UPDATE: Early eye-witness reports indicate that comet A3 is not yet a naked-eye object. It’s best seen by taking images, which you can learn more about doing here.
With a new moon, the pre-dawn skies are dark, but seeing comet A3, also known as Comet Tsuchinshan-ATLAS (C/2023 A3), on Thursday, Oct. 3 won’t be easy. Since it’s sinking closer to the sun — it’s now just 18 degrees from our star — it will only be visible for a short window of time an hour before sunrise.
It’s your last chance to see comet A3 until Oct. 12, when it-remerges from the sun’s glare to shine — possibly even brighter — in the western post-sunset sky. (Here’s your ultimate guide to seeing comet A3 in 2024).
It reached its perihelion — the closest it gets to the sun — on Sept. 27 and will get closest to Earth on Oct. 12, when it will pass about 44 million miles (71 million km) from Earth.
Comet A3 is currently visible in in the east before sunrise, its bright tail arching away from the sun, but you do need to be up very early and have a clear view of the eastern horizon.
Here’s how to see it tomorrow, your last chance until Oct. 12:
Where To See Comet A3: Thursday, Oct. 3:
Position: east-southeast, 18.2 degrees from the sun in Leo
Time: an hour before sunrise where you are (around 07:00 in the U.S.)
Expected magnitude: +4.5
Comet’s distance from the sun: 62.9 million km
Comet’s distance from Earth: 100.4 million km
Here’s the last real chance to see comet A3 during this first observing window. It will be visible even closer to the east-southeast and be best seen about 75 minutes before sunrise in astronomical darkness, which will last until about 60 minutes before sunrise.
When To See Comet A3 This Weekend
Comet A3 will now dip into the sun’s glare, and be much harder to see for a few days before being swallowed-up completely by our star’s light. Here are sky-charts for Oct. 4-6, but note that comet A3 will be almost impossible to see in the gathering light of dawn:
When To See Comet A3 In Mid-October
Comet A3 will re-emerge in twilight around Oct. 12 for those in the northern hemisphere. Look to the west immediately after sunset to glimpse it possibly at its brightest and best, though in the evenings after Oct. 12, it will rise higher into the sky but likely dim considerably.
Check my feed every day this week and next for a daily “comet tracker” with sky-charts and tips for viewing Comet A3.
Wishing you clear skies and wide eyes.
