If the weather is clear this evening, we invite you to step outside and look up at any time one to two hours after sunset.
If you’re lucky enough to be far enough away from bright lights, step out of a long lounge or lounge chair and relax. Once your eyes have fully adjusted to the darkness, you can count several hundred stars of varying degrees of brightness.
But you can also see other interesting sights, including the International Space Station, the largest and brightest object currently orbiting the Earth.
Relating to: Track the ISS: How and where to see it?
Maybe you catch a glimpse of an extraterrestrial intruder; A sudden streak of light that lasts no more than a second or two at most and probably leaves a brief incandescent trail behind.
Ancient stargazers believed that such an image was a star falling from its fixed position in the sky. Although the terms “shooting star” and “shooting star” are commonly used today, we call these meteors today. Such objects are particles usually no larger than a pebble or grain of sand that hit our upper atmosphere at speeds as high as 45 miles (72 km) per second; Their kinetic energy is converted into light almost instantly, creating a shooting star effect. Most meteors first appear at an altitude of 80 miles (130 km) and disappear about a second later at an altitude of perhaps 40 miles (65 km).
There’s also another group of intruders that have been with us since the dawn of the space age, some 67 years ago: artificial satellites.
Unlike meteors, they are much larger: They are actually human-made structures orbiting our Earth and traveling in orbits around our home planet at average speeds of “only” 8 km per second.
Perhaps the best visual description for a satellite was by the late British satellite observer Desmond King-Hele (1927-2019). In your excellent book, “Observing Earth Satellites” (Van Nostrand Reinhold Company, 1983) wrote: “A satellite is like a star that has decided to abandon its senses and move to another part of the sky.”
Moons are visible at night because their metallic surfaces are illuminated by the sun. A satellite entering the Earth’s shadow instantly disappears and follows an unseen path until it emerges into full sunlight again.
How many?
Right now, if you go out and examine the sky carefully between 30 minutes and two hours after sunset or two hours and 30 minutes before sunrise, there’s a good chance you’ll see about 15 to 30 satellites varying in brightness. From as bright as the brightest stars (zero or first magnitude) to moderately dim objects around fourth magnitude. This shouldn’t be too surprising when you consider how many objects are currently orbiting the Earth.
The first satellite was Sputnik 1, launched in October 1957. Since then, there are now approximately 9,500 satellites in orbit around Earth. Most of these are active payloads, but there are also 100 million pieces of “space junk” ranging in size from 30 feet to the size of a softball, and literally millions of smaller pieces; these can still result in disaster. They hit another object in orbit. U.S. Space Command in Colorado Springs, Colorado, constantly monitors any debris in orbit.
Most satellites are too faint to be seen with the naked eye. But a few hundred or more can be seen with the naked eye, depending on who’s counting. These are satellites that are large enough (more than 20 feet or 6 meters in length) and low enough (100 to 400 miles, or 160 to 640 km above Earth) to be most easily seen.
The biggest!
TOP TELESCOPE SELECTION:
Looking for a telescope to see the ISS in the night sky? We recommend the Celestron Astro Fi 102 as our top pick in our guide to the best telescopes for beginners.
By far the largest and brightest of the man-made objects orbiting the Earth is the International Space Station (ISS), assembled and currently maintained by the United States, Russia, the European Space Agency, Japan, and Canada. The station’s solar panels are 240 feet (73 meters) wide, rivaling the wingspan of a Boeing 777. The station itself is 357.5 feet (108 meters) long, or just one yard shy of the full length of a football field. end regions. It weighs 925,335 pounds (462.7 tons).
Circling the Earth at an average altitude of 260 miles (420 km) and a speed of 17,500 miles (28,200 km) per hour, it may appear to be moving as fast as a high-flying jet plane; sometimes it takes six or more. Seven minutes to cross the sky. It can easily be confused with airplane lights.
Nominally, it appears white with a slight yellow tint and can reach a nominal visual magnitude of bright -1.8 (rivalling Sirius as the brightest star in the night sky), although at its brightest it can sometimes appear as bright as magnitude -5.6. , Which one Twice brighter than the planet Venus!
Although the ISS appears to the naked eye as a very bright, moving star, those who were able to operate a telescope on it were able to detect a T-shape moving rapidly across their field of view. Some were actually able to follow the ISS with their scope, moving it along the projected path. Those with a good view describe the space station’s body as bright white, while its solar panels appear coppery red.
Simply put: if the ISS is moving across your sky, it is almost impossible to miss!
Many windows of opportunity are displayed
From now until the end of May, North Americans will have plenty of opportunities to see the ISS fly over their homes, especially due to seasonal conditions. As we approach the summer solstice on June 20, night hours become shorter and the time a satellite in low Earth orbit (such as the ISS) is illuminated by the sun may extend into the later hours of the night. it is never reachable at other times of the year.
Since the ISS orbits the Earth on average every 90 minutes, this means that it is possible to see it not just in a single pass, but in several consecutive passes.
There are two types of transitions visible for most locations. In one case, the ISS initially appears in the southwestern part of the sky and then moves towards the northeast. But in other cases, it becomes possible to see a second type of transit, where the ISS initially appears towards the northwestern part of the sky and moves towards the southeast.
In the most extreme cases, you may be able to catch the ISS four or more times in a single day!
Case in point: From New York City on Friday, May 10, it will take about 3.5 minutes for the ISS to glide low over the north-northwest to northeast horizon. At 03:44, a slightly higher passage will begin, moving from northwest to east-southeast and lasting about 5 minutes. At 22:01 the same evening, a noticeably higher, brighter and longer passage will begin in the west. It will move towards the southwest and end in the northeast after about 7 minutes. Along the way, the ISS will climb two-thirds of the way from the north-northwest horizon to the point directly overhead.
Later that evening, the ISS will make a much lower pass from west-northwest to north-northwest, lasting 2 minutes, starting at 11:39 p.m. The ISS will then quickly disappear as it enters the Earth’s shadow.
Where and when exactly should you look?
So, what is your hometown’s monitoring program? You can easily find out by visiting one of three popular websites:
-
Find the Station – This site will tell you when and where to see the ISS. All you have to do is type in your city or town, then locate on the map to get all the details. You can even sign up to receive email or text alerts as the space station flies.
-
The Skies Above by Chris Peat – This site will not only provide you with the visibility information of the ISS, but also provide information for Tianhe-1. You must register first, then you can enter your location to create an observation schedule.
-
Live Real-Time Satellite Tracking – Like Heavens Above, you can get visibility information of both ISS and Tianhe-1. When you log in to this site you will automatically be provided with details based on your IP address or you can specify a “custom” location.
Predictions calculated several days in advance are usually correct within minutes. But they may change as the space station’s orbit slowly decays and periodically reascents to higher altitudes. Check for updates frequently.
Clear skies and happy hunting!
Joe Rao is an instructor and visiting professor in New York Hayden Planetarium. writes about astronomy Natural History magazine, Farmer’s Almanac and other publications.