The International Space Station (ISS) shows as a trail of light as it passes over northern Minnesota Friday morning. This coming week the station will continue making mulitple passes over the U.S. during the early morning hours. Photo: Bob King
Summer nights are sure short. Back in the winter, the ISS would make passes over the region around 6 a.m., a time more of us were likely to be up and around. Now because of early sunrises, those flybys occur during the very wee hours of 2 and 3 a.m.
Still, if you happen to be up late, it’s nice to know you’re in the company of the astronauts. Here are times to spot the ISS in the coming week. Except where noted, all passes begin in the west or southwest with the station moving eastward across the northern sky. Look for a bright, moving "star".
Sun. June 28 beginning at 3:32 a.m. Brilliant flyby!
Mon. June 29 at 2:24 (appears high in the east) and 3:56 a.m. Earlier flyby a bright one.
Tues. June 30 at 2:47 and 4:21 a.m. " "
Weds. July 1 at 3:10 and 4:46 a.m.
Thurs. July 2 at 2:02 and 3:35 a.m. " "
Fri. July 3 at 2:25 and 4 a.m.
Sat. July 4 at 1:16 (appears due north), 2:49 and 4:24 a.m. " "
This map shows the sky as you look south about two hours after sunset when twilight has ended. The four "M" objects shown are all visible in binoculars while three of them, M8, M6 and M7 can even be seen with the naked from a dark sky site. Created with Stellarium.
The forecast may look bleak for tonight but soon the sky will clear again. When it does, I hope you can find a place with a wide open view toward the southern horizon because the richest part of the summer Milky Way awaits you there. When you look into the tail of the scorpion and further east into Sagittarius the Archer, you’re gazing toward the center of the galaxy. Though the center itself is obscured by countless clouds of cosmic dust, the entire region is thronged with globular star clusters, cloudy nebulas and open clusters. We’ve looked at a few of these over the past few weeks but now it’s time to unload the full cart of bananas.
A time exposure photo from two nights ago shows the same slice of sky as in the map above. I’ve added constellation outlines and the names of our featured binocular objects. The cloudy glow at left is the Milky Way while city light pollution lights up the lower right. Despite its low altitude from Duluth, M7 is easily visible with the naked eye. Both it and M6 are tucked are just above the scorpion’s tail. Photo: Bob King
All four of our featured deep sky objects start with the letter "M" because they were all cataloged more than two centuries ago by French astronomer and comet hunter Charles Messier. Since then, a few of the brightest or most distinctive-shaped ones have acquired nicknames. M8 is called the "Lagoon Nebula" because dark rivers of dust ply its nebulous confines. M7 goes by the "Butterfly Cluster" because the stars are arranged in a way that suggests the outline of a butterfly.
You can make out the vertical bar of stars in the cluster M4 (left) and see one of the dark, dusty rivers in M8 (right). Globular clusters are highly compressed balls of hundreds of thousands of stars. Open clusters, like the little group of blue stars in the left side of M8, are looser. Photos: Jim Misti
So now that you have a good view southward and you’re observing from a reasonably dark place, point your binoculars at M4, a big globular cluster very near the bright star Antares (an-TAR-eez). Look for a softly glowing spot that looks totally unlike the sharp form of a star. M4 is a mere 7,200 light years from Earth and one of the closest globulars in the sky. That also makes it one of the few such clusters that you can resolve into individual stars in a small telescope. While you’re at it, look for one of M4′s peculiar features, a straight bar of stars that cuts vertically across its center.
M7 and M6 are both open clusters, which like the globulars, feel one another’s gravity and travel as a unit through space together. Unlike globulars, they’re much looser and contain far fewer stars. Open clusters are young groups of stars that hang out in the flat disk of the galaxy; ancient globulars reside in a great halo centered on the galaxy’s core.
The clusters M6 (left) and M7 in the constellation Scorpius. M6 is shaped like a butterfly while M7 looks like the letter K to me. Credit: M6 by Ole Nielsen; M7 by N.A.Sharp, REU program/NOAO/AURA/NSF
Two nights ago M7 was easy to see even though it was only a fist high in the south. It looked like a small chunk of the Milky Way. My 10×50 binoculars had no problem resolving much of it into stars. M6 is smaller, fainter and more star-like with the naked eye but an easy sight in binoculars. You’ll need a small telescope to see its remarkable butterfly shape. M6 is some 1600 light years away and about 25 light years across. M7 is about the same size but closer at 1000 light years.
That brings us finally to M8, a combination nebula and star cluster. The cloudy part consists of dust and gas that’s in the process of congealing into new stars. As if to prove the point, the little cluster embedded in the west side of the nebula was actually formed from material in the Lagoon. You can’t miss M8 in binoculars — it’s an elongated puffy spot with a bit of sparkle to it from the cluster.
Northern hemisphere summers have everything, from a million living things to the richest presentation of galactic treasures this side of Andromeda.