Comets are traditionally named by or after the person or observatory that discovered them. - PHOTO: COURTESY OF AKASH ANANDH
SINGAPORE (The Straits Times/ANN): Stargazers and astronomy enthusiasts can look to the skies to catch a rare comet from this weekend without using binoculars or telescopes.
Astronomical societies in Singapore say the Comet C/2023 A3 (Tsuchinshan–Atlas) – which has already been spotted in Singapore’s skies in the past few weeks during the hour before sunrise – will be most visible in the western part of the island from Oct 11 to Oct 22 with minimal light pollution.
According to the Science Centre Observatory (SCOB), the comet is predicted to be at its brightest on Oct 11. However, SCOB said it will be hard to see the comet as it is expected to appear quite close to the Sun on Oct 11, and sunlight may mask the light reflecting off the comet.
It added that the comet will most likely be visible between Oct 14 and Oct 20, and there is a strong possibility that observers can see the comet with the naked eye.
“Observers would have the best chance of seeing Comet C/2023 A3 on Oct 14, in the western sky just after sunset,” the SCOB said. However, the visibility of the comet depends on many factors such as the weather, sky conditions and the comet’s own behaviour, it added.
Dr Koh Wee Ming, assistant honorary secretary of The Astronomical Society of Singapore (Tasos), said the best window for viewing the comet will likely be between Oct 13 and Oct 22, as it will be visible directly in the west after sunset.
The NTU Astronomical Society said a good viewing time would be around 7.30pm, about 20 to 30 minutes after sunset.
Stargazers can observe the comet as it sets later than the Sun in the west. As the distance between the comet and the Sun increases each day, it will remain visible in the sky for a longer period before setting, said Dr Koh. However, as the comet moves farther from Earth, it will become dimmer and harder to spot due to reduced sunlight reflecting off its surface and the increasing distance from Earth, he added.
This image of Comet C/2023 A3 was taken on Oct 1 at 6:22am, from a carpark in Toh Guan. - PHOTO: COURTESY OF ALBERT LIM, ASTRO SCIENTIFIC CENTRE
To view the comet, observers should seek locations with unobstructed views of the western sky with as little light pollution as possible, said SCOB, which will be hosting a virtual viewing session on Oct 17 from 7pm to 8pm, if the weather permits.
The live stream from a telescope in the observatory will be aired on the Science Centre Singapore’s YouTube channel.
For a good view of the comet, Dr Koh recommends locations near bodies of water, such as reservoirs, where trees and buildings will not obstruct one’s line of sight.
“Persistence is key – if you can’t see it one night, try again the next. Keep looking and don’t give up,” he added.
Comets are icy objects made of frozen gases, rocks and dust left over from when the solar system formed about 4.6 billion years ago. Their orbits around the Sun can take hundreds of thousands of years to complete.
They are known for their tails, which are produced by the release of gas and dust when the comet’s ice turns into gas and dust.
According to the NUS Astronomical Society, it is possible that Comet C/2023 A3 has been orbiting the Sun, taking millions of years to come this close to Earth. If it is not orbiting the Sun and just passing through our solar system, it will never return.
This image was taken on Oct 1 between 5 to 5:30am, during a flight from Singapore to China over the South China Sea. - PHOTO: COURTESY OF MR SUCHANG LIU, NTU ASTRONOMICAL SOCIETY
The comet is particularly exciting to stargazers and astronomers around the world because its peak brightness is rivalled only by a few previous comets, said Ms Mirabelle Pei, a mentor with NTU Astronomical Society.
Astrophotographer and Tasos member Akash Anandh, 43, said a comet that is visible to the naked eye is extremely rare. “There is no fixed frequency (of when one can be seen) as comets appear randomly. There can be decades without such a comet and there can be decades with more than one such bright comet,” he added.
As they are made of dust and ice, many tend to disintegrate and disappear from view as they move closer to the Sun, added Mr Anandh.
Comets are traditionally named by or after the person or observatory that discovered them.
In this case, Tsuchinshan-Atlas refers to the two observatories that discovered the comet, namely Purple Mountain Observatory – or Tsuchinshan – in China on Jan 9, 2023, and Asteroid Terrestrial-impact Last Alert System (Atlas) in Africa on Feb 22, 2023.
The letter C in C/2023 A3 refers to comets that take more than 200 years to finish an orbit around the Sun, or those that have passed through our solar system once. 2023 represents the year the comet was discovered.
The comet was found on Jan 9, hence the A in the name, which refers to the first half of the month (B is for the second half), while the number 3 means the comet was the third object discovered in the first half of January 2023.
