What's Up in July: Activity in the skies above rising right along with temperatures - pressherald.com

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This map represents the night sky as it appears over Maine during July. The stars are shown as they appear at 10:30 p.m. early in the month, at 9:30 p.m. at midmonth, and at 8:30 p.m. at month’s end. Mars, Saturn and Venus are shown at their midmonth positions. To use the map, hold it vertically and turn it so that the direction you are facing is at the bottom. Sky Chart prepared by Seth Lockman

We have now reached the first full month of summer, and July holds plenty of action and many interesting events. There is nothing like gazing deeply into a clear and warm summer night with some understanding of what we are really looking at to spark our imaginations and create a desire in us to learn more about where we really are and the nature of our celestial neighbors that share the sky and our little corner of the universe with us.

The highlights this month include a very close conjunction of our two next-door neighboring planets, Venus and Mars on July 12. Jupiter and Saturn are both rising before midnight now and are approaching their oppositions next month when they will be at their best for the year. The asteroid Vesta can be seen traversing a rich field of galaxies in Virgo now. Pluto reaches opposition on July 17 and there will be several nice conjunctions of the moon with bright planets. No less than three comets will be visible this month through telescopes, and the Delta Aquarid meteor shower peaks on July 29 emanating from an area of the sky in Aquarius near where Jupiter is now located.

Amateur astronomers gathered shortly before sunrise on June 10 with hopes of watching the partial eclipse at the Eastern Prom in Portland. Staff photo by Shawn Patrick Ouellette Buy this Photo

We are just past an eclipse season now, with the next one not due until Dec. 4, about two weeks before the winter solstice. That will be a total solar eclipse visible only over parts of Antarctica, taking roughly an opposite path across the earth that the recent June 10 annular solar eclipse took over Greenland and Russia. That one was only a partial eclipse for us here right at sunrise, but it was still well worth seeing and photographing. That was the strangest sunrise we had in 63 years and I was surprised about how few people shared the beach with me to enjoy this great event.

The partial eclipse seen through the clouds from the Eastern Prom on June 10. Staff photo by Shawn Patrick Ouellette Buy this Photo

If I could have seen it the very second it rose out of the Atlantic, the sun would have looked like a giant fiery canoe flying just above the ocean with its luminous bow and stern curving toward the heavens. That partial eclipse should prepare us for the next total solar eclipse visible right here over Maine starting in Bethel and passing right over our highest point, Mt. Katahdin, in less than three years on April 8, 2024.

As for this July, carefully watch and try to photograph Mars and Venus as they appear to get closer each evening until their close conjunction on July 12 when they will be separated by less than the width of the full moon, which is half a degree. Just as Jupiter and Saturn get fairly close every 20 years, Venus and Mars get fairly close about every two years, but this will be their closest approach until 2034, so don’t miss it. The pair will meet in the constellation of Leo just to the west of the King star, Regulus.

Try to catch Venus passing right through the Beehive open star cluster in Cancer the crab on the first two nights this month. You will need binoculars since the Beehive cluster will appear very faint and low on the horizon and it will not be completely dark yet. Use this opportunity to learn more about our unique and individual next-door neighbors in space. If we could make them trade places somehow, Mars would warm up and Venus would cool off, and we could have two more living planets in our solar system. Venus has by far the longest day – 243 days long, even longer than its year which is 225 days long. Venus rotates extremely slow, about 4 mph, or walking speed. It also rotates in retrograde, so the sun rises in the west. The earth-sun-Venus system revolves in a perfect resonance. There are five inferior conjunctions for every eight earth years and 13 Venus years.

Remember that we discovered trace amounts of phosphine gas, 20 ppb, in the Venusian atmosphere last fall. This is extremely intriguing since only a living decay process through bacteria or tiny microbes can create this gas. Probably nothing can live on its surface at 900 degrees and constant sulfuric acid rain through its 97% carbon dioxide runaway greenhouse-effect atmosphere, but just maybe something could live higher up in where its atmosphere is less deadly.

