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January 2017 Skies

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January Skies

by Dick Cookman


Highlights: Comet Journal, Martian Landers, Meteor Showers, Planet Plotting, January Moon

Focus Constellations: Auriga, Gemini, Orion, Taurus, Perseus, Cassiopeia, Andromeda, Cepheus, Draco, Ursa Minor, Ursa Major, Lynx, Camelopardalis

Comet Journal

The short period (5.25 years) comet, 45P/Honda-Mrkos-Pajdusakova, is in the morning sky in early January after passing through perihelion on Dec. 31st. It will remain at 6th or 7th magnitude as it circuits through Capricornus and Aquarius in the predawn skies of January. In February it will move westward through the sky to Leo at 7th magnitude.

C/2016 U1 (NEOWISE) moves eastward in predawn skies from Ophiuchus to Sagittarius, increasing from 8th to 6th magnitude until passing through perihelion on the 14th. In late January it will be in the evening sky, moving through Sagittarius and into southern hemisphere skies as it dims significantly.

2P Enke, V2 Johnson, and 41P/Tuttle-Giacobini-Kresak may approach naked eye visibility in March.

Mars Landers

Opportunity completed exploration of Marathon Valley on Endeavor Crater's rim in August. Mission scientists then chose to venture into the crater and conduct further exploration on the inside of the rim as opposed to earlier plans to continue examination of its exterior. In September, the rover exited Marathon Valley through Lewis and Clark Gap and descended into Bitterroot Valley to Spirit Mound, the first waypoint of her new extended mission. October was devoted to observation of the mound after which the rover headed southwest to an ancient water-carved gully.

On Sol 4580 (Dec. 11, 2016), the rover made further progress to the southwest covering over 49 feet (15 meters). Because the rover is driving on slopes tilted away from the Sun, power was constrained and drives were limited in distance. Some sols following the drives have been "recharge" sols, sols with limited rover activity. A drive on Sol 4582 (Dec. 13, 2016), added another 56 feet (17 meters) toward the southwest. And as always, extensive Navigation Camera (Navcam) and Panoramic Camera (Pancam) images were collected following each drive.

Solar array energy production averaged from 370 to 465 watt-hours. Total odometry on Mars is 27.12 miles (43.65 kilometers).

During the last two years, Curiosity examined the Murray Formation rock layers on the flank of Mt. Sharp, Gale Crater's central peak. The layers were formed from sediment in contact with liquid water in the distant past. They may have never extended to the crater's edge. They dip away from the center at angles between 2.5° and 4°, indicating deposition in a large central lake in the crater. Terrain to the south of the crater is lower than the crater floor and Mt. Sharp's peak is higher than the crater rim obviating likelihood of waterlain layers at high elevation. Those layers may have been deposited by morning winds carrying sediment up the mountain's flanks as the Sun warmed the surface.

Alternative explanations suggest that upper layers were waterlain like those of the Murray Formation when the crater was at a much lower elevation. The land near young impact craters is depressed by the impact's force and the area most depressed is at the center. As the planet crust responds with isostatic adjustment over time, the crater and its surroundings rebound and greatest rebound will occur in the crater's center. Initially, the crater may have been depressed so far that it could fill up with water which deposited a sequence of layers filling the crater. Subsequent rebound and erosion would then result in the current situation.

Meteor Showers

The Quadrantid Meteor Shower, a dominant shower in January, is one of the year's best. Peaking on the 3rd, there will be minimal competition with the waxing crescent Moon which sets before 10PM EST. The dark sky may display over 100 meteors per hour emanating out of Quadrants Muralis, an extinct constellation which included part of Bootes. In prime viewing time an hour or so before sunrise twilight, observers facing southwest will see streaking meteors radiating outward from a radiant between the Dippers and Bootes, high in the east-northeast. The source of debris in the shower may be Comet 96/P Machholtz or asteroid 2003 EH1, or both. Uncertainties in orbits and gravitational effects of these bodies thwart precise determination.

The Delta Cancrid Meteor Shower on the 17th, a minor shower with ~5 meteors per hour, faces competition with a waning gibbous Moon. Orbit similarities suggests it is composed of debris from earlier passages of asteroid 2001 YB5.

Planet Plotting

Venus (-4.4 to -4.5) is spectacular in the southwest evening sky providing its best apparition of the past 5 years as it approaches Maximum Eastern Elongation on the 12th when it is 47° from the Sun and 30° above the horizon. It moves from Aquarius to Pisces during the month. Nearby Mars (+0.5 to +0.9), also in Aquarius to Pisces, is higher than Venus in the southwest sky after sunset and Venus closes the distance to the red planet as Mars moves toward Neptune (+7.9) in Aquarius during the month.

