See the moon cross the Pleiades for the last time this year on July 20
If you live anywhere in the contiguous U.S. or Canada, and clear skies are forecast for early Sunday morning, July 20, then be sure to step outside after midnight and before the first light of dawn. Look low in the east-northeast sky for a slender crescent moon just four days before new phase and 23% illuminated, gracefully approaching the Pleiades star cluster. This will mark the third and final lunar occultation of the Pleiades in 2025, promising a very beautiful scene in steadily held binoculars or a small telescope.
Earlier this year, there were two other moon-Pleiades encounters. On the evening of January 9th, an 82%waxing gibbous moon temporarily hid the Pleiades for parts of the U.S., Canada and Central America and then during the overnight hours of February 5-6, a 61% waxing gibbous moon passed in front of the cluster. If you caught one, or both of the first two events (or if you didn't), make a note on your calendar to watch this final moon-Pleiades rendezvous of the year.
In this upcoming case, you will either have to stay up through the night (to await moonrise, which will occur around 1:00 a.m. local daylight time) or set your alarm for the predawn morning hours.
In addition, since the moon will be a lovely waning crescent, as opposed to a waxing gibbous in January and February, stars will disappear first along the bright lunar crescent. You'll need at least a small telescope, for binoculars probably won't be enough for following stars in the final minutes or seconds as the moon's glare, sunlit edge creeps up to them. But practically any telescope will magnify enough to do the trick. Use 50x magnification, perhaps more if your scope has a solid mount that allows easy tracking.
Stars will reappear about an hour later from behind the moon's dark limb in dramatic fashion: appearing to suddenly "pop-on" as if someone threw a switch. Here, binoculars should do fine, especially if you mount them on a tripod, provided you're watching at exactly the right moment.
In Canada's Maritime Provinces and the northeastern U.S., advancing morning twilight will be an issue, since the eastern sky will be brightening as the moon approaches the Pleiades. As a result, the disappearance of some stars will not be visible because the sky will be too bright. Nonetheless, the view in binoculars of the crescent moon sitting to the upper right of the star cluster will still make for a very pretty sight.
Farther west, the sky will be darker, but the moon and the Pleiades will be lower. This will be especially true for the far-western states and the Canadian province of British Columbia; therefore, a clear and unobstructed view toward the east-northeast is recommended.
Below are two timetables giving local circumstances for the disappearance and reappearance of the four brightest members of the Pleiades that will be occulted. The information is based in part on data generated by the International Occultation Timers Association (IOTA) and is valid for fourteen U.S., two Canadian and one Mexican city. Keep in mind, however, that many other stars not listed here will also be occulted.
If the disappearance or reappearance of a star takes place during dawn twilight, the time is provided in italic font. Also, take note that if the disappearance or reappearance of a star occurs near or soon after the start of civil twilight (roughly 40 minutes before sunrise), it is assumed that the sky would probably be too bright to easily see it. In addition, the moon might miss the star entirely. In both such cases, the time is omitted. All times are in local civil time.
Location
Electra
Alcyone
Atlas
Maia
Los Angeles
——
2:21 a.m.
——
——
Seattle
2:03 am.
2:39 a.m.
3:16 a.m.
——
Tucson
——
2:18 a.m.
——
2:07 a.m.
Denver
2:35 a.m.
3:27 a.m.
——
——
Helena
2:52 a.m.
3:36 a.m.
4:19 a.m.
——
Monterrey
2:13 a.m.
3:28 a.m.
——
2:44 a.m.
Austin
3:17 a.m.
4:26 a.m.
——
3:51 a.m.
Kansas City
3:30 a.m.
4:31 a.m.
——
4:10 a.m.
Winnipeg
3:50 a.m.
4:43 a.m.
——
—-
N. Orleans
3:16 a.m.
——
——
3:48 a.m.
Chicago
3:33 a.m.
4:41 a.m.
——
4:12 a.m.
Atlanta
4:21 a.m.
——
——
4:54 a.m.
Miami
4:15 a.m.
——
——
4:42 a.m.
Washington
4:30 a.m.
——
——
5:05 a.m.
