By Will Collette
See this video on YouTube here: https://www.youtube.com/watch?v=nShmgRiAKFU
Due to celestial mechanics, six minutes seems to be the longest possible overpass by the International Space Station over Charlestown. We can see it only when its path lines up with the sun's rays which are then reflected down to us. That's why all passes visible to the naked eye occur just after the sun sets or just before sun rise.
Tonight, according to the National Weather Service, it will be "mostly cloudy" but clearing. But it may be better than that, given that we now have clear skies when we were supposed to have clouds.
If it stays this way, viewing should be fine.
About the only human space exploration left is the International Space Station. While we wait for humanity to once again reach for the stars, we get to see the ISS serenely cross our skies on occasion when timing, their orbital path and the weather cooperate.
The station will be visible for six minutes beginning at 4:47 PM with the ISS appearing at around 10 degrees off the horizon in the northwest. Its arc will take it to 69 degrees over the horizon as it crosses the sky to 59 degrees above the horizon in the east southeast where it will seem to vanish.
We can see the ISS shortly after sunset and also shortly before dawn when the sun's rays hit it just right.
Official message from NASA: Time: Mon Dec 19 4:47 PM, Visible: 6 min, Max Height: 69°, Appears: 10° above NW, Disappears: 11° above ESE
I get e-mails from NASA with notice of these ISS overflights over Charlestown.
You can sign up to get those e-mails here.