New Comet SWAN brightens, while Comet ATLAS continues to fragment and Comet PanSTARRS holds steady.

There's a lot happening in the northern sky these days, namely lots of comets! Comet ATLAS is still worth watching, but look for the new Comet SWAN (C/2020 F8). And you can still catch a glimpse of our old friend, Comet PanSTARRS (C/2017 T2).


Comet ATLAS (C/2019 Y4) continues to shed fragments while slowly fading and becoming more diffuse. But it ain't dead yet!

Comet ATLAS Fragmenting
© Gianluca Masi and Nick Haigh
The evolution of Comet ATLAS's fragmenting pseudo-nucleus is clearly visible in these images taken between April 6th and 14th. The brightest fragment situated off-axis from the other pieces may be the original nucleus. In the final frame note that it has developed a tiny tail of its own.
Observers are still spotting the crumbling object in 100-mm binoculars and (dimly) in 6-inch telescopes under dark skies. On April 14th at 3h UT the comet's overall magnitude had faded to 9.4, but striking changes have occurred within the inner coma. The nuclear region is now clearly elongated east-to-west with hints of fuzzy condensations visible along its length, using magnifications upward of 300× and averted vision.

On two recent evenings I was able to momentarily catch sight of the brightest fragment (pictured above) along with one or two additional fuzzy stellarings, faint starlike objects that appear on a nebulous object, in my 15-inch Dob at 400×. I encourage observers with larger telescopes to seek these amazing nuggets out. How often do we get the opportunity to see a comet come apart?

The coma measured 4′ across on April 14 at 3h UT, but when I added a Swan filter, which enhances emissions from gassy comets, Comet ATLAS brightened relative to the background sky and the coma expanded to 5′. Although I spotted the comet faintly in 10×50 binoculars on April 1oth, it was invisible on April 13th. This chart (black-and-white PDF here) is still good for locating ATLAS through late April. Assuming the comet soldiers on I'll update the chart next week.

New Comet C/2020 F8 Path
© SkyMap software
New Comet C/2020 F8 is expected to brighten from 6th to 4th magnitude during May as it slingshots from Pisces into Perseus. Positions are plotted daily starting at 0h UT May 5 with stars to magnitude 6.5.

Meanwhile, Michael Mattiazzo of Australia has found a new comet named Comet SWAN (C/2020 F8) in imagery taken by the Solar Wind ANisotropies (SWAN) camera on the Solar and Heliospheric Observatory (SOHO) and publicly available here.

Comet SWAN is presently 8th magnitude, compact, and brightening steadily as it plows across Piscis Austrinus at dawn for Southern Hemisphere observers. Soon it will swing northward, making its first appearance in Aquarius at 7th magnitude for southern U.S. observers by month's end.
Comet SWAN (C/2020 F8)
© Rolando Ligustri
Comet SWAN (C/2020 F8) is expected to reach naked-eye visibility by mid-May low in the east at dawn. On April 13th it presents a bright, dense coma and a spike of a tail.
Comet SWAN (C/2020 F8) will continue to brighten and move rapidly northward in the May dawn sky reaching a peak magnitude of 3.5 between May 15-23 while racing from Triangulum across Perseus. Though bright, the comet remains low in the northeastern sky at the start of dawn throughout the best part of its apparition. Amazingly, Comet SWAN arrived just in time to pinch-hit for ATLAS in the event that comet disintegrates completely. It even reaches peak brightness in the same area of the sky. Perihelion occurs on May 27th at a distance of 64.3 million kilometers.

© Skymap
Comet PanSTARRS should hold steady at 8th magnitude as it arcs toward the Bowl of the Big Dipper this spring. Positions are marked every five days with stars to magnitude 8.
Our final comet, a steady and reliable performer thus far, has taken a back seat in light of all the excitement about naked-eye and disintegrating comets — Comet PanSTARRS (C/2017 T2). It's doing just fine, thank you, as it plies a path across Camelopardalis toward the Big Dipper. From dark skies it's relatively easy to see in 10×50 binoculars at magnitude 8.5. Through my 15-inch on April 11th at 2h UT at 64× I saw a strongly condensed 3.5′ coma with a broad 9′ tail pointing southeast.

With so much happening in the sky right now, don't miss the next clear night.