Astro Bob: July celestial highlights for fearless stargazers
Slather on the bug dope as we take a look at the month's finest naked-eye sky sights and events.
Summer nights belong to the bugs. We're the intruders. That's why any foray into the dark means armoring up with bug spray and a coat that will resist the poke of a mosquito's proboscis. I've learned that once I accept this fact and take appropriate steps, it's a breeze to go out and look at the stars.
And not just stars. It's also firefly time. They add so much to the enjoyment of being outside at night. On warm nights, males of multiple species perform their unique light dances above fields and forests hoping to catch the attention of females below. Humans may be clever, but fireflies started using "flashlights" at least 100 million years before Englishman David Misell invented them in 1899 .
The Grand Lineup of planets will be ending early this month as Mercury heads toward conjunction with the sun. That still leaves four planets visible at dawn. If you’re not a morning riser I have good news. Saturn and Jupiter are now far enough from the sun to appear in the evening sky. At mid-month, Saturn rises around 10:30 p.m. local time in Capricornus in the southeast, with Jupiter following at midnight in Pisces. They’ll continue to rise earlier and earlier as July gives way to August.
July is a great time to see the Summer Triangle, a three-sided asterism comprised of three of the season's brightest stars. Face east at nightfall and spy brilliant Vega in Lyra the Harp high in the eastern sky. A little more than two fists held at arm’s length to its lower left you’ll see another bright star. That’s Deneb in Cygnus the Swan. Altair, the brightest star in Aquila the Eagle, shines four fists to the lower right of Deneb. Connect the dots to make a gigantic triangle. On moonless nights, the asterism frames one of the brightest parts of the Milky Way.
Below you'll find a list of cool stuff to see in the July sky. When “a.m.” follows the date, it refers to an event visible in the morning sky after midnight. All times are Central Daylight Time (CDT) unless otherwise noted. I'll be covering some of these events in more depth as individual posts.
July 1-5 a.m. – All five bright planets are still visible at dawn about 45 minutes to an hour before sunrise. Mercury quickly departs the scene after July 5, headed back in the direction of the sun.
July 4 – Earth at aphelion, its farthest from the sun for the year at 94,509,598 miles (152,098,454 km). We’re about 3 million miles closer in January.
July 6 – First quarter moon
July 10-31 – International Space Station (ISS) makes nightly passes across the sky at dusk. For several nights around mid-month, it will be visible on each an every pass — up to five from dusk till dawn! — about every 90 minutes. For pass details, head over to Heavens Above , set your location and click on the ISS link or go to NASA's Spot the Station .
July 13 – Full Buck Moon
July 19 a.m. – Waning gibbous moon passes below Jupiter in the morning sky
July 20 – Last quarter moon
July 21 a.m. – Waning crescent moon passes just to the right (west) of Mars in the small hours before dawn.
July 26 a.m. – Thin, waning crescent passes directly above Venus at dawn low in the eastern sky.
July 28 – New moon
July 30 a.m. – Peak of the Southern Delta Aquariid meteor shower. About a dozen meteors an hour will flash from the constellation Aquarius in the southeastern sky between midnight and the start of morning twilight. Although not a strong shower like next month’s Perseids, it’s a reliable performer.
July 30 – Look for the very young lunar crescent to return to the evening sky low in the west about 45 minutes after sunset.
Did you know that summer is one of the darkest times of the year for stargazing? You might be inclined to think it's winter, but that's not true if it happens to snow where you live. Why? Snow reflects the light of countless street lights, advertising billboards, along with business and home lights back up into the sky. This is especially true of modern LED lights which blaze with a greater intensity compared to previous types of illumination. Many LEDs also emit blue-white light, an especially pernicious color because air scatters and spreads blue light much more efficiently than warmer colors, exacerbating the problem.
All of us can make a difference when it comes to protecting the night sky. Turning off outdoor nights when they're not needed is an easy first step. You can also purchase a motion-activated light that will only turn on if it senses movement near your home or apartment. You'll see more stars, more fireflies and even save a few bucks.
"Astro" Bob King is a freelance writer for the Duluth News Tribune.