Tuesday, September 27, 2011

The Ellensburg sky for the week of 10/1/11

Saturday: Mnemonics are helpful for remembering astronomy facts. (Similarly, “Johnny Mnemonic”, the 1995 cyberpunk film, was helpful in getting Keanu Reeves’ career going.) After all, school children all around the country are learning the order of the planets by remembering, “My very excellent mother just served us nine….” Oops, I guess that one needs updating. Well, here’s one that will not need updating for nearly 100,000 years: the order of the stars in the Big Dipper. Because the nighttime stars are so far away from us, their actual motion through the sky, called their “proper motion” is not noticeable over even thousands of years. That is why the constellations have remained the same since ancient times. But two stars in the Big Dipper have a proper motion large enough such than in 100,000 years, the stars will no longer make a dipper shape. Until then, you can remember the names of the seven dipper stars in order from handle to cup by remembering this helpful advice for teens: “AM, ask mom. PM, dad”. The stars are Alkaid, Mizar, Alioth, Megrez, Phad, Merek, and Duhbe. Morning, morning, evening, death is one fist held upright and at arm’s length above the north horizon at 11 p.m.

Sunday: The increasing sunspot activity has led to prominent auroras in many northern states over the past week. The main cause of these auroras is electrically charged particles coming from the region of a sunspot that is over 10 Earth-diameter in length. (I guess it is more of a “sunstreak” than a sunspot.) For more information about sunspots, auroras and other space weather phenomenon, go to http://spaceweather.com/.
Monday: Jupiter is two fists above the east horizon at 10 p.m.

Tuesday: What do you like to look at in the night sky? Maria Von Trapp made her choice very clear in an earlier version of The Sound of Astronomy: “Light shining off of the moon and the rings, these are a few of my favorite things.” October 2010 to August 2012 is the Year of the Solar System. NASA is celebrating many solar system missions these 22 months, a Martian year. The Lunar Reconnaissance Orbiter is taking high resolution pictures of the Moon and Cassini has drastically updated what we know about Saturn. Saturn is still obscured by the glare of the Sun but the Moon is prominent in the night sky and waiting to be observed by you at an upcoming CWU Astronomy Club event. For more information about moons, rings, and the Year of the Solar System, go to http://goo.gl/jJOPF. For more information about the CWU event, read ahead.

Wednesday: At 6 a.m., Mars is four fists above the east-south east horizon, right in the middle of the constellation Cancer the Crab.

Thursday: Fomalhaut, the southernmost of the bright stars, is a little more than a fist above the south horizon at 10:30. It is in the constellation Piscis Austrinus or the southern fish.

Friday: Tomorrow is International Observe the Moon Night. But why wait? The CWU Astronomy club is having a Moon watching party tonight from 8:00 to 10:00 p.m. The event starts in Lind Hall room 215 with a brief presentation about the Moon followed by observing with the CWU observatory and other telescopes. Lind Hall is on the northwest corner of East University Way and Chestnut Street. Parking is free in all CWU lots after 4:30 p.m. For more information, go to http://goo.gl/jh3Zu.

The positional information in this column about stars and planets is typically accurate for the entire week.

Thursday, September 22, 2011

The Ellensburg sky for the week of 9/24/11

Saturday: “You know Aries and Cancer and Draco and Libra. Leo and Pisces and Virgo and Hydra. But, do you recall, the pointiest asterism of all? Triangulum, the three sided asterism, had a very pointy edge….” Sorry. Some stores have started putting up their Christmas decorations and that has put me in the mood to modify some Christmas songs. Anyway, Triangulum is a small constellation between the more prominent Andromeda and Aries. Its main feature is a skinny triangle oriented parallel to and nearly four fists held upright and at arm’s length above the east horizon at 10 p.m.

Sunday: Regulus is a fist to the upper left of the Moon at 6 a.m.

Monday: Did you time the exact length of the day and night last Wednesday on the first day of autumn? They were not equal in duration. Many people think that the day and night are the same duration on the autumnal equinox. The day is a little longer than the night for two reasons. First, the Sun is an extended object so even when the middle part has set, the upper half is still above the horizon lighting the sky. The second, and more influential reason, is that the atmosphere acts like a lens, bending light from the Sun above the horizon when the Sun is really still below the horizon. Day and night are closest in duration today.

