Comets in history
Comets have fascinated mankind for thousands of years. These icy visitors from the outer reaches of the solar system caused terror, reverence and even joy, depending on when and where you lived. The heavens were something that everyone paid attention to in the age before artificial lighting made the sky a bland picture for modern man. Shamans and priests predicted celestial events like eclipses, however the appearance of a comet sent everyone into a tailspin. A new light in the sky was often seen as the beginning of the end and most early peoples were afraid when one arrived unannounced. The Bayeux Tapestry (seen below) has a panel depicting a star with a streaming tail, which was probably Halley's Comet that arrived right on schedule in 1066. However, the people didn't know this, since it was only in 1758 when Edmond Halley used reports of a comet that returned every 75 years to predict its appearance. Today, we have the benefit of science and can predict when most of these celestial wanderers will return.
Comet NEOWISE is a recent discovery
Comet NEOWISE is a previously unknown and unexpected visitor and the whole world is anxious for a glimpse. It was discovered in late March by the orbiting Wide Field Infrared Survey Explorer Telescope. It studies near Earth objects like asteroids (small space rocks that aren't moons) and the compositions of many stars. NEOWISE is an acronym for its mission to study Near Earth Objects. The comet was unexpected and surprised scientists on how fast it brightened. Comets do not shine with their own light, like a star or a meteor burning up in the atmosphere. Comets are balls of ice, rock and dust that shine with the reflected light of the Sun, just like our moon, or any of the planets we can see. So it isn't burning and is brightest when it is close to the Sun. The problem with this is, that the Sun can destroy a comet and blast it to pieces just by gravitational pull and heat, so many do not make it after that encounter. NEOWISE did and brightened enough for it to be visible to the naked eye, which is rare for a comet. We have several comets that return on a regular basis, however they are at best binocular objects or even telescopic. NEOWISE will return as well, however it will be almost 6,800 years before anyone on Earth will see it again. It could be that the druids that built Stonehenge saw it, however since that was before writing was invented, we'll never know if they did, or what they thought about it.
Basic astronomy helps locate NEOWISE
There are some lovely images on the Internet of NEOWISE and I even shot some myself, however it takes a bit of preparation and planning to capture it. I've had friends say they can't find it and that is because spotting this comet with the naked eye is hard to do. The comet is just a small, faint, fuzzy streak to the human eye. You'll need an accurate star map with the location highlighted and know how to use one. A basic knowledge of the stars is also helpful, as in the names of surrounding bright stars and constellations. If a planet is wandering nearby, it's good to know which one. Venus was spectacular the other morning when I was out and it was a treat even if there wasn't a comet. Be sure to take in the whole sky, it is wonderful.
Spotting a comet
I also had my binoculars handy to verify the comet was what I was seeing. Get your bearings with a bright star on the map and find that in the sky. Take the binoculars and slowly search the area where the comet is supposed to be. It should show up easily in the field of vision and look bright. When you find it, you can then see what it looks like without artificial assistance. Don't worry, it isn't going anywhere. That's another misconception that people have. I've had dozens of people say, they've seen it as it zipped right by. That isn't the comet. Comets don't zip or move quickly. They slowly rise or set just like the moon does. The morning I shot my image, NEOWISE rose just before the sun. It was just above the treeline as the sky was turning light. With the sun up, the comet would still be there, however since it was light, no one could see it. Now, the comet has moved to a point where it is visible at sunset as opposed to sunrise. This is because as the Earth travels around the Sun, the comet appears to have shifted its position. Actually, both the Earth and the comet have moved. The Earth in its orbit around the Sun and the comet heading back out into the outer limits of the solar system.
Spotting NEOWISE in the evening
To see NEOWISE in the evening, first locate the Big Dipper about an hour after sunset if you can. The sky may still have a bit of light in it, depending on your latitude. Most people already know how to find that asterisim in our northern skies. Where the Big Dipper is tilted, as if it were pouring something from its bowl, follow that imaginary path of liquid down to the horizon. NEOWISE should be somewhere in the imaginary pouring area, near the horizon. On the 14th, it was right on the horizon and each evening afterward, a bit higher and back toward the handle in the sky. The tail of the comet will be pointed upward. It will decline in brightness as it gains altitude each evening. You will probably need binoculars, especially if you've never seen a comet before. By July 23rd, it will be almost as high as the Big Dipper and a bit behind the bowl, under the handle. The drawing below shows where you should look for it each night. The little dots below the Big Dipper show where it will be from the 18th through the 23rd. If you want to photograph it, use a tripod and an ISO of at least 800. I used a one second shutter speed an aperture of 5.6 on a 105 mm lens for this image. Anything longer than one second caused the image to blur because of the comet creeping up in the sky.
There's much to learn about the night sky
Naked-eye comets are a rare gift and everyone who has access to dark night skies should at least try to catch a glimpse of this one. We have a number of binocular and telescopic comets that we know their return times, however none are destined to be of much note unless they brighten unexpectedly. I've seen three or four naked-eye comets in my lifetime, so they aren't commonplace. Use this as a learning experience. Take your kids out at night and learn about the sky. Even after the comet is gone, there are many things that they will find interesting. Let them learn to recognize the visible planets. Watch the International Space Station make a loop across the sky. Learn the constellations and sit out during meteor showers. There's so much to see and so much to learn, we should all stop and look up at night.