NEOWISE
© Michael Mattiazzo on June 10, 2020 @ Swan Hill, Australia
This image of comet C/2020 F3 (NEOWISE) was taken on 2020 June 10 at 08:30UT Using a Celestron C11 RASA f/2.2 on a Skywatcher AZEQ6 mount and Canon 6D camera, 4x30sec combined exposure. The comets solar elongation was a mere 21 degrees! The comets altitude above local horizon was 5 degrees. My approximate visual estimate was 6.8 using 15x70mm binoculars. The well condensed coma was 4' wide. Tail length on image = >40' in PA 149. Heliocentric distance = 0.72AU Earth distance = 1.56AU Hopefully the comet will survive perihelion and be a case of third time lucky for northern hemisphere observers.
NAKED-EYE COMET NEOWISE?

Here we go again. A comet is falling toward the sun, and it could become a naked-eye object after it skims past the orbit of Mercury on July 3rd. Michael Mattiazzo photographed Comet NEOWISE (C/2020 F3) on June 10th from Swan Hill, Australia.

"Pushing the limits of comet observing, I had to leave home to find a clear horizon," says Mattiazzo. "When I took the picture, Comet NEOWISE was very close to the sun and only 5 degrees above the local horizon. Its visual magnitude was near +7.0, below the threshold for naked-eye visibility."

It might not look like much now, but this comet could blossom in the weeks after perihelion (closest approach to the sun). Forecasters say Comet NEOWISE might become as bright as a 2nd or 3rd magnitude star. Northern hemisphere observers would be able to easily see it in the evening sky in mid-July.

comets map 2020
At this point, readers may be experiencing a feeling of déjà vu. Almost the exact same forecast was issued for Comet ATLAS (C/2019 Y4) in March and Comet SWAN (C/2020 F8) in May. Both comets dived toward the sun and ... instead of blossoming, died. Intense solar heat can do that to a fragile ball of ice.

Mattiazzo, who is one of the world's most experienced amateur comet observers, thinks Comet NEOWISE could turn out better. "I'd say there's a 70% chance this comet will survive perihelion," he says, basing his guess on the stability of the comet's light curve, which sets it apart from Comets ATLAS and SWAN. "Hopefully, Comet NEOWISE could be a case of 'third time lucky' for northern hemisphere observers."

We'll know soon enough. On June 22nd, the comet will enter the field of view of SOHO's C3 coronagraph-a space-based instrument that blocks the glare of the sun to reveal nearby stars, planets and comets. For a whole week, astronomers will be able to monitor Comet NEOWISE as it approaches the orbit of Mercury. If it falls apart, the event may be visible in the images. Ditto if it survives.

SOLAR SECTOR BOUNDARY CROSSING

Earth is about to cross a fold in the heliospheric current sheet--a vast wavy structure in interplanetary space separating regions of opposite magnetic polarity. The crossing, called a "solar sector boundary crossing," is expected on June 16th and could trigger minor geomagnetic activity around Earth's poles.