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October 2017 Skies

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October Skies

by Dick Cookman



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

Focus Constellations: Auriga, Perseus, Cassiopeia, Andromeda, Pegasus, Cygnus, Lyra, Aquila, Hercules, Draco, Cepheus, Ursa Minor, Ursa Major, Camelopardalis

Comet Journal

Comet C/2017 O1, which was discovered on 7/19/2017 by the All-Sky Automated Survey for Supernovae (ASASSN), moves through Perseus and into Camelopardalis in October. In September, comet aficionados observed aqua color from glowing carbon-rich gases in the 8th magnitude comet. It is expected to reach 7th magnitude in October and November and reaches perihelion on October 14th. It is closest to Earth on the 18th as it rises above the orbits of Mars and Earth and heads upward and outward to the inner Oort Belt in its 10,000 year circuit of the Sun.

Mars Landers

Opportunity is continuing with limited exploration of "Perseverance Valley” on the western rim of "Endeavor Crater” in "Meridiani Planum". The rover is hopping between energy-favorable "lily pads" which are tilted to the north to maximize low levels of solar illumination on the solar panels. Activity is constrained by the need for recharging batteries with the solar panels. At each location, Opportunity is conducting and extensive stereo survey in order to produce a complete digital elevation model that will be utilized to determine answers to questions about the valley’s formation and development. Perseverance Valley may be an ancient spillway carved by water cascading from the rim to the crater floor. The rover observed copious evidence for water along the rim of the crater during the last year as alteration of ancient rock by fluid borne substances and fractures filled with minerals precipitated from aqueous solutions.

As of Sol 4854 (Sept. 19, 2017), the rover remained at a total travel on Mars of 27.97 miles (45.02 kilometers). Solar array energy production averaged 283 watt-hours per sol during the month.

Curiosity's two year traverse over 3 billion year old Gale Crater’s floor (a remnant of the alluvial deposits which once filled the crater) required climbing almost 1000 feet before reaching 3 mile high Mt. Sharp in September, 2014. During the ensuing 3 year interval after arrival, the rover ascended another 30 feet up the north flank of the mountain comprised of Murray Formation mudstones. Then in July, 2017, Curiosity reached a ridge informally named Vera Rubin Ridge after the astrophysicist who uncovered first evidence that clusters of galaxies were organized into superclusters of galaxies. After resuming study of galactic rotation initiated in graduate school, she developed evidence that galaxies had far greater gravitational force than previously realized –– the first evidence for the “dark matter” which is now thought to comprise over 25% of the universe.

In early September, 2017, the rover embarked on a climb to reach the top of the ridge which is the edge of a hematite-containing layer supporting an overlying layer with abundant clay minerals identified from orbit. The ridge is one of the four unique terrains on lower Mt. Sharp recognized before the Science Laboratory landed in 98 mile wide Gale Crater 5 years ago. After approaching the ridge in August, the rover started reconnaissance by skirting along the base of the 213 foot high cliff before finding an embayment with a more gentle slope which it could ascend. The ascent, which started on the 1st and was completed by the 13th, revealed purple and tan rock layers, sedimentary structures, and cross cutting veins of calcium sulfate which collectively will be studied to determine the nature of the depositional and post depositional environments of the horizontally bedded hematite layer in detail. The summit of Vera Rubin Ridge revealed an abundance of rock outcrops and rock pavements exhibiting a variety of colors and textures and relatively steep slopes with a sequence of stepped layers to the south-southwest which the rover reached at the end of September.

Meteor Showers

October’s Meteor Showers include the Draconids which peak at about 5 meteors per hour in dark skies on the 8th, the Epsilon Gemini's which peak on October 18th, and the Orionids which peak on the 21st.

The Draconid shower typically provides a few meteors per hour in dark skies but occasionally storms at 100’s or even 1000’s per hour. Comet 21P Giacobini-Zinner provided the stream of debris that produces the shower. Glare from the waning gibbous Moon is the main detraction.

Lunar glare is less of an issue with the Epsilon Geminids and the Orionids which occur near New Moon. The former is limited to 1 - 2 meteors per hour and the latter, which is derived from Comet Halley’s debris, produces many more, ranging from 20 to 70 meteors per hour during the last 40 years.

