Archive for month: June, 2020

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

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

Comet Journals

Comet C/2017 U6 (Lemmon) is approaching 5th magnitude as it moves through Hydra and into Sextans in the latter part of June, and through Leo & Virgo into Coma Berenices in July. It is a long period comet which dropped out of the Oort Cloud, briefly dropped below the plane of the solar system when reaching perihelion (closest to the Sun – 0.91AU) on June 18, 2020, and is closest to Earth on the 29th. It will rise through the solar system plane in July and return to the Oort Cloud.

Comet C/2020 F8 (SWAN) just passed through Auriga and will reach Gemini by July 31. It is at 7th magnitude and will dim in July.

Comet 58P/Jackson-Neujmin is a 10th magnitude comet in Cetus and will dim as it enters Orion at the end of July.

Comet C/2017 T2 PanSTARRS is 8th magnitude comet and is also dimming as it exits Ursa Major and moves into Coma Berenices in July. It is a long period comet which rose out of the Oort Cloud below the solar system on an orbit tilted at over 60 degrees to the solar system plane. It passed through perihelion (closest to the Sun) on May 4, 2020, and will drop back through the plane of the solar system in September and embark on its long journey back to the Oort Cloud.

Comet C/2020 F3 (NEOWISE) is moving northward as it departs from Orion at 7th magnitude. It will move northward through Gemini and pass between Ursa Major and Leo Minor after passing through perihelion on July 3. It will be closest to Earth on the 23rd when it may be visible to the naked eye providing that its passage by the Sun doesn’t cause disintegration.

Mars Landers

InSight is the first Mars mission specifically dedicated to uncovering the secrets beneath the surface. It landed on Mars in November 2018 and set up its seismometer. Insight detected a quake in April, 2019 and has detected over 450 “marsquakes” so far. These measurements reveal that Mars is tectonically active in some areas, possibly due to volcanic activity or other internal heat sources. Magnetometer data shows that Mars has areas with strongly magnetized basement rock. Insight’s heat probe is a 16-inch-long (40-centimeter-long) spike “mole” equipped with an internal hammering mechanism. As it burrows into the soil, it pulls a ribbonlike tether with embedded temperature sensors along its length. The mole has had difficulty digging through the cohesive “duricrust” near the surface. There is insufficient friction between the mole and sides of the hole, causing the mole to bounce in place when hammering. It became lodged at a very shallow depth then popped out of the hole in October and again on Jan. 21. After the limited success with side pressure, the team decided to push down on the back cap while avoiding damage to the tether and has achieved success in slowly burrowing further.

Curiosity is on the border Glen Torridon, the clay-bearing unit in the valley adjacent to Vera Rubin Ridge on 16,404 foot Mt. Sharp at the center of Gale Crater, the ancient remnant of a massive impact. After the March drive up onto younger rocks of the Greenheugh pediment which is beyond and above the valley, scientists determined from drill cuttings at Edinburgh and Glasgow in April and early May that Greenheugh pediment sandstones represent a totally different environment of deposition than the older mudstones of the valley. On Sol 2778 (May 29) the rover was directed to hit the road again, descend from the pediment, and head toward the “sulfate bearing unit” farther up the slopes of Mt. Sharp after brief stops at a landslide at the base of the pediment scarp and at Bloodstone Hill, a light toned mound at the eastern edge of the pediment.

Meteor Showers, Asteroid Surprises

There are 3 meteor showers in late June and early July. The best is the Bootid shower at the end of June which has to compete with the last quarter Moon in nearby Leo. The two other showers are relatively weak, with the Pegasids in southern skies. The Phoenicids are also buried in southern hemisphere skies as are three additional showers at the end of July.

June 27: Bootids. Active June 26-July 2. Radiant 14h56m +48°, ZHR variable 0-100+. 18 km/sec. Waxing Crescent & Gibbous Moon. Progenitor: Comet 7P Pons-Winnecke, a short-period comet orbiting the Sun once every 6.37 years which was last at perihelion in January, 2015.

July 9: Pegasids. Active July 7-13, Radiant 22h40m +15°, ZHR 3, 47 km/sec. Waning Gibbous Moon. Progenitor: Long period Comet C/1979 Y1 (Bradfield) which has an orbital period of 300 years and was last at perihelion in Feb. 1980.

July 13: Phoenicids. Active July 10-16, Radiant 2h08m -43°, ZHR Variable 3-10, 35 km/sec. Waning Crescent Moon. Progenitor: long-lost Comet D/1819 W1 (Blanpain) with a current remnant, short period Comet 289P/Blanpain, which has an orbital period of 5.31 years and was last at perihelion in Dec. 2019.

Summer Solstice

The June Solstice on June 20 is at 5:44PM EDT. The following link leads to Mary Stuart Adams’ website, the Storyteller’s Night Sky. Her website and other media presentations achieve such a remarkable combination of Astronomy, Mythology, and History that audiences tune in weekly or even more frequently. For this solstice, I highly recommend going to:

https://storytellersnightsky.com/summer-solstice-in-the-shadow-of-eclipse-with-mary-stewart-adams-hosted-online-june-16-by-ford-house for a much more literary story than is normally presented in this newsletter. In addition, you may be so enthralled with her work that you, too, become a frequent visitor.

