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July 2019 Skies

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July Skies

by Dick Cookman



Highlights: Comet Journal, Martian Landers, Meteor Showers, Intergalactic Space, Planet Plotting, July Moon

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


Comet Journals

C/2018 N2 (ASASSN) is an 11th magnitude comet moving northward through the head of Cetus which rises in the wee hours after midnight. It will slowly move through northern hemisphere skies for the next two years. Even at perihelion on November 11, the comet will probably not exceed 10th magnitude in brightness as it moves perpendicular to the plane of the solar system between Mars and Jupiter. Since its orbit around the Sun takes more than 2 million years, seeing it is probably a once in a lifetime event, maybe even once in the lifetime of the human race. C/2018 R3 (Lemmon) is at 12th magnitude as it moves from Lynx to Leo in July after passing through perihelion on June 7. After moving southeastward into Leo in August it will exit the inner solar system on its return trip beyond the Kuiper Belt.

Mars Landers

The Insight lander arrived on Elysium Planita of Mars on Nov 26, 2018. After unfurling the solar panels and radio antenna and deploying its seismometer, the mole carrying the Heat Flow and Physics Properties Package (HP3) began burrowing into the ground on Feb. 28, aiming to reach a depth of up to 16 feet (5 meters). But it became stuck at a depth of 30 centimeters, possibly due to an obstruction or other issue. Project scientists and engineers do not believe that the cause is either the mole hitting a rock it cannot push aside or a snag in the mole’s tether within the instrument’s housing. The most likely hypothesis and — importantly — one for which they can do something to help the mole, is that it is stuck because of a lack of friction with the surrounding regolith. This means the mole simply bounces in place when it attempts to hammer deeper into the surface. On June 5, they decided to lift the support structure to examine the mole.

On June 28, InSight’s robotic arm, designed to place instruments onto the Martian surface, lifted the support structure for the HP3 and uncovered the mole as part of efforts to troubleshoot the instrument. They concluded that pressing down on the surface adjacent to the instrument (with the robotic arm) may increase friction and allow the mole to gain traction.

In its continuing quest for evidence of past or present life on Mars, Curiosity Rover is investigating Glen Torridon, the clay-bearing unit adjacent to Vera Rubin Ridge on 16,404 foot Mt. Sharp at the center of Gale Crater. After spending almost 2 years examining Vera Rubin Ridge, the rover descended almost 15 meters into a trough south of the ridge on the northern flank of Mt. Sharp to explore the northern part of the clay-bearing unit. Before Curiosity arrived on Mars in 2012, mission scientists selected a Gale Crater landing because spectral signatures of clay were measured by NASA orbiters in the Glen Torridon area and clay deposits are often formed in water, which is essential for life. Airborne fine grains of clay tend to be transported, not deposited, by wind. In water, minimal current or wave activity such as found in stagnant ponds or deep water lakes and seas allows clay to settle to the bottom.

Curiosity drilled into a site in the clay-bearing unit nicknamed Aberlady on Sol 2370 (April 6). Analysis of the sample revealed the most clay rich content of any sample yet examined on Mars. On Sol 2384, (April 21, 2019), rock powder was obtained from an adjacent rock drilled at Kilmarie. Processing and analysis of the powder again revealed a very high clay mineral content. Further analysis and interpretation of analysis data may allow for earthbound scientists to develop deeper insight into the origin of the clay, deposition conditions, and changes resulting from varying environmental conditions on Mars during the billions of years since formation.

After completion of drilling, the rover continued its traverse through Glen Torridon, driving over and around pebbles and rocks, rippled sand, and ridges with bedrock layers at the surface of the clay-bearing unit. The next destination is the sulfate unit and Greenheugh Pediment farther up Mt. Sharp.

Meteor Showers

July’s best meteor shower viewing is the Delta Aquarid Shower which averages 20 meteors per hour in dark skies free of light pollution. Meteors emanate out of the south-southwestern sky in predawn hours following waning crescent Moonset.

  • July 9: Pegasids. Active July 7-13. Radiant 22h40m +15°. ZHR 3. 70 km/sec. 1st Quarter Moon. Progenitor: C/1979 Y1 (Bradfield).
  • July 28: Delta Aquarids Active July 12-Aug 19. Radiant 22h36m -16°. ZHR 20. 41 km/sec. Waning Crescent Moon. Progenitor: Comet 96P / McCholtz
  • July 30: Alpha Capricornids Active July 3-Aug 15. Radiant 20h28m -10°. ZHR 0 to 100+. 23 km/sec. Waning Crescent Moon. Progenitor: Comet 169/P Neat

Intergalactic Space

Although telescopic views of the planets are relatively distorted by their proximity to the western, southern, and eastern horizon in July, the western evening sky is the window to deep space which is normally closed in other seasons when we must peer through the disk of our galaxy, the Milky Way. On summer evenings, the north pole of the galaxy’s disk is in the western sky in Coma Berenices where far fewer Milky Way stars intervene and block views of the depths of space outside the galaxy. Observation with telescopes with apertures of 6 inches or more through this window reveals scattered Milky Way globular star clusters and the distant galaxies and clusters of galaxies in Leo, Virgo, Coma Berenices, Canes Venetici, and Ursa Major. In the last 100 years, telescopic observations by amateur astronomers, professional astronomers, university astronomers, NASA, and others worldwide have altered our perception of the universe and our place in it. Even so, this perception remains exceedingly myopic and is destined to be drastically altered by discoveries yet to come.