Planet Plotting

Morning planets include Venus (-3.8) and Mars (+1.8) in Leo and Virgo, Jupiter (-1.5) in Virgo. Mercury (-1.3 to -0.4) is inn Virgo prior to Superior Conjunction on October 8th after which it dims as it moves into Libra in the evening skies. It passes within a degree of Jupiter on the 18th when both are deep in the glow of sunset. The waxing crescent Moon passes Mercury and Jupiter on the 20th, and Jupiter will be lost from sight as it approaches conjunction with the Sun on October 26th. Venus rises in the wee hours and is well above the eastern horizon at sunrise. Venus and Mars are in close proximity during October and are less than a degree apart on the 5th. The waning crescent Moon passes nearby after the middle of the month.

Saturn (+0.5) in Ophiuchus rises during the day and sets in the evening. The waxing crescent Moon passes Saturn on the 24th. Uranus (+5.7) is in Pisces, and Neptune (+7.8 to +7.9) is in Aquarius. Uranus and Neptune rise in the early evening and set during the predawn hours. Uranus is near the waning gibbous Moon in early October and reaches opposition on the 19th. The waxing gibbous Moon passes Neptune on the 3rd and again on the 30th.


PlanetConstellation(s)MagnitudePlanet PassagesTimeDate
SunVirgo-26.8New Moon3:12PM EDT10/19
MercuryVirgo, Libra-1.3 to -0.4Superior Conjunction
Jupiter 0.93° NNE
5:00PM EDT
4:00AM EDT
VenusLeo, Virgo-3.8Mars 0.21° SSW1:00PM EDT10/5
MarsLeo, Virgo+1.8Venus 0.21° NNE1:00PM EDT10/5
JupiterVirgo-1.5Mercury 0.93° SSW
Solar Conjunction
4:00AM EDT
2:00PM EDT
UranusPisces+5.7Opposition1:00PM EDT10/19
NeptuneAquarius+7.8 to +7.9   


October Moon

October’s New Moon is on the 19th at 3:12PM EDT. It is the beginning of Lunation 1173 which ends 29.57 days later with the New Moon of Nov. 18th at 6:42AM EST.

The Full Moon of October in Aquarius occurs at 2:41PM EDT on the 5th. It is the first full moon following the equinox which some define as the Harvest Moon. This year, September’s Full Moon was considered to be the Harvest Moon by those who define it as the full moon closest to the equinox. The October Moon is also known as the “Blood Moon or Sanguine Moon”. The Celts and the Colonial Americans called it the “Hunter’s Moon”. Chinese refer to it as “Kindly Moon” and it was the “Blood Moon” in Medieval England. Anishinaabe (Odawa and Ojibwe) people in northern Michigan recognize it as “Binaakwe-giizis (Falling Leaves Moon).

Lunar Perigee (closest to Earth) is 227,954 miles or 57.52 Earth radii on the 9th at 1:53AM EDT. Apogee (maximum orbital distance) occurs on the 24th at 10PM EDT when it is at 251,749 miles (63.52 Earth radii).


PlanetConstellationMagnitudeMoon PassageMoon PhaseMoon Age
SunVirgo-26.83:12PM EDT, 10/19New0 days
MercuryVirgo-0.75.0°NNE, 7:00AM EDT, 10/20Waxing Crescent0.66 days
VenusVirgo-3.81.9°NNE, 10:00 PM EDT, 10/17Waning Crescent27.85 days
MarsVirgo+1.81.7°NNE, 7:00AM EDT, 10/17Waning Crescent27.23 days
JupiterVirgo-1.53.7°NNE, 1:00AM EDT, 10/20Waxing Crescent0.41 days
SaturnOphiuchus+0.53.2°N, 8:00AM EDT, 10/24Waxing Crescent4.70 days
UranusPisces+5.74.0°SSE, 3:00PM EDT, 10/6Waning Gibbous16.56 days
NeptuneAquarius+7.80.71°SSE, 9:00AM EDT, 10/3Waxing Gibbous13.31 days
NeptuneAquarius+7.80.84°SSE, 5:00PM EDT, 10/30Waxing Gibbous11.08 days

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