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May Skies


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May Skies

by Dick Cookman

05/5/2014

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

Focus Constellations: Cassiopeia, Camelopardalis, Lynx, Ursa Major, Ursa Minor, Cepheus, Draco, Lyra, Hercules, Corona Borealis, Bootes, Canes Venetici, Coma Berenices, Virgo, Leo

Comet Journal

C/2014 E2 (Jacques) was discovered on March 13, 2014 and rapidly ascended to 8th magnitude as it moved parallel to the Milky Way and into northern hemisphere skies in April. It is currently in Monoceras and will move toward Orion in May, possibly reaching naked eye visibility by the end of the month when, right after sunset, it will be near the horizon in the west - northwest. As it approaches perihelion on July 2nd, Comet Jacques will reach maximum brightness (+4.0?). It will then rise above the plane of the Solar System and pass about 8,000,000 miles from Venus on the 13th. It may still be visible to the naked eye at magnitude 5 - 6 when closest to Earth on August 28th (52,000,000 mi).

Comet C/2012 X1 (LINEAR) and Comet C/2012 K1 (PanSTARRS) are both at 8th magnitude and will remain that bright until July. PanSTARRS is moving through Ursa Major below the handle and cup of the Big Dipper in May and is visible throughout the night. It reaches perihelion on the other side of the Sun on August 27th and may reach 6th magnitude when closest to and below Earth in southern hemisphere skies in November. LINEAR is moving into southern hemisphere skies in May and is an early morning apparition as it moves southwesterly along a path between Aquarius and Capricornus. It will be nearest to Earth on June 27th in Pisces Austrinus and not visible from northern latitudes.

Mars Landers

Opportunity is near Solander Point on the rim of Endeavor Crater. It is on the crest of the highest hill encountered during the mission's ten years on Mars. The hill is part of Murray Ridge rising southward from Solander Point as a ridge forming an elevated portion of the western rim of the 14 mile (22 kilometer) diameter crater.

From Sol 3609 (March 19, 2014) to Sol 3635 (April 15, 2014) the rover traveled almost 500 feet southwestward along the ridge in order to approach a local ridge top, a vantage point offering a view with an entire sweep of Endeavour Crater. The vantage point provides an opportunity to collect a spectacular color panorama of Endeavour. On Sol 3623 (April 3, 2014), the rover moved about 52 feet (16 meters) in a clockwise arc around some obstacles in an approach to a large rock outcrop. Moving closer to the outcrop would be difficult, so it was decided to document the outcrop with imagery and then back away and continue to the local ridge top. After completing the panoramic photo shoot, Opportunity traveled another 650 feet in order to approach an area of clay minerals imaged from orbit but experienced elevated motor currents in the right-front wheel. Since heating of the actuator did not resolve the issue, the rover switched to driving backwards, reducing the current demand.

Solar array energy production rose about 14% during the interval to 658 watt-hours per day.

On April 2nd, NASA’s Curiosity Mars rover drove the final 98 feet feet (30 meters) on its trip to “the Kimberley,” a planned destination observed from orbit in early 2013. It has four different intersecting rock types in an area which may be ideal for studying rock clues about ancient environments that may have been favorable for life.

The mission’s investigations at the Kimberley are planned as the most extensive since Curiosity spent the first half of 2013 in an area called Yellowknife Bay where drilling produced samples of the underlying mudstones which were then subjected to detailed chemical and textural analyses. The Kimberley is characterized by a tilted sequence of sandstone layers exhibiting differential erosion where some of the exposed edges of the layers on the ground surface are eroded more deeply than others creating a series of parallel ridges and valleys.

Rock layers can be differentially eroded due to the nature of the cementing materials between the sand grains. Some cements are hard, resisting erosion and causing ridge formation, others are soft allowing deeper erosion of the layers which produces small valleys. The nature of these cements reveals the different types of wet environmental conditions and processes active in the lithification (rock formation) of the preexisting sediments from which the rock layers were formed. Quartz cement between quartz sand grains produces much harder rock that that produced by calcite (carbonate) cement or by cements comprised of silt or clay. Erosion resistant sandstone forms a capping layer of mesas and buttes. The sandstones could even hold hints about why Gale Crater has a large layered mountain, Mount Sharp, at its center.

By the end of April, preliminary drilling sites were selected. Preparatory activity produced a hole about 0.8 inch (2 centimeters) deep in the target called “Windjana.” The rover team plans to decide whether to proceed with deeper drilling of this rock in coming days.

Meteor Showers

Another dagger in the heart of the Aristotelian view that the heavens are perfect and unchanging may be evident in May with a new meteor shower (storm) emanating from celestial north before dawn on the 24th. According to Guy Ottewell's 2014 Astronomical Calendar, meteor scientists Esko Lyytinen and Peter Jenniskens calculated the orbit of Comet 209/Linear, which passed by the Sun in 1803 and 1924 and is projected to return to perihelion on May 6th, and hypothesized that an intense meteor shower approaching 400 meteor per hour might result. The May issue of Astronomy magazine speculated more conservatively that Comet 209P/Linear meteors could approach rates of over 100 meteor per hour at the peak.

