On several occasions we’ve talked about what happens when the International Space Station (ISS) enters Earth’s shadow. Not only does it fade away as you’d expect, but it also changes color. To my eye, the ISS looks yellow, a color imparted to the flying bird by its solar panels. But as it treks into Earth’s shadow you can see the station change from yellow to orange to red as it scurries from daylight to sunset to night.
I used to think this multicolor sunset display was only visible in binoculars. This past Saturday night I was pleasantly surprise to see it with the unaided eye. That’s because the ISS made a high pass and began fading when nearly overhead.
A rule of thumb about satellites – the higher up they are, the closer they are to the observer. And the closer something is to you in the sky, the brighter it is. That’s why I could see color all the way into the shadow’s edge as the ISS faded. Meanwhile the astronauts got to watch one of 16 sunsets they see every time they orbit Earth.
See the sun set on the big bird yourself by logging in to Heavens Above and selecting your city. When you click the ISS link, you’ll be shown a list of dates when the station passes across your sky. Click on the date link and it will take you to a map of the station’s path that particular evening. You can tell when the ISS will enter Earth’s shadow – the path shown will come to an end while it’s still well up in the sky. These are the passes to watch for. Bring binoculars to see the color better.
While we’re on the topic of sunsets, this will be the last good week all season for northern hemisphere sky watchers to catch the planet Mercury after sunset. Look for it low in the northwestern sky about 40 minutes after sunset. Help in the form of a fingernail crescent moon arrives this Thursday. Use the moon to point you to the planet. Although Mercury will be near the stars Castor and Pollux in Gemini, it will be considerably brighter and stand out better in twilight.
Christopher Go of Cebu City in the Philippines got his first pictures of Jupiter in morning twilight this season on June 18. Although they’re soft because of the planet’s low altitude and atmospheric turbulence, they show a lot of changes happening in the planet’s North Equatorial cloud belt (NEB). The NEB and South Equatorial belt (SEB) are the two big, dark “stripes” crossing the planet that are visible in even small telescopes. Especially interesting is the large red feature – not a spot like the famous Great Red Spot in Jupiter’s southern hemisphere – but colorful just the same.
I love following extraterrestrial weather. Seeing Chris’s images has me thinking it’s probably time to set the alarm for a 4:30 a.m. session with Jove. If you’re interested in tracking Jupiter’s cloudy fits, you’ll find the planet low in the northeastern sky 40 minutes before sunrise.