On the 1st, 2nd, and 3rd, an amazing sequence of apparitions of Comet 45P/Honda-Mrkos-Pajdusakova, Venus, Mars, Neptune, and the crescent Moon transpire in the western sky after sunset. On the 1st, the comet is above the southwestern horizon in central Capricornus, the crescent Moon is higher, near the easternmost part of the constellation, and Venus is slightly above the Moon. Mars and Neptune are above Venus. On the next evening, the crescent Moon is above Venus with Mars and Neptune higher yet. On the 3rd the Moon will be above Mars & Neptune which are above Venus. Views of the comet and Neptune will require binoculars. On the 1st, Mars & Neptune will appear closer to one another than at any other time in the last 700 years making it much easier to find Neptune which is too dim to see with naked eyes, and on the 12th, Venus will mark the location of nearby Neptune. At the end of January, another show with the same players will feature the waxing crescent Moon passing Neptune, Venus, and Mars in succession after sunset from the 29th through Feb. 1st. Uranus (+5.8) in Pisces is in the southern sky after sunset and sets after midnight.

Mercury (-0.5 to -0.3) in Sagittarius reaches Maximum Western Elongation on the 19th when it is 24° from the Sun and 10° above the southeastern horizon 30 minutes before sunrise. Jupiter (-1.9 to -2.0) rises in Virgo at about 1AM EST. It is highest above the southern horizon just before morning twilight, dominating the predawn sky. Saturn (+0.5) in Ophiuchus rises an hour and a half before the Sun on the 1st, and by the 31st, rises in the southeast 3 hours before the Sun.

PlanetConstellationMagnitudePlanet Passages
SunSagittarius, Capricornus-26.8New Moon, 1/27 7:07PM EST
MercurySagittarius, Ophiuchus+1.3 to -0.3Max. W. Elong. 1/19, 5AM EST
VenusAquarius, Pisces-4.4 to 4.5Max. E. Elong. 1/12, 8AM EST
Neptune, 0.4°S. 1/12, 9PM EST
MarsAquarius, Pisces+0.9 to +1.0Neptune, 0.02°S. 1/1, 2AM EST
JupiterVirgo-1.9 to -2.0 
NeptuneAquarius+7.9Mars, 0.02°N. 1/1, 2AM EST
Venus, 0.4°N. 1/12, 9PM EST

January Moon

The New Moon of January is on the 27th at 7:07PM EST. The New Moon is the beginning of Lunation 1164 which ends 29.72 days later with the New Moon of February 26th at 9:59AM EST.

The Full Moon in January in Taurus occurs at 6:34AM EST on the 12th. The January Moon is called the “Moon after Yule” or "Old Moon". Colonial Americans used the term “Winter Moon”. The Celts called it the “Quiet Moon”, and the Chinese refer to it as the “Holiday Moon”. Medieval English thought of it as the “Wolf Moon”, and the Anishinaabe (Odawa and Ojibwe) people of northern Michigan recognize it as "Gichi-manidoo-giizis" (Great Spirit Moon)“.

Lunar perigee (closest to Earth) is 225,706 miles or 56.95 Earth radii on the 10th at 1:01AM EST. Apogee position in orbit (maximum orbital distance) is at 251,602 miles (63.49 Earth radii) from Earth on the 21st at 7:14PM EST.

Cecil Adams’ reasons why we need the Moon:

“Reason #3: It’s insurance against getting chucked into interstellar space. In the young and restless early years of a solar system, the gravitational force of the larger planets (read: Jupiter and Saturn) may interfere with the orbits of the smaller ones, sometimes flinging them out of the system altogether. Computer simulations suggest that even if this had happened to earth, the warming properties of the moon’s gravitation described above might well have kept temps high enough for water to remain liquid and for life to evolve anyway.

(Incidentally, other simulations have demonstrated that the presence of the earth-moon team is the only thing keeping Mercury where it belongs: without us, its gravitational interaction with Jupiter would drag it into a high-stakes run-in with Venus, which would likely result in Mercury’s getting ejected from orbit and bonking into who knows what along the way. It’s too bad we couldn’t save Pluto too, but of course that was just politics.)”

PlanetConstellationMagnitudeMoon PassageMoon Phase/Age
SunCapricornus-26.87:07PM EST, 1/27New ~ 0 days
MercurySagittarius-0.24.0°N, 8PM EST, 1/25Waning Crescent ~27.75 days
VenusAquarius-4.41.9°N, 4AM EST, 1/2Waxing Crescent ~4.25 days
VenusPisces-4.54.0°S, 10AM EST, 1/31Waxing Crescent ~3.37 days
MarsAquarius+0.90.2°N, 2AM EST, 1/3Waxing Crescent ~ 5.00 days
MarsPisces+1.02.0°S, 8PM EST, 1/31Waxing Crescent ~ 4.04 days
JupiterVirgo-2.03.0°N, Midnight EST, 1/18Waning Gibbous ~19.92 days
SaturnOphiuchus+0.54.0°N, 5AM EST, 1/24Waning Crescent ~ 26.13 days
UranusPisces+5.83.0°S, 9PM EST, 1/5Waxing Crescent ~7.92 days
NeptuneAquarius+7.90.4°N, 11PM EST, 1/2Waxing Crescent ~4.76 days
NeptuneAquarius+7.90.2°N, 6AM EST, 1/30Waxing Crescent ~2.45 days


Maybe this isn't good idea, but my suggest is to rename this topic to "Monthly Sky 2017" and inform our users about objects we can expect every month in 2017.This will become to good tradition for us.

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