In October, you can see two rare comets in the sky at once – C/2025 (Lemmon) and C/2025 (SWAN). They already have distinctive green tails, visible through telescopes and cameras, and the best conditions for observing with the naked eye are expected in the second half of the month. About this notifies The Washington Post.
Comet Lemmon will be best visible from October 12th to November 2nd, and its maximum brightness will occur on the night of November 1st. First, it will appear in the constellation Volopas, and later it will move to Ophiuchus. Comet SWAN is recommended to be observed from October 18 to 21 on the southwestern horizon – it will pass through the constellations Ophiuchus, Sagittarius and Capricornus.
These phenomena coincide with the Orionid meteor shower, the maximum of which is expected on October 20-21. This will create a unique opportunity to simultaneously observe several celestial events.
Comets are composed of ice, dust and rocky particles. As they approach the Sun, their ice evaporates, forming a cloud of gas and a tail. Two tails can be seen in the telescope: a wide white dust tail and a narrow colored tail, the glow of which is caused by ionization of particles. The green glow is usually caused by carbon fumes.
Both comets originate in the distant Oort Cloud. Lemmon will become visible from Earth again in about 1,300 years, and SWAN in about 700 years. In addition, another comet, C/2025 Atlas, is passing nearby this month, but it is too faint to observe without special equipment. Comet viewing requires dusk and a location with an open view of the southwestern horizon.
