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June 2019 Skies

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June Skies

by Dick Cookman


Highlights: Comet Journal, Martian Landers, Meteor Showers, Summer Solstice, Planet Plotting, June Moon

Focus Constellations: Cancer, Leo, Leo Minor, Coma Berenices, Virgo, Bootes, Corona Borealis, Ophiuchus, Hercules, Lyra, Cygnus, Draco, Cepheus, Cassiopeia, Camelopardalis, Ursa Major, Ursa Minor

Comet Journals

C/2018 Y1 (Iwamoto) is an evening comet at 12th magnitude in Perseus which sets slightly after the Sun on June 1 and before sunset on June 30. It moves eastward until July after which it moves north northwestward through Perseus as it exits the inner solar system and returns to its aphelion between the Oort Cloud (10000+ AU’s) and Kuiper Belt (30 - 50 AU’s), the normal homes for longer period comets. C/2018 R3 (Lemmon) is brighter than Iwamoto at 11th magnitude as it moves through Camelopardalis and Lynx in June and passes through perihelion on June 7. It then moves southeastward into Leo in August as it exits the inner solar system on its return trip beyond the Kuiper Belt.

Mars Landers

Opportunity’s obituary: The rovers landed on Mars in 2004. Spirit explored for 1892 Martian days (sols) until Mayday, 2009 when the plucky rover became stuck in the sand after traveling a total of 7.73 kilometers. It maintained contact until March, 2010 when the rover became silent. Opportunity steadily continued on until June, 2018 before ending its 45.16 kilometer, 5111 Sol tour and permanently lost contact during a planet wide dust storm on Mars. Both rovers and the scientific teams in control of operations revolutionized understanding of Mars and set the stage for subsequent exploration.

The InSight lander arrived on Elysium Planitia on Mars on Nov. 26, 2018. After unfurling the solar panels and radio antenna and deploying its seismometer, the mole carrying the HP3 heat probe package burrowed into the ground. Although the heat probe got stuck soon after it started digging, teams analyzing its data still hope they can free the mole from the obstruction that halted its progress more than 3 months ago, but the mission’s chief scientist says the chances of completing the heat probe experiment — one of InSight’s two main science instruments — may not look promising.

HP3’s metallic mole began burrowing into the Martian soil Feb. 28, aiming to reach a depth of up to 16 feet (5 meters) — deeper than any previous Mars lander — with a series of thousands of hammer blows planned in several stages over several weeks. Within minutes, an obstruction stopped the mole at a depth of roughly 1 foot (30 centimeters), diverting the probe to a tilt of roughly 15 degrees. Another four-hour hammering session March 2 produced no further progress, and mission managers ordered a stop to the digging operation to allow engineers to evaluate the situation.

The Curiosity Rover is investigating Glen Torridon the clay-bearing unit adjacent to Vera Rubin Ridge, which is on the flank of 16,404 foot Mt. Sharp at the center of Gale Crater. Curiosity drilled a piece of bedrock nicknamed Aberlady on Sol 2370 (April 6). Analysis of the samples reveals the most clay rich composition of any sample yet examined on Mars. Clay minerals are often found in water deposits. When sediment is carried by wind and water into a water body, the coarser grain pebbles and sand settle first in the nearshore area characterized by active waves and the finer silts and clays are carried out to deeper quiet water areas and slowly settle to form a muddy bottom. Long term deposition gradually produces thick layers which may eventually lithify into hard rock with abundant clay minerals such as mudstone and shale. The rocks found in Glen Torridon suggest that nearly 3.5 billion years ago the area was a large lake which eventually dried up, and the buried sediment was compacted into mudstone.

So far, evidence collected on Mars indicates that conditions billions of years ago were favorable for life. Moderate temperatures, lakes with low salinity and fairly neutral acidity, and a much thicker atmosphere combined to form environments in which life could thrive. The final proof would be the discovery of fossils, an activity not included in the design parameters of Curiosity and the other rovers. Those parameters include search for the chemical evidence of ancient or current life, not the physical evidence provided by fossils. That is a task for future rovers or human explorers.

Meteor Showers

In late June, the best meteor shower is the Bootid Shower in the relatively dark waning crescent Moon skies unpolluted by unshielded outdoor lighting.

  • June 7: Arietids. Peak 16hr 0min UT Active May 22-Jul 2. Radiant 02h56m 24°. Radio Meteors. 37 km/sec. After New Moon. The shower is of uncertain parentage with the near-Earth asteroid 1566 Icarus and Comet 96/P Machholtz as likely candidates.
  • June 16: Lyrids Active June 11-June 21. Radiant 18h32m 35°. ZHR 0 to 5. 31 km/sec. Before and after Full Moon. Progenitor: Comet C/1861 G1 Thatcher
  • June 27: Bootids Active June 26-July 2. Radiant 14h26m 48°. ZHR 0 to 100+. 18 km/sec. Waning Crescent Moon. Progenitor: Comet 7P/Pons-Winnecke

Summer Solstice

On Friday, June 21 at 11:54 AM EDT the Earth’s northern hemisphere will be tilted directly toward the Sun which is 68.5° above the southern horizon, its highest position of the year. The day will be the longest of the year and the night will be shortest. The waning gibbous Moon will arc through the night sky on its southernmost path of the year. The northern hemisphere receives its most direct rays of the Sun on the this day but the warmest part of the northern hemisphere’s summer lags behind until July and August because the atmosphere, land, and oceans require extra time to warm up.

