Sep 2018

• Attendance: 16 people in attendance including three visitors--Bob and Glenda Bolinger and Derek’s dad Will

• Financials:

Beginning balance August 1 $2,739.24

2 new members incl. 1 family

Paid liability insurance $320.00

Ending balance $2,474.24

• Star party Sept. 14 at the Bolingers’ ranch 10 miles east of town toward Nowata. Their far has good views to the north and south, and a fire pit! Room enough on a recent trial visit to set up 4 tripods easily.

• Start planning recurring start parties at Osage Hills State Park? John Blaesi and others looking into this. Another possible area to have a star party is Dinosaur Park.

• If you have photos to send to the club, can put them in online photo storage on Flickr and Google Groups that we have.

• The fall 2018 TU Presidential Lecture Series on October 2 at the University of Tulsa features author Janna Levin, professor of physics and astronomy at Barnard College of Columbia University. The presentation will take place at 7:30 pm in the Reynolds Center and is free and open to the public. Her presentation topic is Black Hole Blues.

John Blaesi did a brief presentation on types of twilight:

Civil—can still “play ball”

Astronomical—can start to see stars

Nautical—can see navigational stars that are used with a sextant and the horizon to get bearings

Main presentation by Denise on Meteor Showers:

Watched National Geographic video on Meteors 101 (available on YouTube)

Basics of Meteors, Meteorites and Meteor Showers

• These are all space rocks

• Largest space rocks are asteroids, which are minor planets that orbit the Sun

• Over time, asteroids break down into smaller particles of rock called meteoroids. These also orbit the Sun.

• Meteoroids are also chips knocked off other minor planets or debris from comets.

• Some meteoroids appear to be material blasted off the Moon and Mars.

• When a meteoroid enters the Earth’s atmosphere and vaporizes, it’s called a meteor, or shooting star. The meteor heats up and makes the air around it glow. (The flash of light itself is called the “meteor”.) We see a meteor as a streak of light. Most meteors burn up.

• Meteors were long thought to be bursts of hot gases high in the atmosphere. The name “meteor” is derived from the same root that gives us the term “meteorology”, but meteors are actually unrelated to weather on Earth.

• Very bright streaks may be caused by meteoroids the size of a pea or marble.

• There was a very bright shooting star on August 27 at 8:40 pm that has been documented as having been seen in a number of states, including Oklahoma. I saw it!

• Once or twice a year, somewhere on Earth, a very bright meteor, called a Bolide or fireball, is seen. These are sometimes bright enough to be visible in daylight, often produce a rumbling sound and leave behind a dust trail in the atmosphere that lasts for hours. Fireballs seen at night have sometimes been described as bright enough to read by. (The shooting star on August 27 wasn’t one of these.)

• Scientists think up to 10,000 tons of meteoroids fall to Earth every day, but most are no bigger than a speck of dust and burn up.

• If a meteor enters the Earth’s atmosphere and reaches the Earth’s surface without burning up, it’s called a meteorite. Meteorites range in size from tiny pebbles to boulders.

• Some planets and moons don’t have enough atmosphere to protect them against meteor and asteroid impacts. Our Moon, Mercury and Mars are covered with round impact craters from these collisions.

• But even those like Earth that do have enough atmosphere to protect against smaller ones can’t handle the bigger ones!

Some history on knowledge of meteorites:

• Most people gave no credit to the idea that stones fall from the sky until the beginning of the 19^th century.

• Probably the earliest mention of such stones occurs in a Chinese manuscript from about 644 B.C.

• Greek and Roman authors also refer to such falls.

• Some observers confused falling meteorites with hail.

• The first real scientific study of a fall of meteorites came in 1803, when thousands of stones fell on France and were studied by astronomer Jean-Baptiste Biot.

• A woman in Alabama was hit by a meteorite when one crashed through the roof of her home in 1954.

• In 1971 a meteorite smashed into a home in Wethersfield, Connecticut. Eleven years later another home in the same town was struck by a meteorite.

• And a very large meteorite (or asteroid) is responsible for the extinction of the dinosaurs and marks the boundary between the Cretaceous and Tertiary periods in our geologic history.

What are meteor showers?

• We see meteor showers, or shooting stars, when the Earth travels through clouds of particles left by asteroids or comets.

• (Meteoroids produced by fragmentation of minor planets are randomly distributed and therefore come from any direction in space, at any time.)

• By contrast, meteoroids that follow comets’ orbits behave like miniature planets with predictable paths.

• If Earth regularly crosses a comet’s orbit, once or twice a year it will get hit by a swarm of meteoroids all arriving out the same point in the sky. This swarm is called a meteor shower.

• This single point in the sky is called the “radiant”. Meteors seen near the radiant are approaching the observer and will appear as short streaks in the sky.

• Meteor showers can be caused by the orbit of an “extinct” comet that has long since evaporated but left behind a swarm of meteoroids that have kept the same orbital path.

Basics of meteor showers

• Meteors seen 45 to 135 degrees from the radiant are moving in a more parallel direction to the observer. These meteors will produce longer streaks in the sky. These can be closer to the horizon and run mostly parallel to it; I call these “grounders”.

• Meteor showers are usually named for the constellation in which their radiant lies at the time of the shower maximum. For example, the Perseid meteor shower appears to come from the constellation Perseus.

• Since the Earth’s orbit is similar enough from year to year, the showers are predictable.

Meteor shower viewing tips:

• You’ll see the most meteors on a clear, dark night during a new Moon.

