Where and when to watch it live and online

Check out my feed every day this week and next for a daily “comet tracker” with sky maps 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 about to put on a show for those in the northern hemisphere.

It is expected to brighten dramatically, first in the east before sunrise, then in the west after sunset.

Whether it will actually become an easy target with the naked eye from around the world remains to be seen, but early indications are very good. With good planning, clear weather and early observation, Comet A3 and its bright tail should make for a spectacular sight this late September. and in Oct.

Check out my feed every day this week and next for a daily “comet tracker” with sky maps and tips for viewing Comet A3.

Where to see Comet A3: Friday, September 27

Position: east-southeast, 22.6 degrees from the Sun in Sextans

Time: one hour before sunrise where you are (around 07:00 in the US)

Expected size: +4.5

The comet’s distance from the sun: 58.6 million km

The comet’s distance from Earth: 138 million km

This morning, comet A3 will reach it perihelion and it should reach its brightest just as it becomes visible to those in the northern hemisphere. It should be visible just above the east-southeast about 75 minutes before sunrise and will be best seen during astronomical darkness, which will last until about 60 minutes before sunrise.

Where to live stream Comet A3: Friday, September 27

Clock a live stream of Comet A3 perihelion at 11:00 p.m. EDT on Sept. 27 by the Virtual Telescope Project, which is based in Italy, so we’ll see the comet before sunrise. it will be broadcast on YouTube.

The virtual telescope project also intends to Live stream of Comet A3 after sunset on October 9.

Why Comet A3 is getting brighter — And when to see it

Comet A3 moves to a position between the Earth and the Sun. On September 27, Comet A3 will arrive perihelion — the closest it is to the sun — at about 36 million miles (59 million km). Comet A3 will make its closest approach to Earth on October 12, when it will pass about 44 million miles (71 million kilometers) from Earth.

These two dates are key times to see the comet, which will have two separate viewing periods for those in the northern hemisphere.

When exactly to see the comet

• September 27: Comet A3 will reach its own perihelion — the closest it is to the sun — at about 36 million miles (58 million km). It will be visible in the east one hour before sunrise from September 27 to October 3.
• October 12: Comet A3 will make its closest approach to Earth at about 44 million miles (71 million kilometers) from Earth. It will be visible in the west one hour after sunset from October 12 onwards, but will fade each evening.

In 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.

I wish you clear skies and open eyes.