Planet..Constellation(s).Magnitude.Planet Passages.Time.Date
Sun…..Taurus, Gemini -26.8……..New Moon….2:41AM EDT..6/21
Sun…..Gemini, Cancer -26.8……..New Moon….1:33PM EDT..7/20
Mercury.Gemini…+5.0 to -0.7…Max. West Elong..11:00AM EDT 7/22
…………………………………………………….Inferior Conjunct.11:00PM EDT 7/30
Venus…Taurus…-4.4 to -4.7 to -4.3
Mars….Pisces…-0.5 to -1.1
Jupiter.Sagittarius……-2.6……..Opposition…4:00AM EDT 7/14
Saturn..Capricornus..+0.2 to +0.1….Opposition…6:00PM EDT 7/20
………………Sagittarius
Uranus..Aries……..+5.8
Neptune.Aquarius…..+7.9 to +7.8

Planet Plotting

Skies in early July are replete with brilliant planets. With a small telescope you can see all seven planets, then look down on the ground for #8. Jupiter (-2.6) in Sagittarius and Saturn (+0.2 to +0.1) in Capricornus and Sagittarius start the parade when they rise in the east in the early evening and are brightest when they are due south a midnight at Opposition on the 14th and 20th respectively. Neptune (+7.9 to +7.8) in Aquarius follows, rising after midnight and, not to be outdone, Mars (-0.5 to -1.1) in Pisces, makes its appearance soon after.

Mars makes a big jump in apparent size and brightness in July as it approaches Opposition in October. The 2020 opposition finds both Earth and Mars relatively close to their perihelion (closest to the Sun) positions, placing Mars at a relatively close 38+ million miles (half as far as it is right now). Apparent diameter of Mars will double between now and October making the disk appear 4 times larger (don’t you just love π r^2?).
Uranus (+5.8 to +5.9) in Aries rises a couple of hours before dawn and Venus (-4.4 to -4.7 to -4.3) in Taurus rises an hour later in Taurus. Wait till mid-July to see Mercury (+5.0 to -0.7) in Gemini make its presence known after Venus rises. Mercury is a maximum Western Elongation on the 22nd and reaches Inferior Conjunction on the 30th.

The waning gibbous Moon is 1.9° from Jupiter at 6:00PM EDT on the 5th, and 2.0° from Saturn at 5:00AM EDT on the 6th. It is 4.0° from Neptune at 3:00AM EDT on the 10th and 2.0° from Mars on the 11th. The waning crescent Moon passes within 4.0° of Uranus at 8:00AM EDT on the 14th, 3.0° from Venus on the 17th, and 4.0° from Mercury on the 18th.

June/July Moon

The New Moon of June on the 24th at 2:41AM EDT is the beginning of Lunation 1206 which ends 29.43 days later with the New Moon on July 20 at 1:33PM EDT. The Full Moon of July on the 5th at 12:44AM EDT is commonly known as the “Thunder or Hay” Moon and offers us a penumbral lunar eclipse visible in most of North America and in South America, Western Europe, Africa, and Antarctica. It was called the “Summer Moon” in colonial times and in Medieval England it was the “Mead Moon.” Celts named it the “Moon of Claiming” and the Chinese call it the “Hungry Ghost Moon”. Anishinaabe (Odawa and Ojibwe) people recognize it as “Miin-giizis” (Berry Moon).

Lunar Perigee (minimum orbital distance) occurs on June 29 at 10:13PM EDT when the Moon is at a distance of 229,260 miles (56.00 Earth radii). Apogee is on July 12 at 3:27PM EDT when the Moon’s distance is 251,158 miles (63.37 Earth radii).

Planet.Constellation.Magnitude.Moon Passages.Moon Phase. Moon Age
Sun…..Taurus…….-26.8……2:41AM EDT, 6/21..New…0 days
Sun…..Gemini…….-26.8……1:33PM EDT, 7/20..New…0 days
Mercury.Aquarius……+1.0……4.0°N, Midnight EDT, 7/18
…………………………..Waning Crescent…..26.89 days
Venus…Aries………-4.3……3.0°N, 3:00AM EDT, 7/17
…………………………..Waning Crescent…..26.01 days
Mars….Sagittarius…-0.7……2.0°S, 4:00PM EDT, 7/11
…………………………..Waning Gibbous……20.55 days
Jupiter.Sagittarius…-2.6……1.9°S, 6:00PM EDT, 7/5
…………………………..Waning Gibbous……14.64 days
Saturn..Sagittarius…+0.2……2.0°S, 5:00AM EDT, 7/6
…………………………..Waning Gibbous……15.10 days
Uranus..Aries………+5.8……4.0°S, 8:00AM EDT, 7/14
…………………………..Waning Crescent…..23.22 days
Neptune.Aquarius……+7.9……4.0°S, 3:00AM EDT, 7/10
…………………………..Waning Gibbous……19.01 days