My Morning With Comet SWAN

Comet SWAN (C/2020 F8) at 3:25 a.m. Wednesday morning, May 19 at the start of dawn from Duluth, Minn. The photo conveys how small the comet appeared in binoculars and also captures its blue-green color apparent in the telescope. The trees are motion-blurred because I used a tracking mount to follow the stars. Details: 200mm telephoto at f/2.8, ISO 400, 50-second exposure. Bob King

At a restaurant we wait patiently for our food to arrive not unlike waiting for Comet SWAN to wend its way up from the Southern Hemisphere sky to the North.  For me that moment arrived at dawn today, May 19th. Weeks ago I expected a visual feast. What I saw this morning more of a tasty morsel. I’ve learned never to complain about comets even when the “underperform,” remembering that they perform for no one.

Use this map to find the comet in the morning sky. It’s drawn for 40° N latitude just as the first hints of dawn appear in the eastern sky. Start by finding the familiar W of Cassiopeia and then drop down to Mirfak and slide further down to within 5-7° above the horizon to spot the comet. Look for a small, blurry blob of light like an unfocused star. The sky doesn’t have to be pitch dark to see the comet. You can observe into early dawn. Stellarium

Still, it would have been nice to see SWAN at its predicted naked eye brightness of magnitude 3. Who knows, it may still get there, but what I saw in 10×50 binoculars was a small, round, fuzzy patch of light about 6-6.5 magnitude. Thanks to the star 16 Persei, located to the comet’s upper left, it was super easy to find. While no tail was visible in my glass it was obvious in short time-exposure photos and through the telescope. I was not able to see the comet with the naked eye.

Through the big gun, a 15-inch (38-cm) reflecting telescope, I immediately noticed the beautiful Mediterranean blue hue of SWAN’s coma, the head of the comet. A tail about half-a-degree long streamed off to the west. The sight made me smile. I increased the magnification to dig deeper inside the coma but atmospheric turbulence at the comet low altitude gave blurry views. I could only see a small, brighter spot at the center called the pseudo nucleus.

This map depicts the comet’s evening apparition from 40°N latitude or across the central U.S. The bright stars Capella and Mirfak will help point the way. Positions are marked every three nights at 10:30 p.m. CDT. Stellarium with additions by the author

I don’t think many people are going to see Comet SWAN after all. Not only is it a few magnitudes fainter than expected but it’s not getting any brighter. For now at least. Of course a big chunk of the comet could cleave at any moment, exposing fresh ice and causing a sudden outburst in brightness. Barring that it will be a challenging object to spot: the comet is low, the viewing interval before twilight short (about 30 minutes) and it’s relatively faint. To guarantee a view it in the coming week when SWAN is brightest and highest you’ll need a pair of 50mm or larger binoculars and a dark, rural sky. You can also use a telescope.

I cropped in on this photo to show the SWAN’s tail better. The overexposed star is 16 Persei in the constellation Perseus the hero. Bob King

For the next three mornings SWAN remains a dawn object visible from 2 hours to 2 hours 15 minutes before sunrise from the northern U.S. and southern Canada. From the central and southern U.S. look for it 90 minutes to 2 hours before sunrise. The comet then transitions to the evening sky around May 23 when becomes visible at the end of dusk. Maps showing the comet’s location at both dawn and dusk are above. Throughout, SWAN will climb to just 5-10° above the northern horizon, so be sure to find a viewing location with a great view in that direction.

Despite SWAN’s humble appearance I hope you go out for a look anyway. It’s currently the brightness comet in the sky by a significant margin and a lovely sight in 8-inch or larger telescopes. Comets, being part of nature, are what they are and that is enough.


3 Responses

  1. Edward M Boll

    It’s been too overcast here. I’ll check the forecast for more clear days. I was going to try for Y1 again, but now it is getting toward 11. I am thinking that Atlas is about 10 now. Exciting to know that Lemmon and Neowise have both been seen now with binoculars of under 10 power. I guess we see both this Summer as they fade out, Lemmon now around 7.

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