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April 2018 Skies

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April Skies

by Dick Cookman



Highlights: Comet Journal, Martian Landers, Meteor Showers, Planet Plotting, April Moon, Easter, April Fool's Day, Friday the 13th

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

Comet Journal

Tenth magnitude comet C/2016 R2 (PanSTARRS) is moving slowly northward between Auriga and Perseus, and will pass by Capella in early May before passing through perihelion on May 9th. It may reach 9th magnitude near perihelion and is expected to remain at 9th to 11th magnitude through the summer.

Mars Landers

This summary of the Mars Landers activities in the last month differs from past renditions due to political trends on Earth. The current acting NASA administrator is leaving on April 30th after filling in for Charles Bolden, the last NASA administrator who resigned in January, 2017, ending a nine year tenure. The precarious situation of NASA’s planetary exploration programs is illustrated in the following excerpts from the March 15th, 2015 article by the Planetary Society’s Casey Drier:

Despite the finding of the latest biennial Planetary Science Senior Review that rates the Opportunity Mission higher than every other current Mars mission, including those for Curiosity, the Mars Reconnaissance Orbiter, Mars Express, and Mars Odyssey, Senate testimony by the NASA administrator Bolden questioned continuation of the mission. He stated: Is the Opportunity Rover a Mission 'Whose Time Has Passed? "We cannot continue to operate instruments and missions whose time has passed, because I won't be able to put something like InSight on Mars in 2016…I have to make choices…”

The cost to operate the Opportunity rover is about $14 million per year. This is a little less than 1% of the beleaguered Planetary Science Division's budget, and about 0.08% of NASA's total budget. In 2012, InSight was selected as the next mission to land on Mars. Opportunity was running that year. Work on InSight began in earnest; funding peaked at $203.3 million in 2014 as assembly and integration of the spacecraft began. Again, Opportunity explored Mars that year. Same for 2015 as work on InSight continued. For 2016, the last year of InSight's development, NASA is requesting $92.1 million to finish and launch the spacecraft, less than in previous years. Suddenly, Opportunity is too expensive. The vast majority of the money that will ever be spent on InSight has already been spent. For the entirety of InSight's development, from 2012 to now, Opportunity continued to explore the martian surface. It's clearly not a choice between Opportunity and InSight, they've coexisted happily during the most expensive period of InSight's life cycle.

Has Opportunity's time passed? Well, it's been on Mars for over 11 years now, longer than any other mission to Mars' surface. That's a long time, but time used well. In addition to finishing the world's fastest (albeit only) martian marathon, it has helped to revolutionize our understanding of the role of liquid water in Mars' history. Its exploration is ongoing. In fact, it just discovered a rock "unlike any we've seen before" while searching for clay minerals near Marathon Valley. The pictures it returns to us every day are haunting and beautiful.

Bolden was right: there are choices to be made, but not the false choice between two stalwart missions and the next Mars lander. The choice we face is whether to fight for Opportunity and LRO or not. Let's choose—all of us—to fight for these missions and for all of the precious scientific discoveries they have yet to make. We lose them now, and they're likely gone forever. Congress has demonstrated a consistent willingness to add money for planetary exploration by adding funding for three years in a row. If NASA asked, it's likely that Congress would be happy to support both missions.

Meteor Showers

It should worth getting up early for the Lyrid Meteor Shower on the night of April 21/22 as it is one of the better showers of the year. It occurs a week before Full Moon and glare from the first quarter Moon will be minimal as it sets long before best viewing during the predawn hours. At that time Earth is plunging head on into the river of wayward comet debris abandoned during last few passages through the inner Solar System of long period Comet C/1861 G1 (Thatcher). It will seem as though the meteors come from the constellation Lyra which is close to the zenith in the southeastern sky before dawn. At least 15 to 20 meteors per hour will appear to emanate in all directions from Lyra like support ribs on an umbrella unless there is an outburst such as that in 1982 which produced up to 4 to 5 meteors per minute.

Planet Plotting

In April, Venus (-3.8) is in Aries and Taurus and shines brightly in the early evening western sky. Venus is about 10° above the horizon in the hour after sunset and rises higher in the sky during the month. 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 (-2.2 to -2.4) in Libra rises slightly south of east by 11:00 PM EDT in early April. It will be within 4° of the waning gibbous Moon on the 3rd. Later in the month Jupiter will rise before Venus sets and will grow brighter as it approaches opposition in May. On the 30th, the waning gibbous Moon will again pass within 4° from Jupiter.

