Look Up! The Southern Delta Aquariids Meteor Shower Is Here

NASA/Bill Dunford
NASA/Bill Dunford

Wake a few hours before sunrise tomorrow and you can start your day with some shooting stars. The Southern Delta Aquariid meteor shower is peaking this week, and while it's not the brightest show of the year, conditions are good and the moonlight is minimal. Provided you live in an area lacking light pollution, you might be in for quite a treat.

Consider this shower to be the big warmup for the Perseids next month. You might even see a Perseid or two tonight (though it's not like they're labeled; just stick with probability when you tell everyone what you saw). So where did these meteors come from, and what's going on up there?

BUZZING THE SUN

Comet Machholz recorded on March 1, 2005
Comet Machholz as recorded on March 1, 2005
NASA/JPL-Caltech/U. Washington/J. Morgenthaler

The Delta Aquariids are suspected to be the debris of 96P/Machholz, a sungrazing comet that orbits the Sun every 5.3 years. Sungrazers are the fighter pilots of the comet world, buzzing perilously close to the face of the Sun as they go about an orbit. Machholz is their Chuck Yeager. The comet's perihelion—that is, its point closest to the Sun in its orbit—is 0.1 astronomical unit. This puts it far closer to the Sun than Mercury, whose perihelion is 0.3 AU. (Earth is 1 AU.) When Machholz is at aphelion—its maximum distance away from the Sun—it reaches 5.9 AU, which is beyond even Jupiter's orbit.

It gets weirder yet. The comet's orbital inclination is 58 degrees. Rather than circle the Sun along the orbital plane of most planets (think of the light bulb and marble-on-wires model of the solar system from grade school), it is swooping up and away pretty dramatically. This adds up to a comet without fear, and as it goes about its orbit, it leaves behind a debris field of dust and sand-sized particles. That's where the Earth comes in. Every year as we travel our orbit, we cross through Machholz's trail, slamming into those particles at tens of thousands of miles per hour. When they burn up in our atmosphere, we get the stunning light show we call a meteor shower.

SEEING IT

As the shower's name implies, its radius—the seeming point of origin in our night sky—is the constellation Aquarius. Don't limit yourself to looking specifically in that area, though; all the sky is a meteor's canvas. You should give your eyes 30 minutes to adjust to the darkness. Bring a blanket and scan about 45 degrees up from the horizon. That's where the most action will begin to be apparent. Good news if you live in the southern hemisphere (or if you live near the equator in the northern hemisphere): You will get the best viewing of anyone on Earth.

The meteors should be visible until sunrise. If you oversleep or the weather is bad, try again tomorrow night. This shower doesn't have a pronounced peak like others, and you have a fair chance of catching something if you stick with it in the days ahead. The next big meteor shower will be the Perseids, which will peak on the night of August 12.

How to See the Full Sturgeon Moon on Thursday

Brook Mitchell, Stringer/Getty Images
Brook Mitchell, Stringer/Getty Images

The full moon of every month has a special nickname. Some—like September's harvest moon, December's cold moon, and May's flower moon—have obvious connections to their seasons, while other names are harder to decode. August's sturgeon moon is an example of the latter. It may not be the prettiest lunar title in The Old Farmer's Almanac, but that doesn't mean the event itself on August 15, 2019 won't be a spectacular sight to behold.

What is a Full Sturgeon Moon?

The first (and normally the only) full moon that occurs in August is called a sturgeon moon. The name may have originated with Native American tribes living around the Great Lakes in the Midwest and Lake Champlain in New England. These bodies of water contain lake sturgeon, a species of freshwater fish that grows up to 6.5 feet in length and can live 55 years or longer. August's full moon was dubbed the sturgeon moon to reflect its harvesting season. This full moon is sometimes called the green corn moon, the grain moon, and the blackberry moon for similar reasons.

When to See the Full Sturgeon Moon

On Thursday, August 15, the full sturgeon moon will be highly visible around sunrise and sunset. The satellite will be 99.9 percent illuminated by the sun when it sets Thursday morning at 5:57 a.m EDT—just nine minutes before dawn. On the West Coast, the setting moon will coincide perfectly with the rising sun at 6:15 a.m. PDT.

If you aren't interested in getting out of bed early to catch the sturgeon moon, wait until Thursday evening to look to the horizon. Twenty-seven minutes after sunset, the full moon will rise on the East Coast at 8:21 p.m. EDT. On the West Coast it rises at 8:10 p.m. PDT, 30 minutes after the sun sets.

The moon generally looks bigger and brighter when it's near the horizon, so twilight and dawn are ideal times to catch the spectacle. But it's worth taking another peek at the sky closer to midnight Thursday night; the Perseid meteor shower is currently active, and though the light of the moon may wash them out, you're most likely to spot a shooting star in the late night and early morning hours.

A Full Harvest Moon Is Coming in September

suerob/iStock via Getty Images
suerob/iStock via Getty Images

The Old Farmer's Almanac lists a special name for every month's full moon, from January's wolf moon to December's cold moon. Even if you're just a casual astronomy fan, you've likely heard the name of September's full moon. The harvest moon is the full moon that falls closest to the fall equinox, and it's associated with festivals celebrating the arrival of autumn. Here's what you need to know before catching the event this year.

What is a harvest moon?

You may have heard that the harvest moon is special because it appears larger and darker in the night sky. This may be true depending on what time of night you look at it, but these features are not unique to the harvest moon.

Throughout the year, the moon rises on average 50 minutes later each night than it did the night before. This window shrinks in the days surrounding the fall equinox. In mid-latitudes, the moon will rise over the horizon only 25 minutes to 30 minutes later night after night. This means the moonrise will occur around sunset several evenings in a row.

So what does this mean for the harvest moon? If you're already watching the sunset and you catch the moonrise at the same time, it will appear bigger than usual thanks to something called the moon illusion. It may also take on an orange-y hue because you're gazing at it through the thick filter of the Earth's atmosphere, which absorbs blue light and projects red light. So if you've only seen the full harvest moon around sunset, you may think it always looks especially big and orange, while in reality, any full moon will look that way when it's just above the horizon.

When to See the Harvest Moon

This year, the harvest moon will be visible the night of Saturday, September 14—about a week before the fall equinox on September 23. The moon will reach its fullest state at 12:33 a.m. ET—but if you're still convinced it's not a true harvest moon without that pumpkin-orange color, you can look for it at moonrise at 7:33 p.m. on September 13.

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