Skywatch for the week of August 8, 2022
Mon Aug 8, 2022 GALILEO’S FIRST TELESCOPE
On August 8th, 1609, members of the Venetian senate climbed to the top of the tower of St. Mark’s Cathedral for a demonstration of Galileo’s first telescope. The senators viewed ships far out at sea, ships that couldn’t be seen by the naked eye for another two hours. What a marvelous invention! Galileo’s salary at the University of Padua was immediately doubled. Now if you were to buy today the cheapest, crummiest telescope you could find, it would still be better than that first one. Galileo did not invent the telescope; but after hearing reports of its invention made one of his own. It was what he did with the telescope that made the difference. Instead of looking at ships out at sea, he turned the telescope skyward, and wrote about the moon, the planets and the stars - all the marvelous things in the heavens.
Tue Aug 9, 2022 THE “TEARS OF ST. LAWRENCE”
Every year at this time, the earth travels through a part of its orbit that’s littered with bits of comet dust. As we plow into this region, we’re treated to a display of shooting stars, when those particles plunge through our atmosphere. The ice and dust are vaporized, lighting up the sky in brief flashes of light – meteors. This particular meteor shower is called the Perseids, so named because they seem to come out of the part of the sky near the constellation Perseus; it’s a reliable shower viewed by millions of people for many years: in medieval times it was known as the “tears of St. Lawrence,” in honor of the Christian martyr whose feast day is tomorrow, August 10th. Go outside when the moon sets after midnight, face east, and look up toward the top of a clear, dark sky for the best views.
Wed Aug 10, 2022 LAST GOOD NIGHT FOR PERSEIDS
The Perseid meteor shower is reaching peak activity over the next two nights, but the bright light of the nearly full moon will make it hard to see these shooting stars. The waxing gibbous moon will be shining in our sky for most of the night, but when it sets an hour or so before sunrise we should have our best chance to see the meteors.
Dress warmly, protect yourself against mosquitoes, find a safe spot that’s away from bright streetlights. Bring a lounge chair that lets you lean all the way back, and of course refreshments such as iced tea and chocolate chip cookies, are always welcome. Meteor showers are fun, but you can go for several minutes before spotting one. And if it’s cloudy you won’t be able to see them. Face east and look toward the top of the sky for best results.
Thu Aug 11, 2022 MAGELLAN REACHES VENUS
On August 10th, 1990 the Magellan Spacecraft reached Venus. It orbited our sister planet for four years, allowing its radar to penetrate the thick clouds, which let us see its volcanic mountains, its meteor impact craters, and also some very strange circular features called coronae, which we think may be collapsed volcanoes, something we never saw anywhere else in the solar system. 85% of Venus’ surface seems to be covered in lava flows which probably happened within the past million years, which is fairly recent on a geologic time scale. The Magellan spacecraft is gone now; it was sent to its destruction in October 1994, when it was plunged into the thick Venusian atmosphere. But Venus is still with us, now visible as a brilliant star-like object above the eastern horizon before sunrise.
Fri Aug 12, 2022 AUGUST FULL MOON
The moon is full this weekend. Colonial Americans knew this as the Dog Days moon; ancient Celts called it the Dispute Moon. The Sioux Indians say that this is the Moon When the Geese Shed Their Feathers. The Ottawa tribes know it as the Sturgeon Moon, named for the misty moon-bow made by that fish when it leaps from the stream. The Ponca call it the Corn is in the Silk Moon, meaning it's a good time to harvest the corn; other tribes have names like the Big Ripening Moon of the Creek and Seminole Indians or the even more simply named Corn Moon of the Zuni. The Choctaw refer to this as Women’s Moon, and it’s true that the moon’s features suggest to many the profile of a woman’s head – the lady in the moon. However, I’m going to call this the I Can’t See the Meteors Moon, since its bright light will wash out the Perseid meteor shower, now at peak activity.