Check my feed every day this week and next for a daily “comet tracker” with sky-charts and tips for viewing Comet A3.
What time will comet A3 be visible today and tomorrow? Comet A3, also known as Comet Tsuchinshan-ATLAS (C/2023 A3), is on the verge of putting on a show to those in the northern hemisphere.
It’s expected to brighten dramatically, first in the east before sunrise, then in the west after sunset.
Whether it becomes truly an easy-to-see naked eye target from across the world remains to be seen, but the early indications are very good. With some good planning, clear weather and well-timed observing, comet A3 and its bright tail should make an eye-catching sight this late-Sept. and mid-Oct.
Check my feed every day this week and next for a daily “comet tracker” with sky-charts and tips for viewing Comet A3.
Where To See Comet A3: Friday, Sept. 27
Position: east-southeast, 22.6 degrees from the sun in Sextans
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: 58.6 million km
Comet’s distance from Earth: 138 million km
This morning, comet A3 will reach its perihelion and should reach its brightest just as it becomes visible to those in the northern hemisphere. It should be visible just above east-southeast about 75 minutes before sunrise and will be best seen in astronomical darkness, which will last until about 60 minutes before sunrise.
Where To Livestream Comet A3: Friday, Sept. 27
Watch a livestream of Comet A3’s perihelion at 11:00 p.m. EDT on Sept. 27 from the Virtual Telescope Project, which is based in Italy, so will be viewing the comet before just sunrise. It will be broadcast on YouTube.
The Virtual Telescope project also intends to livestream comet A3 after sunset on Oct. 9.
Why Comet A3 Is Getting Brighter — And When To See It
Comet A3 is moving to a position in between the Earth and the sun. On Sept. 27, comet A3 will reach its perihelion — the closest it gets to the sun — at about 36 million miles (59 million km). Comet A3 will get closest to Earth on Oct. 12, when it will pass about 44 million miles (71 million km) from Earth.
Those two dates are key times to view the comet, which will have two distinct observing periods for those in the northern hemisphere.
Exactly When To See The Comet
- Sept. 27: comet A3 will reach its perihelion — the closest it gets to the sun — at about 36 million miles (58 million km). It will be visible in the east an hour before sunrise from Sept.27 through Oct. 3.
- Oct. 12: comet A3 will reach its closest to Earth at about 44 million miles (71 million km) from Earth. It will be visible in the west an hour after sunset from Oct. 12 onwards, but fading each night.
During both of these periods, its dusty tail will reflect sunlight precisely because of its favorable position between the sun and Earth. It’s known as “forward scattering” to astronomers because it scatters sunlight in the direction of Earth — and into the eyes of observers.
Wishing you clear skies and wide eyes.
