The Backyard Astronomer: Spectacular new comet visible to naked eye
Comet NEOWISE won't be back for about 6,800 years, so make sure you see it this time around
A bright comet is now in the evening sky, and you can see it without a telescope.
Comet C/2020 F3 (NEOWISE) has been a fantastic object in the early morning predawn sky, but it will be well placed below the Big Dipper to see and photograph over the next couple of weeks and, hopefully, into August.
I have been following and imaging this comet since the first week of July and could see it even without binoculars (with the naked eye).
The comet was discovered on March 27, 2020, by the Near Earth Object Wide-field Infrared Survey Explorer (thus, NEOWISE) space telescope as it looked for near-Earth objects that could potentially impact our planet. Measuring a little more than half the height of Mount Everest, this object falls into the category of a “once in a decade" comet.
Every year, astronomers both amateur and professional observe five to 10 comets with telescopes. In most cases, they show a green nucleus, which comes from the sublimation of frozen chemicals such as ammonia and others. The extremely faint tail is usually seen when photographed, but all comets are different in composition and appearance (and Neowise does not appear green).
The last bright comet that was visible to the naked eye for the whole world to see was Comet Hale-Bopp in 1997. Like NEOWISE, it had a blue ion, or gas, tail and a fan-shaped dust tail that is created when comets go around the sun, as this one did on July 3 at a "close" distance of 43 million kilometres.
NEOWISE will be closest to Earth on its way out of the solar system, on July 22, at a safe distance of 103 million kilometres. It will be starting to fade, with a shortening tail, as it retreats from the sun's heat and back to the icy depths of space.
Comet NEOWISE originates from the Oort Cloud, where long-period comets reside, and it will return in about 6,800 years. (Halley’s comet, by comparison, is a short-period comet—returning to our solar system approximately every 75 years—originating from the Kuiper Belt.)
Along with the above chart of the comet’s path, many smartphone astronomy apps will also guide you to our celestial visitor. Enjoy this spectacular comet every chance you can, as you never know when the next bright will come to visit.