Astro Bob: How to see comet Tsuchinshan-ATLAS at dusk – Duluth News Tribune

The comet is back! Many of you had difficulty finding it in the morning sky last month because it was so close to the horizon. Thick air and haze absorbed much of the comet's light, making it nearly impossible to locate. Observers much further south had an easier time because it was higher in the sky.

I tracked the fuzzball over six mornings and never saw it with the naked eye, only through the camera's viewfinder and once with binoculars. Fortunately, the evening appearance of Tsuchinshan-ATLAS will be more accessible, although perhaps not as bright as expected, partly due to interference from moonlight.

I was ready on October 11th when the comet first appeared in the evening sky. Conditions were very good with clear air and only a few distant cirrus clouds. I located Venus in the southwestern sky and measured 2 1/2 fists to the right of it. After several attempts, I was able to spot the comet at 7:10 p.m., 40 minutes after sunset, using my camera and then 10×50 binoculars. It was weak! But as dusk grew, it became easier to see – my binoculars even showed a short tail. I tried hard to see the comet with my naked eye, but I couldn't convince myself that I had seen it.

Although Tsuchinshan-ATLAS is much fainter than Venus, the luminous planet will help you get there. Until about October 19, the comet will remain about 2 1/2 fists from Venus, although the angle it forms with the planet will gradually increase.

Don't worry too much if the comet looks faint visually and in photos right now. It is still low and is heavily affected by twilight and haze. Things will improve soon.

Contributed / Stellarium with additions from Bob King

The map shows that the comet will rise quickly in the western sky in the coming nights. If you look at the same time every night, you will notice that the altitude is steadily increasing. That's a good thing! This means less air and dust has to filter out the long, sensitive tail. The comet will set for about 40 minutes by October 14th after the end of dusk in a dark sky. In the following nights the “window” of darkness becomes longer and longer.

For this reason, visibility of the comet is expected to improve over time. And they will. However, as altitude increases, Tsuchinshan ATLAS also slowly fades as its distance from Earth increases. It goes back into the “wilds” of the solar system far beyond the orbit of Pluto. There's even a chance it could escape the sun entirely and find its way into interstellar space.

We also have another problem – the moon. At the moment it is in the increasing gibbous phase and will be full on October 17th. Its light will dull the comet's brilliance and “shorten” the apparent tail length from about October 15 to 20. After that we are in the clear!

On the 20th, Tsuchinshan-ATLAS should reach about 3rd magnitude and have a nice, long tail that is easily visible to the naked eye in a dark, rural sky. If you live in the suburbs, you'll need binoculars to see it well. But no matter where you observe from, binoculars will help see the full extent of the comet's tail, as well as all of its textures and colors. If you have a scope, bring it with you to get a close look at the glowing core region in the comet's head.

Contributed / Stellarium with additions from Bob King

Pay particular attention to the comet on the evenings of October 14th and 15th. Then we should see a prominent countertail protruding from just below its head. This delicate peak of light occurs when we view the comet's orbit from the edge. Dust that has been deposited along its orbit over the past few months is piling up and briefly shining as a secondary tail from our perspective.

Contributed / Ben Schurman

And don't forget your phone. You should have no problem photographing comet Tsuchinshan-ATLAS at dusk with an ordinary smartphone. Just hold it up, tap the comet to focus, then tap again to take a picture. A handheld phone can typically expose between 3 and 10 seconds. However, if you purchase a phone mount and attach it to a tripod, exposure times of up to 30 seconds are possible.

I will continue to post new photos and updates about the comet on my Facebook page at facebook.com/astrobobking. Clear skies and happy hunting!

“Astro” Bob King is a freelance writer and retired photographer for the Duluth News Tribune. You can reach him at [email protected].