Tuesday: This is the best week of the year to see Uranus, the seventh planet from the Sun. But you’ll need binoculars to find it. First, find Deneb Kaitos, a star one fist above the southwest horizon at 10 p.m. This star, whose name means “whale’s tail”, is about the same brightness as the Big Dipper stars. Another fist up is a reddish star called Iota Ceti. Put this star in the bottom of your binoculars’ field of view. At the top of the field of view should be a skinny, upright rectangle. Move the upper left corner of this rectangle to the lower right hand portion of your binoculars’ field of view. Uranus is a bluish dot near the middle of the field of view.

Wednesday: The west-southwest horizon is crowded just after sunset. Spica is about a fist to the upper right of the Moon at 7 p.m. The much brighter Venus is another fist to the right of Spica. Finally, Saturn is about a finger width above Venus.

Thursday: The cloudy season is coming to Ellensburg. Don’t feel bad. According to three astronomers, it is always cloudy season on HD 85512b, a newly discovered planet orbiting the star called… wait for it… wait for it… called HD 85512. These astronomers developed a method to estimate the cloud cover on planets orbiting distant stars. They think HD 85512b may be cloudy enough to have liquid water on its surface even though it is fairly close to its host star. While the presence of surface water does not guarantee finding life, it is a critical component. For more information, go to http://goo.gl/bGxMD.

Friday: Jupiter is two fists above the east horizon at 10 p.m.

The positional information in this column about stars and planets is typically accurate for the entire week.

Wednesday, September 14, 2011

The Ellensburg sky for the week of 9/17/11

Saturday: Last Friday, I gave you a very brief overview of how to use the Big Dipper as a clock. But, my explanation was helpful only for a late evening in the autumn or spring. Some of you go out other times of the year and need a way to tell time then. First, find the two stars at the far end of the Big Dipper cup, the stars that do not touch the handle. Draw an imaginary line segment starting at the North Star and passing through the two Big Dipper cup stars. Now, draw a big circle around the North Star. Your circle is a 24-hour clock. Number the circle from 0 hours at the top, counterclockwise to 12 hours at the bottom of the circle, and back up to 24 hours at the top. (O hours and 24 hours are the same on this clock because the day is 24 hours long.) The hour number on the big circle closest to where your imaginary line intersects this circle is called your raw time. Due to the location of the Big Dipper compared to the rest of the stars, the time nearest the intersection (the raw time) is correct for March 6. For any other night, subtract two times the number of months the current date is after March 6 from the raw time. For example, let’s say the imaginary line between the North Star and the Dipper stars is pointed to the right. That means the raw time is 18 hours or 6 p.m. If you made this observation on October 6, which is seven months after March 6, you would subtract two times seven or 14 hours from the raw time. Thus, the time for November 6 is 18 hours minus 14 hours or 4 hours. In other words, 4 a.m. Don’t forget to convert for daylight savings time if needed. For a more complete set of instructions, go to http://goo.gl/02HmA. There is a simple “star clock” template and instructions at http://goo.gl/SFKrE. Use this paper star clock whenever you watch is broken.

Sunday: Let me tell you the story of the ghostly white figure that rises early in the morning around Halloween. It appears to be a huge dim glow of white light that rises up from the east in the pre-dawn sky. No, I’m not writing about the ROTC student who has her first early morning physical training. I’m describing an effect called the zodiacal light. This light comes from sunlight reflecting off dust grains in our solar system. The effect is the most visible when the band of constellations called the zodiac makes a steep angle with the horizon. You need a clear sky with no haze or light pollution to see the zodiacal light that will be visible for the next week or so. At its brightest, the zodiacal light rivals the light of the central Milky Way.

Monday: Jupiter is a fist held upright and at arm’s length above the east horizon at 10 p.m.

Tuesday: This morning’s last quarter Moon is in the constellation Taurus the bull. This morning’s other Moon is…. Wait a minute. The Earth has only one Moon. True. And it has always had only one Moon. Not necessarily true. According to the best existing model, about four billion years ago, a Mars-sized object collided with the young Earth. The resulting debris coalesced to form the Moon. However, this model left a mystery: why is the Moon so asymmetric? Hardened-lava lowlands dominate the near side while the far side is dominated by mountainous highlands. According to a recent revision of the prevailing model, the early collision formed a large Moon and a small Moon. Over the years, the small Moon caught up to and collided with the large Moon. The highlands are the material from the collided small Moon. For more information about this theory, go to http://goo.gl/6JlcA.

