Larry Wasserman/Matthew Knight/Dave Schleicher/Lowell Observatory
Lowell Observatory astronomer Dr. Larry Wasserman took an image of Comet Nishimura at twilight Wednesday morning using the Lowell Discovery Telescope (4.3 meters in diameter).
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The newly discovered comet will be visible from time to time as it passes near the Earth next week. But finding it requires some know-how.
Japanese space photographer Hideo Nishimura reportedly first observed Comet Nishimura while taking pictures of the night sky in early August. earth sky.
Since then, the object has brightened as it passed through the inner solar system in its orbit around the Sun.
The comet will make its closest approach to Earth on Tuesday and will be within 78 million miles (125 million kilometers), meaning it could be visible for the next five days.
Alan Hale, co-discoverer of Comet Hale-Bopp and founder and president of the Earthrise Institute, said the comet will be closer to the Sun, 21 million miles from its star on September 17. kilometer).
Nishimura’s object rotates once every 430 to 440 years. “This means that the last time Nishimura passed close to the Sun (and may have come close to Earth) was around 1590, before the invention of telescopes,” says Dr. Paul Chodas. , director of NASA’s Near Earth Object Research Center at the Jet Propulsion Laboratory in Pasadena, California, wrote in an email. “I don’t know if it was bright enough to be visible to the naked eye at the time.”
No comet recorded during this time period seems to match Comet Nishimura, Hale said, but it would have had to be fairly bright to see it.
Due to the distance of the comet, it is hardly bright enough to be seen from Earth and it moves close to the horizon, so binoculars are the best way to view it, Chodas said. It also provides the best visibility in dark skies away from city lights.
sky and telescope has a shared chart to help sky watchers find comets.
“If you’re trying to distinguish comets from other objects in the night sky, the comet’s tail always moves away from the sun because sunlight continually pushes out fine dust particles,” said Dave Schleicher, an astronomer at Lowell Observatory. Keep in mind the direction you’re facing,” he said. In Arizona.
And while the comet appears greenish in photographs due to the presence of diatomic carbon, in binoculars it will appear almost colorless or slightly pinkish as sunlight reflects off the dust particles, which are smaller than those of the talcum powder, Schleicher said. he said.
Manuel Romano/Nurfoto/Getty Images
Comet Nishimura will be visible as a pale green dot above L’Aquila, Italy on September 7.
If you live in the northern hemisphere, we recommend finding a spot with a clear view of the east-northeast horizon about 30 minutes before twilight in the morning.can be used date and time Determine when morning twilight (also known as civil twilight) occurs in your area.
“Every day this week, the comet is getting a little closer to the Sun, the time window is getting narrower, and the comet is getting closer to the horizon,” he said. “It’s not easy to see this comet unless you’ve seen a comet before.”
The closer a comet is to the sun or the horizon, the harder it is to see.
On Wednesday, the comet will pass between the Earth and the Sun.
“Theoretically, it could reach the evening sky within a few days after that, but it would still be fairly close to the Sun in the sky and buried in bright twilight,” Hale said. . “You won’t see it until it’s much brighter than expected.”
Given that Comet Nishimura passes very close to the Sun, the heat wave could destroy it.
“If the frozen ice heats up and sublimes into gas, the comet can split up,” Chodas said. “It really depends on the size of the nucleus, but we don’t know because the nucleus is surrounded by a ‘coma’, an atmosphere of gas and dust.”
But given that the comet has already passed by the Sun at least once, and possibly survived many more (although the comet’s age is unknown), Hale and other experts believe that the comet is expected to survive.
“If it survives the transit, it will pass from Earth behind the Sun in early October and appear in the southern morning sky in November,” Hale said. “Although it may remain visible for several months, it will likely be quite faint and will continue to fade as it moves away from the Sun and Earth.”
After that, it will take more than 400 years for the comet to pass near the Earth again.
Even if you miss the chance to see Comet Nishimura, several comets are expected to appear in the night sky within the next 16 months, Hale said.
Comet Pons-Brooks will be closest to the sun in April, and for about a month until then it should be visible to the naked eye in the evening sky, he said. In June, Comet Olbers will pass close to the Sun and can be seen with binoculars. Comet Gassan Atlas, which was discovered in January, will make its closest approach to the sun in late September 2024, and will pass close to the Earth in mid-October 2024, potentially becoming extremely bright.