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The Skies of August, 2021


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August Skies

by Dick Cookman

August 1, 2021


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

Focus Constellations: Ursa Minor, Draco, Cepheus, Cassiopeia, Camelopardalis, Ursa Major, Bootes, Corona Borealis, Ophiuchus, Hercules, Lyra, Cygnus, Aquila, Pegasus, Andromeda

Comet Journals

C2020 T2 (Palomar) is about 10th magnitude and was closest to Earth on May 12. It passed perihelion on July 10 and moves from Virgo to Libra in August. It will slowly dim as it retreats from the Sun and heads eastward along the ecliptic, returning to the Oort Belt.

Comet Faye moves from Aries to Taurus at 10th magnitude in August. Faye is closest to the Sun at perihelion on September 8 and closest to Earth in December. Comet 8P/Tuttle (2021) moves from Gemini to Hydra at 10th magnitude in August. Perihelion is on August 27 and the closest approach to Earth is in September. C/2021 O1 (Nishimura) moves from Gemini to Leo in August. It was discovered on July 21, 2021 and may reach 9th magnitude when near its August 12 perihelion.

Mars Landers

After shepherding the Ingenuity Helicopter through ten very successful test flights, the Perseverance Rover is preparing to conduct its first 11 day sampling mission. They plan to extract a rock core sample, conduct an examination of the sample, then hermetically seal it for preservation until it is picked up and returned to Earth in the next decade by a future mission.

Data collected from the 700+ marsquakes measured by the InSight Lander the last 2.5 years reveals a spectacular picture of the Martian interior. The planet’s crust has an upper layer 10 km. thick with apparently highly fractured rock and averages a total thickness between 24 and 72 km. This is much thinner than previously estimated. The entire lithosphere is 500 km. thick and overlies a mantle about 1060 km. thick. The 1860 km. radius of the core beneath the mantle is over half that of the planet. Earlier estimates were significantly smaller, the larger size requires a lower density than Earth’s core.

Curiosity is in the lower part of the Sulfate Unit and spent the first week of July preparing for its 32nd drilling event on a rock surface target named “Pontours” which occurred on July 7, 2021 (Sol 3171). The next two weeks were devoted to processing the sample and making observations of the surrounding rocks, sediments, and atmospheric conditions. The rover then resumed its ascent of Mt. Sharp and observation of the Sulfate Unit.

Meteor Showers

August Meteor showers include the Perseids, the Kappa Cygnids, and the Aurigids. The Perseids are one of the best showers of the year and the other two are minor showers. The Cygnids have to compete with the glare of the waxing gibbous Moon, and the Aurigids may produce enhanced activity this year.

  • August 12: Perseids. Active July 17 – August 24, Radiant 3h13m +58°, ZHR 100. 59km/sec. Waxing Crescent Moon, Progenitor: Comet 109P Swift-Tuttle
  • August 17: Kappa Cygnids. Active July 28 – September 2, Radiant 19h13m +53°, ZHR 3 to 5, 23 km/sec. Waxing Gibbous Moon, Progenitor: The meteor shower and Minor planet 2008 ED69 are thought to be remnants of a comet break up between 4000-1600 BC.
  • August 31: Aurigids. Active August 25 – September 4, Radiant 6h4m +39°, ZHR 1 to 6, 66km/sec. Waning Crescent Moon, Progenitor: Comet C/1911 Kiess

Planet Plotting

Uranus (+5.8 to +5.7) in Aries is a morning planet in August. Saturn (+0.2 to +0.3) in Capricornus rises at sunset on the 1st and sets at sunrise. On the 2nd, it is at Opposition. Jupiter (-2.7), which reaches Opposition on the 19th is in Aquarius and Capricornus. It rises an hour after Saturn and Neptune (+7.9 to +7.8) rises an hour later in Aquarius.

Mercury (+1.0 to -1.9) in Cancer and Leo is low in the southwestern sky after sunset in the 1st half of the month after its Superior Conjunction with the Sun on the 1st. Venus (-3.8) in Leo and Virgo dominates the early evening southwestern sky and is briefly joined by Mars (+1.8) in Leo in early August.

The waxing crescent Moon appears to pass evening planets Mercury, Mars, and Venus from August 9 to 11. The waxing gibbous Moon appears to pass morning planets Saturn and Jupiter from the 20th through the 22nd. The waning gibbous moon will pass Neptune on the 23rd and Uranus on the 28th.

PlanetConstellation(s)MagnitudePlanet PassagesTimeDate
SunPisces, Aries-26.5New Moon9:50AM EDT8/8
MercuryCancer, Leo, Virgo-1.9 to.0.0Superior Conjunction
Mars, 0.8°N
10:00AM EDT
Midnight EDT
8/1
8/18
VenusLeo, Virgo-3.8 to -3.9   
MarsLeo+1.8Mercury, 0.8°SMidnight EDT8/18
JupiterAquarius, Capricornus-2.7Opposition8:00PM EDT8/19
SaturnCapricornus+0.2 to +0.3Opposition2:00AM EDT8/2
UranusAries+5.8 to +5.7   
NeptuneAquarius7.8   

August Moon

The New Moon of August is on the 8th at 9:50AM EDT. It is the beginning of Lunation 1220, which ends 28.96 days later with the New Moon of September 6 at 8:51PM EDT. The Full Moon of August is on the 22nd at 8:02AM EDT. It is commonly known as “Grain or Green Corn” Moon. In colonial times, the Full Moon of August was called the “Dog’s Day” Moon and in Medieval England, it was the “Corn” Moon. The Chinese call it “Harvest” Moon and the Celts named it the “Dispute” or “Barley” Moon.

Of the 13 Grandmother Moons during each year, the Anishinaabe (Odawa & Ojibwe) people recognize the 8th Moon as “Manoominike-giizis” (Ricing Moon). According to Earth Haven Farm in Ontario, it has the following cultural teaching that explains the cycle of life and nature for the 8th Moon. “We honor the Thimbleberry which produces an abundance of fruit once every three years. It was one of the first plants put on Mother Earth, and its purpose is to protect the Sacred Circle of Life by allowing us to recognize and understand the teachings that come from the Spirit World.”

Lunar Apogee (maximum lunar distance) is on August 2 at 3:35AM EDT. The Moon will be 251,289 miles from Earth. Perigee distance (minimum lunar distance) is 229,363 miles on the 17th at 5:16AM EDT, 42 hours before Full Moon. The Full Moon occurs when close to the perigee point in its orbit and appears larger and brighter than normal. However, it fails to achieve “Supermoon” status because it is too far away.

PlanetConstellationMagnitudeMoon PassagesMoon PhaseMoon Age
SunCancer-26.89:50AM EDT, 8/8New0 days
MercuryLeo-1.13.2°NNE, 2:00AM EDT, 8/9Waxing Crescent27.75 Days
VenusVirgo-3.94.0°N, 3:00AM EDT, 8/11Waxing Crescent0.72 Days
MarsLeo1.84.0°N, 9:00PM EDT, 8/9Waxing Crescent0.36 Days
JupiterCapricornus-2.74.0°S, 1:00AM EDT, 8/22Waxing Gibbous13.63 Days
SaturnCapricornus0.34.0°S, 6:00PM EDT, 8/20Waxing Gibbous12.74 Days
UranusAries5.71.5°S, 5:00AM EDT, 8/28Waning Gibbous19.80 Days
NeptuneAquarius7.84.0°SE, 10:00PM EDT, 8/23Waning Gibbous15.51 Days


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