Wednesday: The bright star Vega is nearly straight overhead at 8 p.m.

Thursday: Mars is four fists above the east horizon and one fist to the lower left of the Moon at 6 a.m.

Friday: At precisely 1:06 a.m., the center of the Sun crosses the celestial equator and passes into the southern sky. The celestial equator is an imaginary line that divides the sky into a northern and southern half. When the Sun is in the southern half of the sky, it appears to take a shorter path from rising to setting. It also does not get as high in the sky at noon. This leads to shorter days and longer nights. Since the Sun crosses the celestial equator today, there is an instant when it is equally in the northern and southern sky, called the north and south celestial hemispheres. This so-called “equal night” is given by the Latin word equinox. Thus, today is known as the Autumnal Equinox. However, the day and night are not of equal duration today. The sun rises at 6:50 a.m. and sets at 6:58 p.m. Day and night are closest to equal duration next Monday.

The positional information in this column about stars and planets is typically accurate for the entire week.

Wednesday, September 7, 2011

The Ellensburg sky for the week of 9/10/11

Saturday: The violent death of lots of aliens is called a video game. The violent death of a supergiant star is called a supernova. On August 24, a star in the Pinwheel Galaxy, a mere 21 million light years away, went supernova. This is the closest and brightest supernova in the past 25 years. You’ll need binoculars or a small telescope to see it. First find the Big Dipper handle, about two fists held upright and at arm’s length, above the north-northwest horizon at 11 p.m. The galaxy is about a half a fist above the end star. There is a very helpful map at the bottom of this page http://goo.gl/Mw2LO.

Sunday: Shine on, shine on harvest moon, up in the sky. It’s just like a full moon in January, February, June and July. The only difference is that near the Autumnal Equinox (also known as the first day of fall), the full moon rises near sunset resulting in a full night of light for the harvest. The harvest moon looks like a dull orange color while it is near the horizon because of the dust kicked up from the harvest. The dust scatters the white light reflecting off of the Moon resulting in slightly more of the red and orange components of the white light reaching your eyes. Although the Moon has a dull yellow color whenever it is near the horizon owing to light scattering off of dust and atmospheric particles, the effect is more noticeable for the harvest Moon. Tonight’s full moon, which isn’t completely full until tomorrow at 1:30 a.m., is in the constellation Aquarius the water bearer.

Monday: Science is Central! This week, faculty, staff, and students in the College of the Sciences at CWU will kick off the start of the academic year by hosting a series of evening science lectures and demonstrations geared for all ages. All events are taking place on the CWU Ellensburg campus and all are free. The series kicks off tonight when Ton Cottrell shares photos, stories and thoughts from Northern Alaska from 7:00 – 8:00 pm in Science room 101 followed by a guided tour of the night sky with several telescopes. Check http://goo.gl/5Hi5y for an event schedule.

Tuesday: In most parts of the country, a mixture of tasty carbon-based material and healthy minerals is called a casserole. In Minnesota, it is called a hot dish. (Uffdah, you betcha!) In space, it is called a supergiant. Antares, a supergiant in the constellation Scorpius, is forging lighter elements into carbon, oxygen, silicon, and iron in its core. It is on the main course table one fist above the southwest horizon at 7:30. Make sure it cools off before you take a bite.

Wednesday: “One world, group hug, love everyone” philosophy: political borders are human-made and can’t be seen from space. Real world, pragmatic discovery: some human-made political borders CAN be seen from space. Since 2003, India has illuminated its border with Pakistan to prevent illegal crossings. In August, astronaut Ron Garan took a picture of the boarder from the International Space Station. For more information, including the photo, go to http://goo.gl/mY8xG.

Thursday: Jupiter is about a half a fist below the Moon at 10 p.m.

Friday: You can use the position of the Big Dipper as a clock. During the late evening in the autumn, the Big Dipper cup is facing up to hold water. During the late evening in the spring, the Big Dipper cup is facing down to produce those spring showers. The water-holding Big Dipper is one fist above the north horizon at 11 p.m.

The positional information in this column about stars and planets is typically accurate for the entire week.