| Correspondent
Comet NEOWISE was discovered on March 27 by NASA’s Near-Earth Object Wide-field Infrared Survey Explorer.
That’s where its name comes from.
Shortly after discovery, astronomers had no idea that NEOWISE would become anything special.
Like all comets, NEOWISE is a chunk of ice and dust left over from the formation of the solar system billions of years ago. When comets like NEOWISE near the sun, energy from the sun acts on its ices and creates a fuzzy coma of gas and dust around the core, or nucleus. That gas and dust is pushed away from the sun to form the comet’s signature tail.
During July, I chased this comet — or, more specifically, I chased locations where there was a clear sky where I could photograph it. A clear evening is a tall order on summer nights here in the Southeast where late day thunderstorms are the rule.
The chase took me to some familiar places — locations where I’ve been before where past comets have hung in the sky.
A large field between Stedman and Wade provided a dark sky with unobstructed horizons while Grandfather Mountain in western North Carolina allowed me to get above some of the summer haze we have in the southeastern part of the state.
I had photographed other bright comets previously from both locations, including Halley’s Comet in 1986 and Comet Hale-Bopp in 1997. In fact, most of the time I’ve been on Grandfather Mountain at night for the past 35 years has been to photograph a bright comet.
A “bright comet” generally means one visible to the naked eye, not one necessarily bright enough to be an obvious object. We’re lucky if we see a dozen of them in a typical lifetime. The last bright comet that was as visible as well as NEOWISE for us in the northern Hemisphere was Hale-Bopp in 1997, so decades can pass between bright comet appearances.
The draw of photographing bright comets, besides the rarity of them, is driven by the fact that long exposure photographs lasting several seconds or minutes reveal details that are not readily seen visually, even if we observe the comet with a telescope. Also, comets are dynamic, changing celestial objects. They can change dramatically in brightness and appearance from one night to the next.
Modern digital cameras can accumulate the faint wispy light from comets during long exposures and record colorful and detail-filled images of these special visitors. Since the exposures can be minutes long, my cameras were attached to tracking mounts that followed Comet NEOWISE as the earth rotated during the exposure. Otherwise my pictures would be trailed and blurry. Setting up such tracking mounts and cameras can take a half hour or more.
The best views and photographs of comets come from locations that have the clearest, darkest skies far from city lights. There’s also optimum latitude for observing each comet so it’s positioned as high as possible in the sky.
Fading now as it moves away from both the sun and Earth, NEOWISE won’t return to our vicinity for almost 7,000 years.
I figure that shooting pictures of this rare visitor makes driving a few miles and losing some sleep worth the chase.
If you have a question about astronomy, send it to Backyard Universe P.O. Box 297, Stedman, NC 28391 or email [email protected].
