Philadelphia-area stargazers are preparing for a double celestial treat this week with a rare comet and a massive moon set to shine in the night sky.
“This could be a once-in-a-lifetime experience,” Derek Betts, a senior astronomer at the Franklin Institute, said of Comet Tsuchinshan-Atlas’s appearance over the Philadelphia area this week. “So, bring some friends with you and enjoy the view.”
The comet shines brighter just as the supermoon Hunter’s Moon shines brighter than usual.
With all the excitement in the night sky, we’ve got your guide to catching a glimpse of Comet Tsuchenshan-Atlas and the supermoon. Here are answers to your questions.
Let’s talk about Tsuchenshan-Atlas first.
What is a comet?
“Comets are frozen remains from the formation of the solar system, consisting of dust, rocks and ice,” NASA says. Comets are “snowballs of frozen gases, rocks and dust that orbit the Sun.”
NASA says comets “range from a few miles to tens of miles across, but when they orbit close to the sun, they heat up and spew out gases and dust in a glowing head that can be larger than a planet.” “This material forms a tail that extends millions of miles.”
Basically what you can see is the tail of hot debris.
There is no shortage of comets waiting to be discovered.
“There are likely billions of comets orbiting our Sun in the Kuiper Belt and even the distant Oort Cloud,” NASA says.
“Comets are more fragile than people might realize, thanks to the effects of their passage close to the Sun on internal water ice and volatiles like carbon monoxide and carbon dioxide,” said NASA astronomer Bill Cook, who leads NASA’s Meteorite Environment Office. Marshall Space Flight Center in Huntsville, Alabama.
NASA wrote in a Watch the Skies blog post:
The brightness of comets is measured on the same scale we use for stars, a scale that has been in use since about 150 BC, when it was devised by the ancient scientist Hipparchus and improved by the astronomer Ptolemy. Stellar magnitude is measured on a logarithmic scale, making a star with a magnitude of 1 exactly 100 times brighter than a star with a magnitude of 6. The lower the number, the brighter the object becomes, making it more likely to be seen clearly, either with a telescope or with the naked eye.
“Normally, a comet would have to reach a magnitude of -6 to -10 to be seen in daylight,” Cook said. “This is extremely rare.”
There is no comet more famous than Halley’s Comet, which orbits the Earth every 75 to 76 years. NASA says: “Hale is the only known short-period comet that can be regularly seen with the naked eye from Earth, and the only naked-eye comet that can appear twice in a human’s lifetime.”
Where did Comet Tsuchenshan-Atlas come from and how did it get its name?
This comet is much rarer than Halley’s Comet, and may not return again, according to astronomers.
“Comet Oort Cloud, named C/2023 A3 Tuchinshan-ATLAS, was discovered in 2023 approaching the inner solar system in its highly elliptical orbit for the first time in documented human history,” NASA wrote in a post on the Watch the Skies blog. “It was identified by observers at China’s Zouchenshan Observatory – or ‘Purple Mountain’ – and the ATLAS (Terrestrial Asteroid Impact Alert System) telescope in South Africa. The comet has been officially named in honor of both observatories.”
The comet will likely have been in its orbit for “more than 80,000 years,” according to Franklin Institute chief astronomer Derek Bates.
This may be a one-time global event, as NASA updated its forecast earlier this week: “The comet’s path may knock it out of the solar system completely.”
When will the comet be visible?
NASA’s Earth Observatory said the comet came within about 44 million miles of Earth on October 12, 2024.
Tsuchinshan-Atlas first appeared low in the west just after sunset in the early night sky that Saturday, Bates said in an Instagram clip. On the following evenings, it rose into the sky and became clearer.
“At peak visibility in the Northern Hemisphere, the brightness of Tsuchinshan-Atlas is estimated to be between 2 and 4,” Watch the Skies said. “By comparison, the brightest star visible in the night sky, Sirius, has a magnitude of -1.46. At its brightest, the Sun’s reflection from Venus is -4. The International Space Station sometimes achieves a relative brightness of -6.”
As of October 15, the comet had a magnitude of 3.3, NASA said.
With the sun setting at 6:19 p.m. on Wednesday, the best time to go out is between 6:50 p.m. and 7 p.m., NBC10 First Alert Weather meteorologist Bill Henley said. “Look toward the western horizon, where the comet will set.”