Earth temperature is a balance between solar gain and heat loss to space. Northern hemisphere heat gain increases each day as the June solstice approaches because these gains exceed loses. The difference between the two is greatest at the solstice and even though the difference gradually decreases after the solstice, gains continue to exceed loses until well into August. The ancient Egyptians noticed that the maximum heat of summer was in the “dog days of August” following the helical rising of Sirius, the first magnitude star of Canis Major (the Great Dog). This event (Sirius rising with the Sun) also marked the start of the Nile flooding and heralded the adoption of the first calendar based on the solar year.

PlanetConstellation(s)MagnitudePlanet PassagesTime, Date
SunAries, Taurus-26.8New Moon6:02AM EDT, 6/3
MercuryTaurus, Gemini, Cancer-1.0 to +1.2Mars, 0.2°S
Max. East Elongation
9:00PM EDT, 6/18
7:00AM EDT, 6/23
VenusAries, Taurus-3.8  
MarsGemini, Cancer+1.8Mercury, 0.2°N9:00PM EDT, 6/18
JupiterOphiuchus-2.5 to -2.4  
SaturnSagittarius+0.3 to +0.1  
UranusAries+5.9 to +5.8  

Planet Plotting

Venus (-3.8) in Aries and Taurus, Uranus (+5.9 to +5.8) in Aries, and Neptune (+7.9) in Aquarius grace eastern predawn skies as Jupiter (-2.5 to -2.4) in Ophiuchus, and Saturn (+0.3 to +0.1) in Sagittarius rise well before midnight and are in the western sky before sunrise. Mercury (-1.0 to +1.2) in Taurus and Cancer and Mars (+1.8) in Gemini and Cancer are evening planets visible in the west after sundown. Mercury is within 0.2° of Mars at 9:00PM EDT on the 18th and Mercury is farthest from the Sun in the sky on the 23rd when it is at maximum eastern elongation. Earth is visible beneath your feet all month.

The waning crescent Moon is 3° from Venus at 2PM EDT on the 1st and 5.0° from Uranus at 6:00AM EDT on the 27th. The Moon’s waxing crescent is 4° from Mercury at Noon EDT on the 4th and 1.6° from Mars at 11:00AM EDT on the 5th. A waning gibbous Moon is 0.4° from Saturn at Midnight EDT on the 18th and 4° from Neptune at 9:00PM EDT on the 23rd. The waxing gibbous Moon is 2.0° from Jupiter at 3:00PM EDT on the 16th.

June Moon

The New Moon of June is on the 3rd at 6:02AM EDT. It is the beginning of Lunation 1193 which ends 29.37 days later with the New Moon of July on the 2nd at 3:16PM EDT which coincides with total solar eclipse in Chile and Argentina.

June’s Full Moon on the 17th is at 4:31AM EDT. The June Moon is known as the “Rose, Flower, or Strawberry Moon”. Colonial Americans called the June Moon the “Rose Moon” and Celts called it the “Moon of Horses”. It was named the “Dyan Moon” in Medieval England. Chinese refer to it as the “Lotus Moon” and the Anishinaabe (Odawa and Ojibwe) people recognize it as “Odemiini-giizis” (Strawberry Moon.)

Lunar Perigee (minimum orbital distance) is on the 7th at 7:15PM EDT when the Moon is at a distance of 228,978 miles. (57.78 Earth radii). Apogee occurs on the 23rd at 3:50AM EDT when the Moon is at 251,375 miles (63.43 Earth radii).

PlanetConstellationMagnitudeMoon PassagesMoon Phase, Moon Age
SunTaurus-26.86:02AM EDT, 6/3New, 0 days
MercuryTaurus-1.14.0°S, Noon EDT, 6/4Waxing Crescent, 1.25 days
VenusAries-3.83.0°S, 2:00PM EDT, 6/1Waning Crescent, 27.80 days
MarsGemini+1.81.6°S, 11:00AM EDT, 6/5Waxing Crescent, 2.21 days
JupiterOphiuchus-2.52.0°N, 3:00PM EDT, 6/16Waxing Gibbous, 13.37 days
SaturnSagittarius+0.20.4°S, Midnight EDT, 6/18Waning Gibbous, 14.65 days
UranusAries+5.85.0°S, 6:00AM EDT, 6/27Waning Crescent, 24.00 days
NeptuneAquarius+7.94.0°S, 9:00PM EDT, 6/23Waning Gibbous, 20.62 days

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