The Eta Aquarid Meteor shower is on the 6th. It normally averages 40 meteors per hour and may even reach levels comparable to the storm of 2013 which reached 140 meteors per hour in dark skies. The Eta Aquarids are comprised of debris shed from Comet 1P Halley which last passed this way in 1986 and will make a return trip in 2061. Comet Halley is currently approaching its aphelion (farthest from the Sun position) between Neptune and Pluto well below the plane of the Solar System. Inasmuch as it moves much more slowly in the outer part of its orbit than when close to the Sun, it will reach aphelion in 2023 and then start the long return journey.

Planet Plotting

Saturn is at opposition on the 10th at 2PM EDT and at its brightest (magnitude +0.1) for 2014. The planet is tilted away from Earth presenting spectacular views of the underside of its rings.

The magnitude scale is exponential and ranges from 1st magnitude to 6th magnitude for visible celestial objects. Any magnitude designated by a number greater than 6 is too dim to see. Sixth magnitude includes magnitudes 5.50 through 6.49 and 1.0 magnitude objects are 100 times brighter than 6.0 magnitude objects. A difference in magnitude of 1.0 is equivalent to a difference of brightness of approximately 2.5 (the difference between 6 and 1 is 5 and the fifth root of 100 is 2.512). Saturn will be visible in Libra throughout the night of the 10th and 11th when it rises at sunset and sets at sunrise. Magnitude +0.1 is about twice as bright as Saturn's normal magnitude which ranges from +0.6 to +0.9.

Evening planets in May also include Mercury, Jupiter, and Mars. Mercury appears at magnitude 0.0 to +1.1 in Taurus in the latter half of May right after the Sun sets. It is at greatest eastern elongation on the 25th when it is 23° away from the Sun and sets two hours after sunset. Jupiter sets in Gemini in the latter part of the evening ranging from an hour after midnight on the 1st to 11PM EDT at month's end. It dims slightly from magnitude -2.0 to -1.9 during the interval. Mars drops from magnitude -1.2 to -0.5 during May after its April opposition as Earth is rapidly distancing itself as it moves ahead of Mars in its orbit. Quite bright in Virgo, Mars outshines 1st magnitude Spica by 6 times in early May and by 4 times on the 31st.

Brilliant Venus (-4.4 to -4.2), Uranus (+5.9) in Pisces, and Neptune (+7.9) in Aquarius are morning planets. Neptune rises 3 hours before the Sun on the 15th, followed 1.5 hours later by Venus and Uranus which are separated by about 1°.

PlanetConstellationMagnitudePlanet Passages
SunAries, Taurus-26.8New Moon, 5/28, 2:40PM EDT
MercuryAries, Taurus, Gemini-1.8 to +1.1Max. Eastern Elongation 5/25, 3:00AM EDT
VenusPisces-4.1 to -4.0Uranus, 1.3°N, 5/15, 9AM EDT
MarsVirgo-1.2 to -0.5 
JupiterGemini-2.0 to -1.9 
SaturnLibra+0.1 to +0.2 
UranusPisces+5.9Venus, 1.3°N, 5/15, 9AM EDT
NeptuneAquarius+7.9 

May Moon

Lunation 1130, kicked off by the April 29th New Moon at 2:14AM EDT, provided an annular Solar Eclipse for the Indian Ocean and Antarctica. It ends 29.52 days later with the New Moon of May 28th at 2:40PM EDT. An exceptionally thin 30 hour old waxing crescent Moon is near the western horizon right after sunset on the 29th. It will be slightly south of where the Sun set.

The Full Moon of May occurs in Libra on the 14th at 3:16PM EDT. The May Full Moon was traditionally named the "Milk Moon" in Colonial America, probably because of the ancient tradition in England of milking the cows three times a day on May 1st. For Celts it was “Bright Moon” and Chinese call it the “Dragon Moon." To Medieval English it was “Hare Moon” and the Anishnaabe people (Chippewa and Ojibwe) of northern Michigan call it “Waabigwani-giizis” (Blossom Moon).

The Moon is at the farthest point in its orbit, 251,232 miles (63.39 Earth Radii) from Earth at apogee on the 6th at 6:24AM EDT. Perigee is at a distance of 228,107 miles (57.56 Earth Radii) on the 18th at 7:27AM EDT.

PlanetConstellationMagnitudeMoon PassageMoon Phase/Age
SunTaurus-26.82:40PM EST, 5/28New ~ 0 days
MercuryTaurus+1.10.6°S, Noon EDT, 5/30Waxing Crescent ~ 1.9 days
VenusPisces-4.02.0°N, Noon EDT, 5/25Waning Crescent ~ 26.41 days
MarsVirgo-0.93.0°S, 10AM EDT, 5/11Waxing Gibbous ~ 12.32 days
JupiterGemini-2.05.0°S, 10AM EDT, 5/4Waxing Crescent ~ 5.32 days
SaturnLibra+0.10.6°S, 8AM EDT, 5/14Waxing Gibbous ~ 15.24 days
UranusPisces+5.91.9°N, 4PM EST, 5/24Waning Crescent ~ 25.57 days
NeptuneAquarius+7.95.0°N, Midnight EDT, 5/21Waning Gibbous ~ 22.91 days




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