Mars is much less extreme, but perhaps even more exciting since we have sent over 50 missions there in the last 50 years including six new missions just this year. Our Perseverance Rover has been on its red surface now for over four months and our Ingenuity helicopter has made many successful flights already. The Chinese have the Zhurong Rover which is now exploring the planet about 1,000 miles away from our rover in Jezero Crater, which is a dry lakebed.

Then keep watching two fascinating points of light, one of which is almost 200 times brighter than the other, as a slender waxing crescent moon will appear just to the right of the pair on Sunday night, July 11, 45 minutes after sunset low in the western sky. The moon will be 12 degrees farther east along the ecliptic and close to Regulus the next evening, when the pair will be just half a degree apart. Then keep watching as Venus continues to climb higher even as Mars sinks lower each evening. Mars will pass very close to Regulus on July 29.

Mercury will reach its greatest elongation west of the sun on the morning of July 4. You can see our first planet low in the east-northeastern sky half an hour before sunrise for the first two weeks this month. Notice that the waning crescent moon will pass close to Mercury in Taurus on the mornings of the July 7 and 8.

Saturn will rise first in Capricorn before 11 p.m., followed by Jupiter about an hour later in Aquarius. They will both rise about two hours earlier, around the end of twilight, by the end of this month. They are now about 20 degrees apart, a big difference from that historic conjunction on the last winter solstice when they were only a tenth of a degree apart, the closest in nearly 800 years. There will be a thrilling series of events with the four large moons of Jupiter on July 24 and 25 visible through a telescope.

Notice that the moon will pass near Saturn and Jupiter 45 minutes before sunrise on the mornings of July 24 through July 26. The moon will be almost perfectly centered between Saturn and Jupiter on July 25.

Pluto is at its best now just to the right of the teaspoon in Sagittarius the teapot. Even finding this dwarf planet in a 10-inch-or-larger telescope will be quite a challenge since it will only reach 14.3 magnitude, nearly 2,000 times dimmer than anything you could see naked eye, which is sixth magnitude. I did manage to see it once through a telescope and I feel lucky to have met its discoverer, Clyde Tombaugh, about 30 years ago. It will reach opposition on July 17 when it will rise right at sunset and not set until sunrise. Pluto is only 1,500 miles in diameter and takes 248 years to orbit the sun once, so it spends nearly 21 years in each constellation and it actually orbits inside the orbit of Neptune for 20 years out of those 248. That last happened 20 years ago.

The New Horizons spacecraft passed within 7,700 miles of its surface six years ago. We discovered a colorful and geologically active world with shifting seas of nitrogen ice, a thin blue atmosphere, broad canyons, mountains of frozen water, a giant glacier only 10 million years old and even ice volcanoes.

The Delta Aquarid meteor shower will peak on July 29. Caused by Comet 96/P Machholz, you can expect about 15 meteors per hour.

JULY HIGHLIGHTS

July 1: Last quarter moon is at 5:11 p.m.

July 5: Earth is at aphelion at 94.5 million miles from the sun.

July 6: In 1687, Isaac Newton published his Principia Mathematica.

July 9: New moon is at 9:17 p.m.

July 12: The moon passes near Venus and Mars.

July 13: Venus and Mars are just half a degree apart.

July 16: The first of 21 fragments of Comet Shoemaker-Levy 9 hit Jupiter today in 1994. I remember watching five of those segments rotate into view as large, earth-sized black marks.

July 20: In 1969, Apollo 11 landed Armstrong and Aldrin on the moon.

July 23: Full moon is at 10:37 p.m. This is also called the Hay or Thunder Moon.

July 24: The moon passes near Saturn this morning.

July 25: The moon passes near Jupiter this morning.

July 29: Mars passes near Regulus this evening. The Delta Aquarid meteor shower peaks.

July 31: Last quarter moon is at 9:16 a.m.

Bernie Reim of Wells is co-director of the Astronomical Society of Northern New England.

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