[New post] Skywatcher’s Guide: Perseid meteor shower best in years
Trevor Reid posted: "If you've never been much of a skywatcher, these August nights will give you all kinds of good reasons to get into the habit. For starters, the annual Perseid meteor shower will be as good as it gets when it peaks overnight Aug. 12-13. The moon wil" Greeley Tribune
If you've never been much of a skywatcher, these August nights will give you all kinds of good reasons to get into the habit.
Daniel Zantzinger (Skywatcher's Guide)
For starters, the annual Perseid meteor shower will be as good as it gets when it peaks overnight Aug. 12-13. The moon will do little to interfere, not rising until 3:11 a.m. on the 13th, and shining a mere 8% illuminated when it does. Try to get as far away as you can from urban light pollution for the darkest skies to see the most meteors. For guidance, visit the interactive map at lightpollutionmap.info.
To find the Perseids, you'll need to locate its radiant, the general area where the streaks of light appear to originate. At 9 p.m., look northeast to find the W-shaped Constellation Cassiopeia, and then directly beneath it for the head stars of just-rising Constellation Perseus. This is your radiant.
Perseid meteors are sand- to pebble-size remnants of the dusty, rocky nucleus of the 16 mile (26 km) diameter Comet Swift-Tuttle. As the "dirty snowball" passes close to the sun on its 133-year orbit, meteoroids and dust come loose, the frozen gasses sublimate and form the comet's coma and tail.
As it roars through the inner solar system, the comet leaves a long trail of debris, some of which crosses Earth's path. The meteoroids become meteors when they collide with Earth's high atmosphere at 124,274 mph (200,000 km/h). The impact and deceleration erode the meteoroids as they flash through a bright trail streak of energized gas. Meteors are usually less than 3 feet (1m) wide, but can extend for tens of miles.
Since the Perseids peak on a weekend, you might want to break the evening up into two parts; one with the youngsters who have bedtime schedules and another for skywatchers off the leash. The radiant reaches 21 degrees above the horizon by 11 p.m. Saturday, not optimal but still high enough to keep the kids engaged. Keep in mind that this shower is active from July 16 until Aug. 24, so watch the northeast sky the nights on either side of the peak.
The real action begins in the morning hours of the 13 th . The radiant increases in altitude between 6 to 8 degrees each hour, so by 5:05 a.m., the start of nautical twilight, the Perseids are at a staggering 65 degrees above the horizon, very much overhead. The higher that the radiant is, the more meteors are visible. Depending upon conditions, the zenithal hourly rate (ZHR) can be 60 meteors or more per hour, admittedly less of a shower and more like a trickle. That said, large comets like Swift-Tuttle are more prone to smoky, long train fireball bolides that can explode, so stay alert.
"If you plan on photographing the event, use a tripod-mounted camera at ISO 1600 and equipped with an intervalometer set to take successive 30-second exposures. My default lens is a 16-35-mm zoom dialed in to about 20-mm, with the aperture wide open at f/2.8," according to Bob King, contributing editor in the August 2023 issue of Sky & Telescope magazine.
Perseus, a Greek hero with a dubious record, is represented by an asterism with a triangular head, boxy body, two stick arms and two long legs. The hero's checkered past is somewhat redeemed in telescopes by the presence of many open star clusters, multiple nebulae including the Dumbbell Nebula and myriad galaxies and galactic clusters such as Abell 426, the closest such cluster to the solar system.
Constellation Sagittarius, the centaur archer Chiron, culminates 9 p.m. Aug. 20 and reaches its highest point of the year when it strikes the north/south meridian. Along with Constellation Scorpius, several bands of the Milky Way galaxy intersect due south and is famous for its various celestial entities. Use image stabilizing binoculars or a telescope to revel in these glorious August nights' spectacles.
The first occultation — eclipse — of the scorpion's heart star by the moon since 2018 occurs Aug. 24. Look due south before 8 p.m. to find Scorpius's red giant Antares, in fact a double star with a +5.4 magnitude companion, glowing near a 57 percent illuminated moon low in the southwest. At 8:01 p.m., the dark limb of the moon covers the secondary star first and then the magnitude +1.0 primary star moments later. The occultation ends at 9:11 p.m. as Antares reemerges from behind the moon's bright limb.
Views of Mars become increasingly rarified as it gets lost in the solar glare as the month progresses. In fact, Aug. 18 will be the very last time that you can observe the god of war until next year as it heads to the other side of the sun before gradually returning to March's morning skies.
Summer's midpoint is Aug. 7.
Two full moons this August. The moon is full 12:31 p.m. Aug. 1, and is called the Full Sturgeon Moon, and again 7:35 p.m. Aug. 30, known as a Blue Moon. This moon will be the closest and visually the largest of the year, referred to by astronomers as a "perigean full moon."
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