PlanetConstellation(s)MagnitudePlanet PassagesTime, Date
New Moon
New Moon
3:16PM EDT, 7/2
11:12PM EDT, 7/31
MercuryCancer, Gemini+1.3 to +2.1Mars,4.0°N
Inferior Conjunction
10:00AM EDT, 7/6
7:00PM EDT, 7/21
VenusTaurus, Gemini, Cancer-3.8  
MarsCancer, Leo+1.8Mercury, 4.0°S10:00AM EDT, 7/6
JupiterOphiuchus-2.4 to -2.3  
SaturnSagittarius+0.1 to +0.2Opposition1:00PM EDT, 7/9

Planet Plotting

July begins with Venus (-3.8) in Taurus rising an hour before the Sun. At months end, the interval is less than 15 minutes. Uranus (+5.8) in Aries, and Neptune (+7.9) in Aquarius are in the southeast and south respectively at sunrise. Saturn (+0.1 to +0.2) in Sagittarius rises and sets with the Sun at opposition on the 9th and Jupiter (-2.4 to -2.3) in Ophiuchus is up before sunset and sets before Saturn. Mercury (1.3 to +2.1) in Cancer and Gemini and Mars (+1.8) in Cancer and Leo are evening planets visible in the west after sundown. Mercury is within 4.0° of Mars at 10:00AM EDT on the 6th and is at inferior conjunction with the Sun at 7:00PM EDT on the 21st.

The waning crescent Moon is 2.5° from Venus at 11:40PM EDT on the 1st and 5.0° from Uranus at 3:00AM EDT on the 25th. The Moon’s waxing crescent is 3° from Mercury at 5;00AM EDT on the 4th and 0.09° from Mars at 2:00AM EDT on the same night. A waning gibbous Moon is 4° from Neptune at 4:00AM EDT on the 21st. The waxing gibbous Moon is 2.0° from Jupiter at 4:00PM EDT on the 13th and 0.2° from Saturn at 3:00AM EDT on the 16th.

July Moon

July’s New Moon on July 2 at 3:16PM EDT creates a total solar eclipse in the South Pacific, Chile, and Argentina. It is the beginning of Lunation 1194 which ends 29.32 days later with the another New Moon on the 31st at 11:12PM EDT. Some have called the latter a “Black” Moon because it is the second New Moon during a single calendar month for North American inhabitants west of the Atlantic time zone (and ATZ time zone areas on standard time).

July’s Full Moon on the 16th at 5:38PM EDT is partially eclipsed in Europe, Africa, and Asia. The July Moon is known as the “Thunder, or Hay Moon”. Some prefer to call it the “Buck Moon”. Colonial Americans called it the “Summer Moon” and Celts called it the “Moon of Claiming”. It was named the “Mead Moon” in Medieval England. Chinese refer to it as the “Hungry Ghost Moon” and the Anishinaabe (Odawa and Ojibwe) people recognize it as “Miin-giizis” (Berry Moon.) Lunar Perigee (minimum orbital distance) is on the 5th at 1:00AM EDT when the Moon is at a distance of 226,009 miles (57.03 Earth radii). Apogee occurs on the 20th at 7:59PM EDT when the Moon is at 251,954 miles (63.58 Earth radii).

PlanetConstellationMagnitudeMoon PassagesMoon PhaseMoon Age
3:16PM EDT, 7/2
11:12PM EDT, 7/31
0 days
0 days
MercuryCancer+1.63.0°N, 5:00AM EDT, 7/4Waxing Crescent1.57 days
VenusTaurus-3.82.5°S, 11:40PM EDT,7/1Waning Crescent28.54 days
MarsCancer+1.80.09°S, 2:00AM EDT, 7/4Waxing Crescent1.45 days
JupiterOphiuchus-2.42.0°N, 4:00PM EDT, 7/13Waxing Gibbous11.03 days
SaturnSagittarius+0.10.2°S, 3:00AM EDT, 7/16Waxing Gibbous13.99 days
UranusAries+5.85.0°S, 3:00AM EDT, 7/25Waning Crescent22.49 days
NeptuneAquarius+7.84.0°S, 4:00AM EDT, 7/21Waning Gibbous18.53 days

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