• If you live near a brightly lit city, drive away from the lights and toward the constellation from which the meteors will appear to radiate.

• To see the most meteors, watch as late in the night time as you can, up until dawn.

• To view a meteor shower, the meteor shower radiant must be above the horizon—most radiants are up by midnight.

• Where to look? The best place to start is between the radiant and the zenith (straight above you).

• The “best” viewing times are usually predawn and late evening. In nearly all showers, the radiant is highest just before dawn. (The Geminid meteor showers are visible all night long, since Gemini arises just an hour or two after nightfall; the radiant is highest a little after midnight.)

• Starting around midnight, your location on the globe spins around to the forward-facing half of Earth (in relation to the direction of orbit). At dawn, your location on the globe directly faces the direction in which Earth is traveling along its orbit. So between midnight and dawn, you’ll be viewing the meteors head-on, for a more frequent display.

• What time during the year to look for a particular meteor shower? The time of the year for each shower is determined by when the Earth’s orbit crosses the stream of meteoroids. On the list we’re going to look at, the peak date shows when meteor showers will be the strongest.

• You don’t need any special equipment. In fact, binoculars do not work for meteor showers. The naked eye is best. Most meteors flash by in a second or less.

• Note that fireflies in summer can be mistaken for meteors!

• Spread a blanket on the ground and look up into the dark night sky. (Or sit in a chaise lounge or lawn chair if there might be creepy crawlies!)

• Sporadic meteors (unrelated to a shower and commonly called shooting stars) can be seen on any night, but increase in frequency after midnight and peak just before dawn. (The one on August 27 was early evening.)

When are meteor showers? Interspersed throughout the year!

The list we’re going to review is from the all-time standby, the Farmer’s Almanac…plus EarthSky network and other sources.

• “Peak dates” may vary by one or two dates.

• “Predawn” means an hour or so before morning twilight. Usually a good time to see most meteor showers is after 2 a.m. and the best time is about an hour or so before morning twilight.

• January: Quadrantids. Peak date January 3-4, predawn, look to N/NE. No associated comet, radiate from northern section of constellation Boötes. Radiant near the Big Dipper asterism in the N/NE sky after midnight and highest up before dawn. Up to 25 meteors/hour if in rural area on a moonless night. Overall lasts about 2.2 days.

• April: Lyrids. Peak date April 22, predawn, look to NE. Associated comet Thatcher, radiates from constellation Lyra, near bright star Vega. Vega rises in the NE about 10 pm on April evenings. Up to 10 meteors/hour, rural area, no moonlight. Overall lasts from about April 16 to April 25.

• May: Eta Aquariids. Peak date May 4, predawn, look to S. Associated comet Halley, radiate from constellation Aquarius. Up to 10 meteors per hour if in rural area on a moonless night. Overall lasts about 6 days. The shower takes its name from the star Skat, also known by its Greek name of Delta Aquarii. The meteors appear to originate from a point near this star.

• July: Delta Aquariids. Peak date July 30, predawn, look to S. No associated comet, radiate from Aquarius. Up to 10 meteors per hour in rural area, moonless night. Overall lasts about 14 days.

• August: Perseids. Peak dates August 11-13, predawn, look to NE. Associated comet Swift-Tuttle, radiate from constellation Perseus. Up to 50 meteors/hour in rural area, moonless night. Overall lasts about 4.6 days.

• October: Draconids. Peak day October 9, late evening, 10 pm-midnight or a little past. Look to NW. Associated comet Giacobini-Zinner, radiates from constellation Draco. Up to 6 meteors per hour, rural area, moonless night. Sometimes Draconids may be visible at nightfall through early evening.

• October: Orionids. Peak dates October 21- 22, predawn. Look to S. Associated comet Halley, radiate from the club of constellation Orion, north of the bright, ruddy star Betelgeuse. Up to 15 meteors/hour, rural area, no moonlight. Overall lasts about 4 days.

• November: Taurids. Peak date November 9, late evening, 10 pm-midnight or little past. Associated comet Encke, radiate from constellation Taurus. Up to 3 meteors/hour, rural area, no moonlight.

• November: Leonids. Peak dates November 17-18, predawn, look to S. Associated comet Tempel-Tuttle, radiate from constellation Leo. Up to 10 meteors/hour, rural, no moon.

• November: Andromedids. Peak dates November 25-27, late evening 10 pm-midnight or little after. Look to S. Associated comet Biela, radiate from constellation Andromeda. Up to 5 meteors/hour, rural, no moonlight.

• December: Geminids. Peak dates December 13-14, all night. Look to S/SE. No associated comet, radiate from constellation Gemini. Up to 50 meteors/hour, rural area, no moonlight. Geminids can been seen starting around 9-10 pm until morning twilight. Overall lasts about 5.2 days.

• December: Ursids. Peak date December 22, predawn. Look to N. Associated comet Tuttle, radiate from constellation Ursa Minor. Up to 5 meteors/hour, rural, no moonlight. Overall lasts about 4 days.

Rocky Mountain High

• In 1985, John Denver spoke of the genesis of Rocky Mountain High. He told of the elation, celebration of life or joy in living that one feels when observing something as wondrous as the Perseid meteor shower on a moonless, cloudless night, when there are so many stars that you have a shadow from the starlight, and you are out camping with your friends, your best friends, and introducing them to one of nature’s most spectacular light shows for the first time.

Then watched a video of Perseids and one of Lyrids (available on YouTube)