent Moon, about 30 hours before New, rising in E to ESE 11° lower left of Spica.

Looking ahead: In mid-December 2015, Saturn will emerge into the morning sky. When Mercury returns from late January through most of February 2016, all five naked-eye planets will be fine display in a long arc from ESE to W across the southern morning sky. Stay tuned!

Resources:

For illustrations of most of the events listed above, stop by the Abrams Planetarium to pick up a copy of the October Sky Calendar. To subscribe to Sky Calendar, visit www.abramsplanetarium.org/skycalendar/

We are including Robert Miller’s twilight charts depicting only the brighter stars and planets at morning and evening mid-twilight, about 45 minutes before sunrise and 45 minutes after sunset in October 2015. Miller’s charts depicting positions of bright planets and first-magnitude stars at mid-twilight for future months will eventually appear at www.abramsplanetarium.org/msta/

Robert C. Victor was Staff Astronomer at Abrams Planetarium, Michigan State University. He is now retired and enjoys providing skywatching opportunities for school children and the general public.

Robert D. Miller, who provided the twilight charts and the planet orbit 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.