May 14

Observe the ISS across the sky

International Space Station

You probably have seen one day in the night sky a very bright object moving faster than a plane, without blinking, thinking that it was probably a plane. It is more than likely that it was the ISS !

My AllSky station captured the ISS passage last night between 3:04 am and 3:06 am and 4:40 am - 4:43 am, you can see it on the video presented on the right.

See the video in the page of my AllSky

More info

International Space Station
International Space Station

What's ISS ?

The International Space Station, a scientific laboratory in orbit permanently occupied by an international crew is dedicated to scientific space research. This program, launched and piloted by NASA, is developed jointly with the Russian federal space agency Roscosmos, with the participation of European, Japanese and Canadian space agencies.

The station has orbited our planet since 1998 at an average altitude of 400kms, a speed of about 27,500km h and passes over our heads 16 times a day.

It is not visible from all points of the earth at the same time, especially not during the day because it is not directly lit by the sun, but can regularly be visible in the night sky at sunset at sunrise which l 'illuminated.


ISS Observation
ISS Observation

When can I watch ISS ?

About the size of a large house, it circulates in the direction of the rotation of the Earth, from West to East but goes 15.8 times faster than us. The station can be observed twice in a row at 91-minute intervals.

If you see it passes, you cannot miss it: a very bright point (brighter than Venus which remains the champion of the bright stellar objects of the sky), which takes 2 to 6 minutes to cross the sky according to its degrees of elevation , and does not flash. I insist on this, because it gives a rather magical effect to the object, like a UFO which would move in the sky in a straight line without anything seeming to be able to stop.

ISS Moon Transit
ISS Moon Transit

Take a picture of ISS, can we ?

The most experienced astrophotographers love the ISS stereotype race. The goal is to photograph it when it passes in front of the moon or the sun. It is easily possible to identify it on a snapshot, but this exercise remains very very complicated to perform.

See how to take a picture of ISS in opposition.



You can still try to film it: it works very well on a mobile phone or even on a SLR type camera in video mode, at wide angle and in the right direction.


Live Space Station Tracking Map
Live Space Station Tracking Map

What is the current position of ISS ?

To see its race, the ESA website offers us a superb page:

The information shown is its current position, at 1.5 hours and +1.5 hours, its position, speed and altitude. You will notice that these last two figures vary much more than one would imagine. Circulating in orbit is not necessarily a constant path.

It is also possible to see the video it takes in real time on youtube..

So remember to look at the sky this week.


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