New York
4:35 a.m.
——
——
——
Boston
4:39 a.m.
——
——
——
Montreal
4:42 a.m.
——
——
——
Location
Electra
Alcyone
Atlas
Maia
Los Angeles
2:15 a.m.
3:10 a.m.
——
——
Seattle
2:22 a.m.
3:31 a.m.
4:01 a.m.
——
Tucson
2:13 a.m.
3:04 a.m.
——
2:27 a.m.
Denver
3:21 a.m.
4:19 a.m.
——
——
Helena
3:26 a.m.
4:31 a.m.
4:56 a.m.
——
Monterrey
3:05 a.m.
3:35 a.m.
——
3:33 a.m.
Austin
4:11 a.m.
4:51 a.m.
——
4:38 a.m.
Kansas City
4:24 a.m.
5:16 a.m.
——
4:46 a.m.
Winnipeg
4:37 a.m.
——
——
——
N. Orleans
4:11 a.m.
——
——
4:43 a.m.
Chicago
4:31 a.m.
——
——
4:57 a.m.
Atlanta
5:18 a.m.
——
——
5:52 a.m.
Miami
5:03 a.m.
——
——
5:44 a.m.
Washington
—-
——
——
——
New York
——
——
——
——
Boston
——
——
——
——
Montreal
——
——
——
——
Specific times and zones of visibility
Courtesy of IOTA, detailed prediction pages are available for each of the four brightest stars — Alcyone, Atlas, Electra, and Maia. These include Universal Time (UT) disappearance and reappearance data, as well as Mercator maps showing where each occultation will be visible.
For example, from St. Louis, Missouri (in Central Daylight Time, UTC–5), Maia will disappear at 4:06 a.m. CDT and reappear at 4:51 a.m. CDT. At the moment of reappearance, the sun will be about 11 degrees below the horizon, meaning Maia should reappear in a twilight sky.
TOP TELESCOPE PICK
Want to see the moon and Pleiades together? The Celestron NexStar 8SE is ideal for beginners wanting quality, reliable and quick views of celestial objects. For a more in-depth look at our Celestron NexStar 8SE review.
In addition to the timetable, a world map (Mercator projection) is provided, showing the region where the occultation will be visible. The boundaries are in different colors. The Cyan boundaries show the curves of the occultation disappearance or reappearance at moonrise or moonset. A continuous white line marks the nighttime northern and southern limits of the occultation. A continuous blue line denotes the occultation limits occurring during twilight, while a dotted red line depicts the occultation limits occurring in daylight.
For Alcyone, the occultation takes place over much of the western U.S. For Atlas, visibility occurs over the northwest U.S., western Canada and Alaska. For Electra, visibility will be over much of the U.S. and Canada, while the occultation of Maia will be visible primarily over the central and southern U.S. and Mexico.
Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky and Telescope and other publications.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
CBS News
4 hours ago
- CBS News
More than 20% of NASA's workforce requests to leave agency
Nearly 4,000 employees, or more than 20% of NASA's workforce, have applied to leave the agency, NASA confirmed to CBS News Friday. About 3,870 employees have applied to depart NASA over two rounds through the Trump administration's deferred resignation program, NASA disclosed. The deadline for applications to the program is midnight Friday. With those deferred resignations, NASA's civil servant workforce would shrink from about 18,000 to 14,000 personnel. This figure also includes about 500 employees who were lost through normal attrition, the agency said. "Safety remains a top priority for our agency as we balance the need to become a more streamlined and more efficient organization and work to ensure we remain fully capable of pursuing a Golden Era of exploration and innovation, including to the Moon and Mars," NASA spokesperson Cheryl Warner said in a statement. According to NASA, about 870 employees applied to leave during the first round of the Deferred Resignation Program, and about 3,000 employees during the second round. The deferred resignation program was a buyout program introduced across the federal government by the White House's Department of Government Efficiency at the onset of the Trump administration in an effort to slash costs and reduce the size of the federal workforce. A White House budget proposal issued in May would see NASA's funding cut by about 25% for fiscal year 2026, from about $24 billion to $18 billion. NASA has also been roiled by a leadership crisis in recent months. In December, President Trump nominated billionaire private astronaut Jared Isaacman, a friend of former DOGE head Elon Musk, to serve as NASA's next administrator. Musk's SpaceX has several NASA contracts. However, in late May, Mr. Trump pulled Isaacman's nomination just ahead of the Senate confirmation vote, which was followed days later by a public fallout between Mr. Trump and Musk. Earlier this month, the president announced that Transportation Secretary Sean Duffy would temporarily lead the agency. Miles Doran contributed to this report.
