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Predawn hours this week provide best chance to see passing comet

The best time to look in central North Carolina is between 4:30 and 5 a.m., when the comet has risen a few degrees above the horizon but before the brightening sky makes it increasingly difficult to see the comet.

Posted Updated
Comet C/2020 F3 (NEOWISE)
By
Tony Rice
, NASA Ambassador

Comet C/2020 F3 (NEOWISE) has brightened to the point it is visible to the naked eye. It's the first comet of 2020 to deliver on its promise after C/2019 Y4 (ATLAS) broke into fragments in April as it approached the Sun.

Comet C/2020 F3 (NEOWISE) made its closest approach to the Sun on July 3, 2020 (JPL Horizons/Rice)

Observers noted a 12-fold increase in brightness between May and June. The comet survived its closest approach to the Sun over the 4th of July weekend, gaining brightness comparable to brighter stars in the big dipper (first magnitude).

When and where to look

Comet C/2020 F3 (NEOWISE) from Falls Lake on 7/10/20 around 4:45 am, four-second exposure (Image: Tony Rice)

The comet rises in the northeast two hours before the Sun and sets with the Sun around 8:30 p.m.  Look for a  point of light with fuzzy tail extending up and slightly to the left.  Comet tails point away from the Sun.

The best time to look in central North Carolina is between 4:00 and 4:45 a.m. The earlier you look, and darker your skies the brighter the comet will be.  The clearer your northeastern horizon, the earlier you can look. Areas north and east of light pollution sources like Raleigh and Durham will have an easier time.  I was able to quickly find the comet from the Falls Lake area on Friday morning.

Comet NEOWISE position the week of July 5 (Stellarium/Rice)

A compass app on your smartphone can also help point you in the right direction. The comet rises at 4 a.m. from 40° azimuth and moves eastward to 50° by sunrise.

The Comet was discovered on March 27, 2020, by NASA's Wide-field Infrared Survey Explorer (WISE) space telescope launched by NASA in 2009 which has been repurposed to find and study Near-Earth Objects (NEO) since 2011.

Why so early?

Comets are most visible when they are closest to the Sun. This heats the surface of these dirty snowballs causing causing them to release gasses, generally water and carbon dioxide. What we see is the coma formed by those gasses and dust ejected by that heating and a trailing tail illuminated by the Sun. 

If early rising just isn't for you, Comet NEOWISE moves to next week's evening north-northwestern sky (around 325° azimuth). But as it continues its upward movement away from the Sun, it is expected to dim, even break apart. Comet expert David Levy put it best :“Comets are like cats: they have tails, and they do precisely what they want.”

This week's predawn hours are expected to provide the best opportunities to see it.

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