The International Space Station summer visibility season has started in Ukraine. It will be visible in the night sky throughout July.
The ISS is the largest structure ever created by man in space. It is 109 meters long, 73 meters wide, and weighs 440 tons. Due to its impressive size, the ISS is one of the brightest objects in the night sky. Its apparent magnitude can reach -6. This is even greater than the brightness of Venus.
However, we cannot observe the ISS every night and from any location on Earth. First of all, the station is in an orbit with an inclination of 51.6°, which imposes a number of restrictions on its visibility. The ISS, for example, cannot be observed from polar latitudes. Second, the station shines not with its own light but with reflected light. Therefore, it can be seen in the sky only when it flies over an area where it is already dark, but the station itself is still illuminated by the Sun.
This is exactly the scenario that will prevail in Ukraine in the coming weeks. Every night, several passes of the station will be visible when it is illuminated. For a ground-based observer, the station will look like a star (usually the brightest in the night sky) moving across the sky from west to east. On average, the duration of the flyby is about 5 minutes.
A long exposure image of the ISS flyby. Source: David Duarte
In order to find out in advance the time of the ISS flyby, you can use the website heavens-above.com. There, you need to select your location in the panel located in the upper right corner, and then on the main page, click on the “ISS” tab in the section called “Satellites”.
You can also use the Heavens-Above mobile app or some other smartphone program, such as ISS Detector. They show the schedule of the station’s flybys for the coming days and, if you select the appropriate setting, can notify you when it starts.