Astronomers said the comet will continue to dim as it moves away from the sun each night and should be out of sight by early November.
“And savor the view,” Cook advised.
What are the best conditions for viewing a comet?
“The comet’s head – made up of the nucleus and coma – along with the tail should be visible again under a clear, dark sky,” Bates said.
Grab the compass to get your bearings.
“Choose a dark observation point immediately after complete darkness, as Cook recommended,” NASA said. “Looking to the southwest, approximately 10 degrees above the horizon, identify the constellations Sagittarius and Scorpio. Tsuchinchan-Atlas should be visible between them. By October 14, the comet may still be visible at the midpoint between the bright star Arcturus and Venus.”
“Stars and comets will shine brighter against the background of dark skies, making this a near-perfect opportunity to see a comet once every 80,000 years,” Henley said.
Bates recommends grabbing binoculars to “follow the comet.”
“For the best view, try to find a place away from city lights to reduce light pollution,” Henley agrees. “And while the comet may be visible to the naked eye, binoculars or a small telescope will give you a clearer, more detailed view, especially if you want to see its tail.” “
Now to this giant supermoon.
“Watch your back,” Henley said. “In addition to the comet, you also want to check how nearly full Hunter’s Moon is rising in the eastern sky. It will be the brightest supermoon of the year. Although the moon won’t be fully lit until Thursday morning, it will still be.” It’s going to be a great spectacle Thursday night, happy watching!”
What is a supermoon?
“The term ‘supermoon’ was coined in 1979 and is often used to describe what astronomers call a perigee full moon: a full moon that occurs near or at the time when the moon is at its closest point in its orbit around Earth,” NASA wrote.
NASA said: “A supermoon occurs when the moon’s orbit is closest (perigee) to Earth at the same time that the moon is full.”
Basically, it appears to be a larger full moon than usual.
Why is the supermoon in October so great?
Just all the names of this supermoon make it special. “The next full moon is the supermoon; the hunter’s moon; the traveling moon, the dying grass moon, or the sanguine moon or the blood moon; the beginning of Sukkot; Sharad Purnima, Kumara Purnima, Kujagari Purnima, Navana Purnima, Kujagrat Purnima, or Kumudi,” wrote Gordon Johnston, Watcher of the Sky. At NASA, the end of the Vasa and Pavarana Festival, and the end of the Phaung Daw U Pagoda Festival.
The third supermoon of 2024 will reach a distance of about 222,055 miles Wednesday night, making it appear larger and brighter than the previous supermoons in August and September.
“Scientists point out that only the most careful observers can discern subtle differences,” the Associated Press reported. “It’s easier to detect a change in brightness – a supermoon can be 30% brighter than average.”
What is the best time to view the October supermoon?
NASA said that the moon will officially become full on Thursday morning (October 17, 2024) at 7:26 a.m. Eastern time. However, the moon will be a “supermoon,” reaching perigee at 8:48 PM ET on Wednesday.
The best times to see it in all its glory are Wednesday night through Thursday morning before sunrise. The moon will rise in the east at 5:51 p.m. ET on Wednesday, October 16, Henley said.
However, “it should look full for about three days at this time, from Tuesday evening through Friday morning,” Johnston said.
Can the moon actually deter a comet?
Moonlight will erase some of the comet’s visibility, Cook told The Associated Press.
“Most astronomers hate the full moon because its bright light spoils observations of other objects. So it’s a bit difficult for us to wax poetic about this even if it is the largest supermoon of 2024,” he said in an email.
The biggest question: Will the weather over the Philadelphia area cooperate for the double celestial feature?
Simple answer: Yes!
“Over the next few evenings, the weather will be almost perfect for a rare glimpse of the comet that has been lighting up the night sky,” said meteorologist Bill Henley. “In the Philadelphia area, a large area of high pressure is building up, bringing us clear skies and cool nights. This will also reduce atmospheric moisture and particles, giving us a clearer, sharper view of the night sky.”
“Temperatures will drop into the 40s by the time the comet dips below the horizon at 8:32 p.m. on Wednesday, October 16, 2024, so be sure to dress warmly,” Henley said.
Don’t worry if you missed seeing the comet Wednesday night, as Henley said clear skies will continue over the next few days.
Enjoy!