Yahoo
5 hours ago
- Yahoo
Interstellar Meteors Hit Earth All the Time but Still Elude Astronomers
Astronomers think small space rocks from beyond our solar system routinely strike Earth—but proving it isn't easy Aliens are visiting our solar system. Not little green men, sadly, but natural alien objects—cosmic bodies such as comets and asteroids born elsewhere in the galaxy that zip by the sun as they drift through the Milky Way. They're not so much visiting as just passing through. Though these objects were speculated to exist for a long time, we didn't know they were out there for sure until October 2017, when astronomers noticed a small body moving through space at exceptionally high speed. Observations over just a few nights showed it was moving far too quickly to be orbiting the sun and thus must have come from some other star. It was our first known interstellar visitor. [Sign up for Today in Science, a free daily newsletter] Eventually designated 1I/'Oumuamua, it was 30 million kilometers from Earth and already outward bound from the solar system when it was discovered, offering scant time for follow-up studies. But then, less than two years later, a second such object was found, also moving far faster than usual. 2I/Borisov turned out to be a comet very similar to those we're familiar with, except for its trajectory, which clearly showed it came from interstellar space. And now a third such alien body is barreling through the solar system: 3I/ATLAS, moving so rapidly its path is barely bent at all by the sun's gravity as it zooms past. In science, one is an anomaly and two might be coincidence, but three is a trend. Clearly, objects like this are passing by on the regular. Roughly speaking, there could be ones 100 meters in size or larger passing through the inner solar system at any time. Given their speed and intrinsic faintness, though, they're difficult to detect. We also know that when it comes to things such as asteroids and comets, nature tends to make many more smaller ones than bigger ones. In our own solar system, for example, only a couple of dozen main-belt asteroids are bigger than 200 km wide, but more than a million are 1 km across or larger. This generalization should hold for interstellar interlopers as well. For every kilometer-scale one that we see, there should be far more that are smaller. In fact, there could be millions of sand-grain-sized alien objects whizzing past us right now. And we already know that they're out there: in 2014 astronomers announced they had found seven grains of cosmic dust brought down to Earth from the Stardust space probe, which was designed to catch material ejected from a comet. Also, embedded in some meteorites that have hit Earth are tiny bits of material, called presolar grains, that are so old they actually formed around other stars. They got here after being blown across the void of space into the collapsing cloud of gas and dust that formed the sun and planets 4.6 billion years ago. Larger material could be ejected from an alien planetary system if it's given a gravitational assist when passing by a planet there, or it could be torn away from its parent star by another star passing closely to that system. So it seems certain interstellar jetsam would occasionally hit our planet. Earth is a small target, but with so many galactic bullets, you'd think some would actually find their way to our planetary bull's-eye. The problem is detecting them. Every day Earth is hit by very roughly 100 tons of locally grown interplanetary debris—material ejected from asteroids and comets native to our solar system—which translates into billions of tiny specks zipping across our sky daily. Detecting the tiny fraction that have an interstellar origin is tough. And the difficulty is not just in the sheer numbers. It's in tracing the trajectories of that small handful across the sky back up into space to calculate their orbits. When an object such as a planet or an asteroid orbits the sun, we say it's gravitationally bound to our star. That orbit in general is an ellipse, an oval shape. These can be defined mathematically, with the key factor being the eccentricity: how much the ellipse deviates form a circle. A perfect circle has an eccentricity of 0, and the higher the eccentricity, the more elliptical the orbit, up to a value of just under 1. An orbit with an eccentricity of 0.99, say, is extremely elongated; you might find that an object dropping down very close to the sun from the outer solar system has an eccentricity that high. It's possible to have an eccentricity higher than 1 as well. That kind of trajectory is called hyperbolic—named after