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May 2018 Skies

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May Skies

by Dick Cookman


Highlights: Comet Journal, Martian Landers, Planet Plotting, May Moon

Focus Constellations: Leo, Çancer, Gemini, Auriga, Lynx, Camelopardalis, Cassiopeia, Cepheus, Ursa Minor, Draco, Ursa Major, Coma Berenices, Bootes, Corona Borealis, Hercules

Comet Journal

Ninth magnitude comet C/2016 M1 (PanSTARRS) is the only May comet exceeding 10th magnitude, but its extreme southerly position produces unfavorable views this year for northern observers. It is moving southward through Sagittarius and is best observed well after midnight. It will leave northern hemisphere skies in early June, long before its August perihelion.

C/2016 R2 (PanSTARRS) is not as bright at 10th magnitude but is much better positioned in Auriga, passing south of Capella in early May. it reaches perihelion on May 9th then dims as it continues its journey back to its Oort Belt home.

Mars Landers

According to A.J.S. Rayl in his March 5, 2018 Planetary Society blog: “the Spirit and Opportunity Exploration Rovers which landed on Mars in early 2004 have surprised every one, including their human handlers. With their human-like personalities, never-give-up determination, remarkable resilience, and a kind of tenacity defined in these pages as MER metal, the twins endeared themselves to people around the world. Each met all the objectives during their primary missions, and made headlines, sending home science gold in evidence of past water environments on ancient Mars.

Spirit went on to explore the Columbia Hills and its surroundings, making history as the first robot to scale a hill, the first to discover near pure opaline silica, and first to send home evidence of carbonates, signs of water we might drink. After more than six challenging but highly productive years in an unforgiving Gusev Crater, Spirit went into low energy hibernation in March 2010 as the mission’s fourth winter took hold. We never heard from her again.

Opportunity trekked onward and in August 2011 pulled up to the outer western rim of Endeavour Crater and into area called Cape York. She would soon find evidence for ancient clay minerals, known as smectites, and the most ancient Martian ground ever found by a surface mission on Mars. Today, this rover continues to explore the big crater’s rim farther south at Cape Byron, from inside Perseverance Valley, a channel that cuts through the rim segment west to east, from rim to floor. “We have watched Opportunity overcome so many obstacles and do so many things – we’ve watched her wander into and around craters, drive across a sea of ripples and dunes, and we have gotten stuck a number of times and managed to get ourselves out,” said MER Engineering Team Chief Bill Nelson, of the Jet Propulsion Laboratory (JPL), where all of NASA’s Mars rovers were born. “We have watched various astronomical events, like Comet Siding Spring, and imaged the Martian moons, and dust devils moving by,” he continued. “We have watched landers come in and we have watched orbiters arrive. We’ve done a lot of different kinds of things and in the process we have made a number of scientific and engineering discoveries. Through it all, our rover just keeps going and going."

With Sol 5000 coming as it did in the contrails of the 14th anniversary of surface operations and 14th birthday for Opportunity in January, the significance of this Martian measure of mission longevity was generally lost on Earth’s population at large. Still, 5000 sols is – big.”

Curiosity is a relative newcomer on Mars with only 2000 sols logged as of March 22nd during its exploration of Gale Crater. After an almost 3 year southwesterly trek from the landing site to Mt. Sharp, the rover turned to the southeast to start its ascent. It crossed the lower layers of the mountain, climbed over the Murray formation, then ascended Vera Rubin Ridge. On Jan. 29th, Curiosity turned to the northeast and continued exploration of the top of the ridge. After turning eastward on Mar. 15th it arrived at the middle of the strongest spectral detection of hematite identified from orbit on March 28th. After detailed observations were completed, most of April was devoted to examination of a diverse collection of conglomerates, breccias, and other rocks at the top of Vera Rubin Ridge on the flank of the mountain. April 20th marked the conclusion of exploration as Curiosity backtracked westward, descended from the ridge, then turned northward over rocks of the Murray formation. The next destination for the rover is the Red Cliff which is a potential drilling target.

Meteor Showers

The best meteor shower of May is the Eta Aquarids which peak on the 6th during the waning gibbous Moon. Meteor rates average about one per minute in dark skies. The Sun rises before Moonset so glare from the adjacent Moon in Capricornus will interfere during best viewing during the predawn hours when Earth is plunging into the river of debris abandoned by previous passages of Comet Halley.

