When can I see the comet Tsuchinshan-ATLAS? In scenes not witnessed since the "Covid comet" -- comet NEOWISE in July 2020 -- an icy space rock is visible to the naked eye in Earth's sky.
It's also rather convenient. Having exited the sun's glare at the weekend, comet Tsuchinshan-ATLAS (also called C/2023 A3 and Comet A3) is currently rising into the night sky immediately after sunset.
Tonight, Monday, Oct. 14, is the first of the two best opportunities to see the comet at its brightest and best from the northern hemisphere.
Having reached its closest to Earth on Saturday, Oct. 12 -- getting to within 44 million miles (71 million kilometers) -- it will be a healthy 25 degrees from the sun tonight. That's about twice as far as it was on Friday, when keen comet-observers first started searching for it.
The upshot is that it should tonight be visible in a reasonably dark sky. You'll need a good view of the western horizon to see it after sunset. Tonight sees its apparent distance from the sun reach the point where it will be relatively brightest but also set against a darker sky. It will also remain in the sky for longer.
Here's exactly when and where you need to look to see the comet with your naked eyes on Monday, Oct. 14.
Comet's distance from the sun: 55.6 million miles (89.5 million kilometers)
Comet's distance from Earth: 45.1 million miles (72.6 million kilometers)
This evening, the comet will be visible close to the western horizon about 45 minutes after sunset. The waxing gibbous moon will be bright, 91%-lit, which will make the night sky less than dark. However, that shouldn't interfere with comet-spotting too much since the moon will be positioned in the southeast (the moon will also be very close to Saturn, which is a second good reason to be outside after sunset).
If you have a completely clear horizon, find the bright planet Venus and the bright star Arcturus; the comet will be almost exactly halfway along an imaginary line drawn between them.
Tonight is arguably one of the best times to see it. "As twilight fades on Monday, Oct. 14, it will be two fists to the upper right of Venus (if seen from the northern U.S.) or to the right of Venus (if seen from the southern U.S.)," states Sky& Telescope. "As twilight turns to night, the comet will remain in view, its long, straight tail pointing up from the horizon."
All you need to see the comet is your naked eyes, but any pair of binoculars will give you an incredible view.
The viewing period for comet Tsuchinshan-ATLAS began on Friday, Oct. 11 and is set to continue through Monday, Oct. 21, before it fades from naked eye visibility.
Early this week the comet "will be at its best for viewing," states Sky & Telescope. Monday, Oct. 14, and Tuesday, Oct. 15, are likely the technical best evenings to see the comet, but since comet-watching is entirely weather-dependent, it's wise to leave your evenings free for the rest of this week.
Although this comet is visible to the naked eye -- for the first time in 80,000 years -- it's wise to use binoculars to scan the sky for its presence in the fading twilight and to get a good close-up view. But do you need binoculars? "They might if viewing at/before the beginning of the optimal window, or from a very light polluted city where the sky never gets much darker than bright twilight," said astronomer Dr. Qicheng Zhang of Lowell Observatory in Flagstaff, Arizona, who has been monitoring the comet, in an email last week. "From a darker location, especially from the 13th or maybe 14th onward (until at least the 20th, and perhaps up to another week or so after that), no binoculars should be needed to see the comet." However, binoculars will enhance the view, he added.