the mathematical curve, not because it's exaggeratedly over-the-top—and an object on this path is not bound to the sun gravitationally. Once it's heading out, it's gone forever. It ain't coming back. This is how we know 'Oumuamua, Borisov and ATLAS are from interstellar space; each has an eccentricity greater than 1—'Oumuamua's is about 1.2 and Borisov's 3.4, which is quite high, but ATLAS has them both beat with an astonishing eccentricity of 6.2. That's extraordinarily high and also indicates it's hauling asteroid (or, more accurately, it's not comet back). Do we see any meteors with eccentricities like these? If the exact path of a meteoroid (the term for the solid bit that burns up in the air and becomes a meteor) through Earth's atmosphere can be determined, that can be backtracked up into space, allowing the object's trajectory, including its eccentricity, to be calculated. This can be done with multiple sky cameras set up in various locations; if a meteor streaks across their field of view, the multiple vantages can allow astronomers to triangulate on the rock and measure its path. There are quite a few such camera networks. It's actually difficult getting good enough data to determine solid orbits for meteoroids, though. Many do have eccentricities very close to 1; these likely come from long-period comets that originate out past Neptune. NASA's Jet Propulsion Laboratory maintains a database of bright fireballs—exceptionally luminous meteors—at the Center for Near-Earth Object Studies (CNEOS). The earliest recorded meteors in the database date back to 1988, so there is a rich hunting ground in the data. Are any of the meteors listed hyperbolic? Unfortunately, no. At least, not unambiguously—there have been false positives but nothing clear-cut. Additionally, a study from 2020 looked at 160,000 measurements by the Canadian Meteor Orbit Radar covering 7.5 years. The researchers found just five potential interstellar meteors. The results aren't quite statistically strong enough to claim detections for sure, but they're very compelling. What we need are more eyes on the sky, more meteor camera networks that can catch as many of these pieces of cosmic ejecta burning up in our atmosphere as possible. It's a numbers game: the more we see, the more likely we'll see some that are not from around here. The science would be, well, stellar: these meteors can tell us a lot about the environments around other stars, the ways they formed and perhaps even the stars they come from. We're getting physical samples from the greater galaxy for free. We should really try to catch them. Hat tip to planetary scientist Michele Bannister for the link to the CNEOS article. Solve the daily Crossword
Yahoo
5 hours ago
- Yahoo
Yellowstone is hiding more than 80,000 earthquakes below its surface
Researchers at the University of Western Ontario have uncovered over 86,000 earthquakes moving in chaotic swarms through rough, young fault lines beneath Yellowstone. The findings are significantly higher than the previously known number of earthquakes in the area. The study appears in the journal Science Advances. 'With these new insights, we're getting closer to decoding Earth's volcanic heartbeat and improving how we predict and manage volcanic and geothermal hazards,' the authors write in a statement. Researchers used a machine learning algorithm to process and identify earthquake signals within 15 years of seismic data from the Yellowstone caldera, which was formed by a volcanic eruption more than 630,000 years ago. Previously, researchers manually inspected earthquake data—a process that was both expensive and time-consuming. By automating the detection and classification of seismic events, machine learning allowed the Western team to uncover many more earthquakes in the dataset, revealing ten times more seismic activity than previously known. That brings the historical catalogue for the Yellowstone caldera up to 86,276 earthquakes between 2008 and 2022 and paints a much clearer picture of what's going on beneath the surface, researchers say. "To a large extent, there is no systematic understanding of how one earthquake triggers another in a swarm. We can only indirectly measure space and time between events," Western engineering professor Bing Li, one of the study's authors, says. "But now, we have a far more robust catalogue of seismic activity under the Yellowstone caldera, and we can apply statistical methods that help us quantify and find new swarms that we haven't seen before, study them, and see what we can learn from them." Header image: File photo of Yellowstone's Grand Prismatic Spring. (U.S. Geological Survey)
