Pile it on! Comet NEOWISE, Jupiter and Saturn and now the International Space Station (ISS). You may have already noticed the station cutting across the night sky over the past few nights while you were you out comet-watching. It’s that extremely bright “light” moving from west to east, taking about 5-6 minutes to cross the entire sky. Through early August, observers in mid-northern latitudes can watch anywhere from 2 to 5 passes over a single 24-hour period about an hour and a half apart.
Each year on either side of the summer solstice in either hemisphere, the space station’s orbit and Earth’s day–night terminator (the line that separates day and night) nearly align. Like seeing the “midnight Sun” at the Arctic Circle on the first day of summer, astronauts and their craft bask in sunlight 24/7. Some skywatchers stay up all night to see every pass in what’s dubbed an ISS Marathon. Nothing’s required except the ability to remain awake and see all ISS flyovers during a 24-hour period. For my city, July 17 fits the bill with 5 passes: 12:15 a.m., 1:52 a.m., 3:28 a.m., 9:49 p.m. and 11:26 p.m. Maybe next year we’ll do T-shirts.
You can plan your own marathon by going to Heavens Above and clicking on the blue link Change your observing location (if you haven’t already added it before). Then find your city, add it and you’re set. Next, return to the opening page and click the ISS link. You’ll see a list of passes for the next 10 days. Details for each pass include start time, altitude (45° is halfway up the sky), direction to look and end time. Click on any line and it will link to a map showing the space station’s path across the sky for that particular flyover. All times shown are local times for your location.
The space station is consistently the brightest artificial satellite in the sky because it’s also the largest. If you have a telescope try to manually track it using a low magnification of 40-70x. Note its direction of travel and then point the scope slightly ahead of its position and watch for this big bird to fly through your eyepiece. Once you’re successful, move the scope to follow the ISS and enjoy the sight. You won’t believe your eyes because you can actually see a shape and details like the orange solar panels. No kidding.
We talked about Jupiter yesterday. I noticed it beaming brightly last night. In contrast the comet looks big and foggy, except for its bright head, similar to the appearance of the Milky Way. I swatted a lot of mosquitos while photographing NEOWISE from Duluth’s Park Point, a large, populated sandbar that extends from the downtown and wraps along the far western edge of Lake Superior.
Because of light pollution the comet wasn’t as pretty from the city as the country, but it was still easy to see with the unaided eye and a sweet sight in binoculars. Despite fading a bit NEOWISE shows no other signs of weakening and remains a magnificent sight from a dark sky. The moon will return to brighten the evening sky about July 23 so we have about a week of true darkness left to relish this celestial spectacle before it’s compromised by moonlight.
NEOWISE is easy to find using the Big Dipper. Go out about an hour and a half after sunset (around 10 to 10:30 from many locations) and look about one fist up (10°) in the northwestern sky. The head of the comet and a bit of the tail are visible in twilight, but the full glory of the tail won’t be seen until darkness sets in.