July, which gets its name from Julius Caesar, marks the first full month of summer for us in the northern hemisphere. There will be many interesting highlights to catch under the skies of warm summer nights, so make sure you get outside and observe some of them for yourselves.

These include our next-door neighboring planets, Mars and Venus, putting on a show each evening as they will approach to within less than 4 degrees on the first of the month. Venus reaches its greatest brilliancy of -4.7 on July 7. It will be about 200 times brighter than Mars, which is only 1.8 magnitude. Mercury joins the show late in the month, getting as close as 5.5 degrees to Venus on the 25th. Our first planet, Mercury, will be about 6 times brighter than Mars.

Saturn begins the month rising before midnight and ends the month rising before 10 p.m. on way to its opposition on Aug. 27, when it will rise at sunset. Then Jupiter is not far behind, rising around 2 a.m. on July 1 and at midnight by the end of the month on the way to its opposition on Nov. 3. Our largest and brightest asteroid, Ceres, at 600 miles across, will be passing through Virgo, shining at 8.8 magnitude. Then you can see Comet 237P/LINEAR carving its way through Aquila this month at 11th magnitude if you have a good telescope. A whole parade of five much brighter comets is on the way soon, starting with Comet Lemmon at 8th magnitude next month, then Comet 103P/Hartley 2 at 7th magnitude in November, and possibly three binocular comets by the spring.

To top all of that off, you have three meteor showers to look forward to this month after a long but expected drought of good meteor showers so far this year. The best one will be the July 30 Delta Aquarids, peaking at about 15 meteors per hour. Then there are two lesser known and more minor ones at only 5 meteors per hour, just above the background rate of stray meteors from anywhere in the sky of 2 to 3 per hour. These are the July 28 Pisces Austrinids and the July 27 Alpha Capricornids, caused by Comet NEAT.

Venus was gaining on Mars all of last month but could never quite catch it. Watch them play tag with each other in the constellation of Leo the lion all month. Venus was at greatest eastern elongation from the sun and exactly half lit last month and now it is getting thinner and closer to us each day, reaching its greatest brilliancy for the year on the 7th at magnitude minus 4.7. We will lose our sister planet to the western evening twilight by early next month.

Saturn is slowly getting a little brighter and closer each evening, gaining a half magnitude of brightness this month. It is in Aquarius the Water-bearer now, where it will hang out for two years after spending the last two years in Capricorn. It spends a little over two years in each of the 12 zodiac constellations because it takes 29 years to orbit the sun. Saturn already started its retrograde or westward motion against the background of stars last month on June 17, and it will return to its normal, direct, eastward motion on Nov. 4. Opposition always marks the exact midpoint of this retrograde loop for each of the superior planets.

Its spectacular ring system is now only tilted about 7 or 8 degrees relative to us, and it is gradually getting less and less tilted so that our view of them will be directly edge-on by 2025. That happens every 29 years, since that is its orbital period. I remember when the rings completely disappeared for a while in 1996 and Saturn looked more like Jupiter with no rings.

NASA is planning a $5 billion mission called Orbilander to the sixth largest moon of Saturn, Enceladus, at 300 miles in diameter. We just found 62 new moons of Saturn, so its total is now 145, passing Jupiter’s 95 moons. We already knew that Enceladus has a warm salty ocean with organic matter just below its surface, since it is spewing geysers of this water into space from its south pole, forming a much wider diffuse watery ring around Saturn, well beyond its visible rings of rock and ice. They just found another critical ingredient in these plumes, phosphorus. Along with carbon, hydrogen, oxygen, nitrogen and sulfur, these five common elements make up 98% of living matter on Earth, so the prospects for life in the oceans under Enceladus just went way up.

This mission will not launch until 2038, about the time we will be walking around on Mars. Then it will be taking a slower approach to the ringed planet so it can use a smaller rocket to launch and will not get there until 2050. Orbilander should orbit the moon for 200 days, taking samples of these plumes of rich ocean water, and then it will land on its south pole for two years to get close up pictures and samples to see if there really is life there and how it might have formed and evolved.

Jupiter is now in Aries the Ram, still traveling in its direct eastward motion until Sept. 4. The king of the planets is also getting a little larger and closer and brighter each night, along with Saturn, as we are catching up with these two giants in our orbits. There will be several transits of its large moons, Io and Ganymede, visible this month in a telescope.

The best of the three meteor showers this month will be the Delta Aquarids, which peak on July 30 but last from the middle of July to the middle of August. You will also see some early Perseid meteors late this month if you look for them. The Perseids always peak on Aug. 11-12.

JULY HIGHLIGHTS

July 3: Full moon is at 7:39 a.m. This is also known as the Hay or Thunder moon.

July 5: In 1687, Isaac Newton published his “Principia,” describing the laws of universal gravitation and many other principles of math and physics.

July 6: Earth is at aphelion, or farthest from the sun, today at 94.5 million miles. We get as close as 91.5 million miles in early January and we average 93 million miles, which is one astronomical unit. The moon passes just 3 degrees south of Saturn tonight.

July 9: Last quarter moon is at 9:48 p.m.

July 10: Mars passes less than 1 degree north of Regulus on this morning.

July 11: The moon passes 2 degrees north of Jupiter on this evening.

July 17: New moon is at 2:32 p.m.

July 20: Humans first landed on the moon on this day in 1969. We last landed there in December 1972. Now we will go back there with humans landing there again on a regular basis around 2025 with the Artemis missions, the mythological twin sister of Apollo. The moon passes 8 degrees north of Venus and 3 degrees north of Mars tonight.

July 23: Vera Rubin was born in 1928. She first discovered the galaxy rotation problem that led to dark matter as the explanation, first theorized by Fritz Zwicky in the 1930s.

July 25: First quarter moon is at 6:07 p.m.

July 26: Mercury passes 5 degrees north of Venus.

July 28: Mercury passes just 0.1 degrees south of Regulus.

July 30: The southern Delta Aquarid meteor shower peaks on this evening.

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

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