Weekend Sky Report / Messier 15
November 29, 2019
First, what is a globular cluster? A globular cluster is a densely-packed group of stars bound by their own collective gravity. They form gradually—many of them over literally billions of years—pulling new stars in as they complete their orbits around their host galaxy. The globular we’re looking for tonight is Messier 15—also known as the Globular Cluster in Pegasus.
To find Pegasus, look high to the southwest around 8pm. Find the nose of Pegasus, the orange star Enif, which is also the brightest star in Pegasus. Then, through your telescope or binoculars, scan just to the right, and slightly downward. When you find what looks like a fuzzy star, you’ve found it. A 12 billion-year-old collection of well over 100,000 stars… that’s over 170 light-years across.
What sets Messier 15 apart from a lot of other globular clusters is that it’s theorized to have an intermediate-class black hole at its center. This type of black hole has only been discovered in the last 15 years. Before that, all we knew about were stellar-mass black holes—the small ones, and supermassive black holes—like those found at the center of galaxies. And while we don’t yet know for sure whether there’s one in Messier 15, it’ll be fun to ponder as you look at it tonight.
Mar 27, 2020
If we're lucky enough to get clear skies in the early morning--before 7am Eastern, look to the south and you'll see three bright points of light. From left-to-right, it's Saturn, Mars, and Jupiter.
Mar 20, 2020
The Beehive Cluster is right smack in the middle of Cancer the Crab, which is actually a very dim constellation.
Mar 13, 2020
Blue stars that are really close to red stars can appear to us as a greenish blue. One good example is Antares B, the binary companion to the red giant Antares A, the heart of Scorpius.
Feb 28, 2020
Leo sweeps across the southern sky all night this time of year. In the evening, it's to the east. To find it, look for the Big Dipper. It'll be straight up and down with the cup at the top. Connect the two stars at the top that make up the end of the cup, and from that straight line, extend the line to the right toward the east, and when you hit the bright star Regulus, you've arrived.
Feb 21, 2020
Every good hunter needs support. Orion and his two dogs have reigned the evening sky in the winter since before human civilization. One of the earliest representations of Orion appeared in cave art dated more than 32,000 years ago.
Feb 14, 2020
On Tuesday morning, February 18, 2020, just after 7am Eastern, Mars will disappear behind the moon. An event known as a lunar occultation.
Feb 07, 2020
Sirius is a binary system consisting of the very bright, main sequence stage star we can see with the naked eye, Sirius A, and a much smaller companion white dwarf stage star, Sirius B.
Jan 31, 2020
Venus is 15 times brighter than the brightest star in the night sky, Sirius. And planets don't twinkle like stars do.
Jan 24, 2020
The Triangulum Galaxy gets its name from the constellation where it's found. It's a small constellation and, as the name suggests... it's a triangle.
Jan 17, 2020
The Orion Nebula is just over 1300 light years from our solar system, and it's believed to be an enormous 24 light years across. Because it's so big, and... relatively close, it's easily visible with binoculars or a telescope, even under fairly bright, suburban skies.
Jan 10, 2020
looking at a full moon through a telescope, you notice a lot. The craters, the so-called "seas," the "Ocean of Storms-" that's the big sea... So just what are all those geographic features?
Jan 03, 2020
Around 9pm, look low to the southeast to find the brightest star in the night sky. Bright white, twinkling Sirius. Above it, you'll see that iconic winter constellation Orion the Hunter. The orange star at his shoulder is the red supergiant Betelgeuse. Draw a line between Sirius and Betelgeuse, then look to the left, or east to find Procyon (PRO-see-on), another bright white star, and there you have it. A large, nearly perfect equilateral triangle of bright evening stars.
Dec 27, 2019
Betelgeuse is one of the largest stars we've ever discovered. If you were to replace the sun with Betelgeuse, it would engulf all four inner planets from Mercury to Mars, and, by some estimates, even Jupiter.
Dec 20, 2019
At 2300 light years away, the cluster resembles an upside-down Christmas tree with the brightest star representing the base of the tree. The other stars form a loose cone shape that makes it look like Christmas tree lights.
Dec 13, 2019
Auriga is home to three Messier objects, named after 18th century French astronomer Charles Messier, famous for his catalog of deep-sky objects. The three objects are all open clusters, which can be seen through most backyard telescopes.
Dec 09, 2019
The three stars that make up Orion's belt is the giveaway. But there's a lot more to appreciate.
Nov 22, 2019
Lots of people can see just those three stars of Orion's belt and know what they're looking at. But look a little closer at the belt with a telescope, or even a good pair of binoculars, and you'll see many more stars.
Nov 15, 2019
There was a full moon this past Tuesday, which means this weekend the moon is in the waning gibbous phase. Waning moons are out in the morning, and this week's mostly clear skies have given us a good view--particularly those of us who drive west into work. If we get clear skies this weekend, take a moment to look west at the gibbous moon.