Comet Neowise by Richard Covey, Edmonton Alberta. Used with permission.
FORT MCMURRAY, AB — Stargazers in Fort McMurray are in for a treat this month as Comet Lemmon (C/2025 A6) makes a rare and vivid appearance in Alberta’s northern skies. The comet, easily recognizable by its glowing green tail, will make its closest approach to Earth on Oct. 21 and could be visible to the naked eye under clear, dark conditions.
In Fort McMurray, the best viewing will be in the pre-dawn hours through mid-October, looking toward the northern horizon near the Big Dipper and the constellation Canes Venatici. As the month progresses, the comet will shift into the evening sky, making it easier to spot after sunset. Around Oct. 16, it will pass within a degree of the bright star Cor Caroli, offering a useful reference point.
Astronomers say Lemmon’s green glow comes from diatomic carbon (C₂) — a molecule that fluoresces when sunlight breaks it apart in the near vacuum of space. This reaction produces a striking emerald hue in the comet’s coma and tail, visible through binoculars or a small telescope.
Richard Covey, a member of the Royal Astronomical Society of Canada and a published astrophotographer, said the combination of colour and visibility makes Lemmon worth losing sleep for. “If you can find a dark spot with a clear view north and northeast, and get out before dawn around 4:30 or 5 a.m., you’ll see one of the most beautiful comets in years,” he said. “The green glow is subtle to the eye but spectacular through a camera or telescope.”
Covey added that mid-October offers the best chance for Fort McMurray residents to catch the comet. “By about Oct. 20, Lemmon should be near peak brightness. After that, you can try watching just after sunset, though it’ll be lower on the horizon and trickier to spot in the city’s glow,” he said.
Viewers are encouraged to dress warmly, bring binoculars, and give their eyes time to adjust to the dark. If skies cooperate, Comet Lemmon could reach magnitude +4 by late October, which is bright enough to glimpse unaided from darker areas just outside Fort McMurray.
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