A rare and newly discovered green comet named Nishimura is set to make a remarkable appearance in the sky before disappearing for the next four centuries. The half-mile-sized comet will be visible to the naked eye in the Northern Hemisphere for five mornings after entering our solar system on Tuesday. EarthSky has reported that Nishimura will be closest to Earth on September 12, passing from a safe distance of 78 million miles away as it travels towards the sun. If it survives its encounter with the sun, the comet may be visible again at the end of the month, but this time only from the Southern Hemisphere.

While visible to the naked eye, observers are warned that Nishimura's trail will be faint. Those hoping to catch a glimpse of the comet should look towards the northeastern horizon about 90 minutes before dawn. Nishimura will pass about 10 degrees above the horizon near the constellation Leo. However, as the comet makes its way closer to the sun, it will become brighter but also drop lower in the sky, making it trickier to spot. Paul Chodas, the manager of NASA's Center for Near-Earth Object Studies, advises that a good pair of binoculars will be needed to locate the comet.

Nishimura was discovered just a month before it is expected to pass through our solar system. Amateur Japanese astronomer Hideo Nishimura captured the comet while photographing the night sky on August 11 and 12. The comet had been hidden in the sun's glare until Nishimura spotted it in his images. This marks the third comet discovered by the amateur astronomer.

Experts have limited knowledge about the comet, but they theorize that it may be the source of an annual Sigma-Hydrid meteor shower that occurs between December 9 and 12 each year. The comet itself is believed to have last visited 430 years ago, a decade or two before Galileo invented the telescope.

The comet's close proximity to Earth has generated significant interest among astronomers and stargazers. Italian astronomer Gianluca Masi, founder of the Virtual Telescope Project, describes the comet as “amazing” with a "long, highly structured tail." He believes that next week will be the last feasible opportunity to observe the comet, considering its rarity.

The discovery of comets by amateur astronomers is a rare occurrence due to the extensive use of powerful ground telescopes by professionals. Paul Chodas acknowledges this and commends Hideo Nishimura for his remarkable find, stating, "This is his third find, so good for him." The comet's appearance has sparked excitement and curiosity among space enthusiasts and the public alike.