Mars (+0.2 to -0.4) and Saturn (+0.5 to +0.4) in Sagittarius are morning planets rising after midnight. On April 2nd, at 8:00AM EDT, they are within 1.3° of one another and may be viewed before dawn when they are low in the south-southeast. On the 7th, Mars, Saturn, and the waning gibbous Moon will be in close proximity before dawn. Neptune (8.0) is in Aquarius and passed through Solar Conjunction in March. It may be found low in the southeast before dawn in April and is within 2° of the waning crescent Moon on the 12th. Uranus (+5.9) in Pisces and Aries reaches Solar Conjunction on the 18th and is not a viable target in April. On the morning after New Moon on the 15th, an extremely narrow crescent Moon is 4.4° SSE of Uranus.

Mercury (+5.3 to +0.5) is in Pisces and Cetus in April. It’s orbit inclination of 7° to the orbit of Earth, the largest of any solar system planet, causes Mercury to be the only planet to visit Cetus, all others are restricted to the zodiac as they circle the Sun. Mercury is not visible during the first half of April as it is at inferior conjunction with the Sun on April 1st. It may be seen in the glow of sunrise at month’s end when it reaches maximum western elongation on the 29th.

PlanetConstellation(s)MagnitudePlanet PassagesTime, Date
SunPisces, Aries-26.8New Moon9:57PM EDT, 4/15
MercuryPisces, Cetus+5.3 to +0.5Inferior Conjunction
Max. West Elongation
2:00PM EDT, 4/1
2:00PM EDT, 4/29
VenusAries, Taurus-3.9  
MarsSagittarius+0.3 to -0.4Saturn, 1.3°N8:00AM EDT, 4/2
JupiterLibra+2.2 to -2.4  
SaturnSagittarius+0.5 to +0.4Mars, 1.3°S8:00AM EDT, 4/2
UranusPisces, Aries+5.9Solar Conjunction10:00AM EDT, 4/18
NeptuneAquarius+8.0 to +7.9  

April Moon

April’s New Moon on the 15th at 9:57PM EDT is the beginning of Lunation 1179 which ends 29.38 days later with May’s New Moon on the 15th at 7:48AM EDT.

The Full Moon on the 29th at 8:58PM EDT is known as the “Grass Moon” and “Egg Moon”, celebrating grass sprouting and the end of the hen's molting season when egg production returns. The Celts called it the “Growing Moon”, and Colonial Americans called it the “Planter’s Moon.” Chinese refer to it as the “Peony Moon”, and it was the “Seed Moon” in Medieval England. Anishinaabe (Odawa and Ojibwe people) recognize it as “Pokwaagami-giizis” (Broken Snowshoe Moon.)

Lunar Apogee (maximum orbital distance) occurs on the 8th at 1:31AM EDT when the Moon is at 251123 miles (63.36 Earth radii). Perigee (closest to Earth) is 229108 miles or 57.81 Earth radii on the 20th at 10:41AM EDT.

Easter, April Fool's Day, Friday the 13th

April 1st is Easter, the 1st Sunday following the 1st Full Moon after the Spring Equinox. The 1st of April is also the 1st Sunday in April, which Congress established in 1986 as time change day (amended in 2007 to the 2nd Sunday in March when we turn our clocks forward on Saturday night as we switch over to nighttime losing time(NLT)). A similar governmental intervention into the measurement of time 436 years ago, started the tradition of "All Fool's Day" on April 1st. Folks who objected to Pope Gregory’s calendar change which corrected errors accumulated since Julius Caesar’s time were sent on "fool's errands" by more knowledgeable members of society when they tried to continue the tradition of celebrating New Years Day on April 1st.

Friday the 13th evolved as an unlucky day because the number 13 and Friday were both considered unlucky. Friday falls on the 13th either once, twice, or three times a year. If you are an Italian living in South America, the unlucky day would be Tuesday the 17th.

PlanetConstellationMagnitudeMoon PassageMoon PhaseMoon Age
SunPisces-26.89:57PM EDT 4/15New0 days
MercuryPisces+0.44.0°S, 5:00AM EDT, 4/14Waning Crescent27.83 days
VenusAries-3.85.0°S, 3:00PM EDT, 4/17Waxing Crescent1.71 days
MarsSagittarius+0.73.0°N, 2:00PM EST, 4/7Waning Gibbous21.20 days
4.0°N, 10:00AM EST, 4/3
4.0°N, 1:00PM EST, 4/30
Waning Gibbous
Waning Gibbous
17.03 days
14.50 days
SaturnSagittarius+0.51.9°N, 9:00AM EDT, 4/7Waning Gibbous20.99 days
UranusPisces+5.94.4°SSE, 2:00AM EDT, 4/16Waxing Crescent0.17 days
NeptuneAquarius+7.91.9°S, 7:00PM EDT, 4/12Waning Crescent26.41 days


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