Planet Plotting

Venus (-3.8 to -3.9 ) is in Taurus and Gemini in May and shines brightly in the early evening western sky. A star-studded pinwheel decorates the evening sky with brilliant Venus in the center surrounded by a circle of bright 1st magnitude stars such as Procyon in Canis Minor, Castor and Pollux in Gemini, Capella in Auriga, Aldebaran in Taurus, and Rigel & Betelgeuse in Orion. On the evening of the 17th, the waxing crescent Moon will appear in close proximity with Venus, and both will set together. After Venus sets in the west, Jupiter (-2.4 to -2.3) rises in Libra in the east. It is at opposition on the 8th when the Sun, Earth, and Jupiter are lined up and Jupiter is at its brightest for 2018. It rises as the Sun sets and sets at sunrise. It will be within 4° of the waxing gibbous Moon in the afternoon of the 27th.

Saturn (+0.3 to +0.2) in Sagittarius rises after midnight, and Mars (-0.4 to -1.4) in Capricornus and Sagittarius follows an hour later. Both are visible in the southeast before dawn. Mars appears to double in brightness and nearly doubles in size in May as it approaches opposition in July. The waning gibbous Moon appears to approach Saturn before dawn on the 4th and the 31st, and will be closest during the following afternoons. The Moon will be in close proximity to Mars before dawn on the 6th. Neptune (7.9) rises just before dawn in early May in Aquarius and about 2AM EDT on the 31st. It may be found low in the southeast before dawn in May and is within 2° of the waning crescent Moon on the 10th. Uranus (+5.9) in Aries appears low in the eastern sky before dawn and Mercury (+0.4 to -1.6) in Pisces, Aries, and Taurus is immersed in the glow of dawn. On the 13th, the narrow waning crescent Moon approaches Uranus and Mercury before dawn and is closest at midday.

PlanetConstellation(s)MagnitudePlanet PassagesTime, Date
SunAries, Taurus-26.8New Moon7:48AM EDT, 5/15
MercuryPisces, Aries, Taurus+0.4 to -1.6Uranus, 2.0°N5:00PM EDT, 5/12
VenusTaurus, Gemini-3.8 to -3.9  
MarsSagittarius, Capricornus-0.4 to -1.2  
JupiterLibra-2.4 to -2.3Opposition9:00PM EDT, 5/8
SaturnSagittarius+0.3 to +0.2  
UranusAries+5.9Mercury, 2.0°S5:00PM EDT, 5/12

May Moon

The New Moon of May on the 15th at 7:48AM EDT is the beginning of Lunation 1180 which ends 29.30 days later with June’s New Moon on the 13th at 3:43PM EDT. The Full Moon on the 29th at 10:20AM EDT is known as the “Planting or Flower Moon” and the “Milk Moon.” Celts called it “Bright Moon,” and Colonial Americans called it “Milk Moon.” Chinese refer to it as “Dragon Moon,” and it was the “Hare Moon” in Medieval England. Anishinaabe (Odawa and Ojibwe people) recognize it as “Zaagibagaa-giizis” (Budding Moon.)

Lunar Apogee (maximum orbital distance) occurs on the 5th at 8:35 PM EDT when the Moon is at 251,318 miles (63.41Earth radii). Perigee (closest to Earth) is 226,040 miles or 57.04 Earth radii on the 17th at 5:05PM EDT.

PlanetConstellationMagnitudeMoon PassageMoon PhaseMoon Age
SunTaurus-26.87:48AM EDT 5/15New0 days
MercuryPisces-0.12.0°S, 1:00PM EDT, 5/13Waning Crescent27.63 days
VenusTaurus-3.85.0°S, 2:00PM EDT, 5/17Waxing Crescent1.71 days
MarsSagittarius-0.53.0°N, 3:00AM EDT, 5/6Waning Gibbous20.21 days
JupiterLibra-2.34.0°N, 2:00PM EDT, 5/27Waxing Gibbous12.26 days
SaturnSagittarius+0.31.7°N, 4:00PM EDT, 5/4Waning Gibbous18.75 days
SaturnSagittarius+0.21.6°N, 9:00PM EDT, 5/31Waning Gibbous15.38 days
UranusAries+5.95.0°S, 11:00AM EDT, 5/13Waning Crescent27.54 days
NeptuneAquarius+7.92.0°S, 5:00AM EDT, 5/10Waning Crescent24.29 days

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