The image shows how Comet Atlas will appear when it reaches the point nearest to the sun in late May. (Provided by Shigemi Numazawa)

Stargazers are anxiously waiting to see if Comet Atlas brightens in the night sky to become one of the greatest comets in a century. Or not.

While Comet Atlas is still visible only with a telescope, the celestial object is expected to become increasingly brighter as it makes its closest approach to the sun in late May.

One estimate is that the comet may reach a minus second magnitude around that time, a level brighter than Sirius, the brightest star that can be seen from Earth at night.

Hopes are high that Comet Atlas will show its long, magnificent tail in the night sky to the naked eye.

The comet was first spotted by a telescope of the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Hawaii in December last year.

Although it was initially categorized into a 20th-magnitude one, which is extremely faint, the comet's brightness increased rapidly in March, wowing astronomy fans who anticipate that the comet “may become as bright as the full moon at such a pace.”

The acute rise in brightness lessened later, but Seiichi Yoshida, 45, a famed comet watcher, predicted that Comet Atlas will measure a zero to minus second magnitude toward the end of May.

“The comet is on course to increasingly brighten,” said Yoshida. “It will be bright enough to be visible to the naked eye by the beginning of May, and could reach first magnitude in the middle of the month or later.”

Comet Atlas was comparable to an eighth-magnitude star and could be seen in the area of sky between the Big Dipper and Perseus as of April 1.

It is expected to be visible in the northwestern sky after sunset in April and May. After further nearing the sun, the comet will become difficult to spot from the Northern Hemisphere.

It should be noted, however, that comets, which are often compared to “dirty snowballs” in space based on their constitution, could melt to a greatly differing extent, depending on the strength of sunlight and other elements, which makes it difficult to precisely forecast how bright they will become.

On top of that, the National Astronomical Observatory of Japan pointed out that the comet’s brightness level did not increase significantly in the last week in March.

“The comet may not be so bright,” said astronomy professor Junichi Watanabe, a vice director-general of the observatory, expressing caution. “We should not have so high expectations but I am looking forward to seeing how things will turn out.”