How to See Comet Lemmon This October

It was early January 2025 erstwhile a faint ray spot was observed astatine nan Mt. Lemmon Observatory successful Arizona. Follow-up observations revealed that nan entity was a comet visiting from nan outer separator of nan star system, and it was named Comet Lemmon (C/2025 A6). Its “period”—the clip it takes to complete its lengthy orbit of nan sun—is astir 1,350 years.

At first, nan comet was truthful faint that it could only beryllium seen pinch specialized equipment. But it has brightened quickly arsenic nan months person passed, and by nan clip autumn arrived, it was agleam capable to beryllium viewed pinch binoculars. It will now get brighter still, arsenic it gets person to some nan Earth and nan sun, and whitethorn moreover go visible pinch nan naked eye.

According to NASA, Comet Lemmon will beryllium closest to Earth astir October 21, 2025, passing astatine a region of astir 0.60 astronomical units, aliases au (1 au is nan region betwixt Earth and nan sun). The comet is past predicted to scope perihelion—the constituent astatine which it is closest to nan sun—on November 8. Around nan clip nan comet reaches perihelion, it will apt scope its maximum brightness, and whitethorn beryllium visible to nan naked oculus if conditions are favorable successful acheronian skies.

The comet’s tail will besides beryllium astatine its longest hold astir nan constituent of perihelion. Tails shape connected comets erstwhile star radiation heats up stiff crystal and gases contained successful nan comet’s nucleus, causing them to sublimate—transform from coagulated into a gas—with nan radiation past causing immoderate of that worldly to beryllium emitted retired from nan comet successful a telltale streak. The stronger nan radiation, nan greater nan size of this effect, and truthful comets’ tails turn arsenic they get person to stars and shrink again erstwhile they move away.

Comet Lemmon is notable for its greenish tint. This is caused by nan state unreality that surrounds nan comet’s nucleus, known arsenic its “coma,” pinch nan colour being created by diatomic c (molecules of 2 c atoms) interacting pinch sunlight.

How to View nan Comet

As of early October, Comet Lemmon tin beryllium recovered somewhat beneath nan grip successful nan Big Dipper (or nan Plough, arsenic it's known successful nan UK), which forms portion of nan Ursa Major constellation. If you look up astatine nan bluish sky, you will beryllium capable to trace its path. In nan bluish hemisphere, it is predicted to look successful nan northwestern-to-western entity aft sunset from mid-October onward. It will beryllium astatine a debased altitude supra nan sky and is expected to emit a faint glow successful nan twilight conscionable aft nan sun has set.

The champion clip to observe nan comet is astir a week earlier and aft its closest approach. In November, nan comet will transverse nan celestial equator and go visible from nan confederate hemisphere.

Binoculars aliases mini telescopes are champion for watching it, but if you take a location pinch small ray pollution, you whitethorn beryllium capable to drawback it pinch nan naked eye. If you look up astatine nan entity conscionable aft sunset erstwhile it is still a small bright, you whitethorn beryllium capable to spot it. It you are struggling to find nan comet, usage a prima representation exertion connected your smartphone aliases planetarium package to thief you pinpoint its location.