Hello, fellow stargazers!
Fall is officially here and every day we can appreciate the color change that comes with the season. The nights are quite cool and have been clear, which makes for great night sky observing.
Now is the time to go out and enjoy what the sky offers. Soon it will require really bundling up for the cold weather!
The moon was Full on the 27th, and hopefully you got a chance to see a Harvest, Blood Moon during a lunar eclipse! Pretty spectacular and not common to have all three special lunar “events” fall on the same day!
Now is a good time to go out and appreciate how the constellations we have all become familiar with are sinking into the west rather early, usually right after sunset.
The Big Dipper is closer to the northwest horizon in the early evening as well, however, it never completely disappears.
The constellations around Polaris, the north star, are called circumpolar, which means they will revolve around celestial north but are always visible. These include Perseus, Andromeda, Cassiopeia, Cepheus, Camelopardis, Draco, and the Big and Little Dippers. Some don’t sound familiar, but I suggest you consult your planetarium program or star atlas. Remember, Stellarium is a great and FREE planetarium program (www.stellarium.org) for the PC that is easy to use.
Turn your attention to the constellation of Perseus in the northern sky. As you may remember, Perseus in Greek mythology slew the monster that was about to eat the lovely Princess Andromeda. He did this by first beheading the Medusa, whose glance would turn any living object to stone. He then used her severed head to turn the monster to stone at the last minute.
Perseus, Andromeda, and her parents, King Cepheus and Casseiopia, are all together in the northern sky.
Although Perseus is not particularly bright, it contains several fascinating objects, two of which we will discuss today.
The first is the famous Double Cluster in Perseus. Use your planetarium program to find this. Although naked eye visible, they are best seen with binoculars or a low power telescope.
Two glittering jewel boxes of stars, side by side—a magnificent site! They are about 7000 light years away, and separated from each by two hundred light years.
The other object is a most unusual star, called Algol, also called the Winking Demon Star. It represents the head of Medusa.
Why is it so unusual? It’s because every 68 hours it dims considerably and after a few hours, brightens back up again!
There are numerous references to it throughout history, and the spookiness of this unusual but very regular dimming is perfect for Halloween time! Why does this happen? This is because the Algol system is composed of two stars (actually a tiny third one also exists) that rotate around each other. Algol is eclipsed by the unseen companion every 67.75 hours. That means that for a few hours, the other dim star passes in front of our line of vision and blocks Algol’s light from reaching us. As it continues to orbit, Algol returns to its former brightness! This is visible naked eye, although a pair of binoculars helps to see it more easily.
This concept of eclipsing (where an object is blocked visually by another large object passing in front) is experienced in our solar system with lunar and solar eclipses.
If the passing object is very small, it’s called a transit, like the Venus transit in front of the sun last year.
On October 4, 1957 Russia launched Sputnik, a grapefruit sized satellite which was the first one ever launched. This set off the space race and was a backdrop to the Cold War tensions that existed at that time. The Russians also launched Luna 3 on October 7, 1959 and were the first to photograph the far side of the moon.
Our next NOMAC meeting is at 7:30PM on the NCMC campus in early October (check out our website at www.nomac.net for details). Until next week, clear skies and keep looking up!