ISS and Satellites

Many artificial satellites can be seen moving across the sky as white dots. They differ from aircraft in that there are no flashing lights. However, satellites can vary in brightness; they fade out as they enter the Earth's shadow, may rhythmically vary in brightness as they spin and some satellites briefly 'flare' as their aerials and solar panels reflect sunlight, like mirrors.

On long exposure astronomical photographs satellites appear as white streaks (see above the page title). This can be a problem for astronomers and the nuisance has considerably increased with the launch of thousands of Starlink satellites by SpaceX.

By far the largest and therefore brightest satellite is the International Space Station (ISS) which has a precessing tilted orbit (imagine a wobbling hoop) that carries it over the UK on certain days. The next ISS pass over south Wales for the next 24 hours (where we are) is shown by the widget on the right. The ISS position in its orbit is shown at: http://www.isstracker.com/

ISS and other satellite passes can be found at: http://www.heavens-above.com/

NOTE that you need to enter your geographical position before getting the right results from this website, see the box top-right of the site page.

Long exposure showing the track of the ISS across the western sky in Monmouthshire. It fades leftwards as the space station enters the Earth's shadow. Picture by Keith Moseley