Thursday, January 12, 2017

The Ellensburg WA sky for the week of 1/14/17


Saturday: Who can forget that memorable song by Three Dog Constellations Night, “The sky is black. The stars are white. Together we learn to find the light.” Well, maybe it didn’t go like that. Which is good. Because not all stars are white. Most stars are too dim to notice a color. But, two of the stars in the constellation Orion provide a noticeable contrast with each other. Betelgeuse, five fists held upright and at arm’s length above the south horizon at 10:30 p.m. is a red giant. Rigel, the bright star about two fists to the lower right of Betelgeuse, is a blue giant.
By the way, the three dog constellations are Canis Major, the greater dog, found one and a half fists to the lower left of Orion; Canis Minor, the lesser dog, found two and a half fists to the left of Betelgeuse; and Canes Venatici, the hunting dogs, found low in the northeast sky. Canis Major contains Sirius, the brightest star in the nighttime sky.

Sunday: On these cold mornings, it is difficult to get going. You just want to plop into a chair and sit still. But, are you really sitting still? You’re moving at about 700 miles per hour due to the rotation of the Earth on its axis and 66,000 miles per hour due to the revolution of the Earth around the Sun. If that’s not enough, the entire solar system is orbiting the center of the galaxy at a whopping 480,000 miles per hour! So while you may be sitting still with respect to your living room (and all of the over achievers in your house), you are NOT sitting still with respect to the center of the galaxy. For more information about this concept, go to http://goo.gl/lPVPS. Before you barf from all of that motion, go outside twice over the next 12 hours and observe five Solar System objects. At 6 p.m., Venus is two and a half fists held upright and at arm’s length above the southwest horizon. Mars is a fist to the upper left of Venus. At 7 a.m. tomorrow, Mercury is less than a fist above the southeast horizon and Saturn is a fist to the upper right of Mercury. Jupiter is three fists above the south-southwest horizon.

Monday: Vega is one fist above the northwest horizon at 7 p.m.

Tuesday: Have you ever planned a vacation to a place because it was supposedly the up-and-coming locale? Then, when the vacation time finally arrives, you find out the place doesn’t live up to its billing? A little over four years ago, astronomers discovered that the star Tau Ceti, one of our closest neighbors at 12 light years away, has five planets. They claimed two of the planets are in the so-called habitable zone where the temperature is just right for having liquid water. Time for a va-ca-tion! Well, not so fast. A new model indicates that one of the planets is in the habitable zone only is you make very generous assumptions. And the other probably moved into the habitable zone fairly recently. In any case, you’ll want to do some research before you travel there. Tau Ceti is two and a half fists above the south-southwest horizon at 7 p.m. For more information about the discovery, go to http://goo.gl/mVdncK.

Wednesday: You never see a giraffe on the ground in Ellensburg. But you can look for one every night in the sky. The constellation Camelopardalis the giraffe is circumpolar from Ellensburg’s latitude of 47 degrees north meaning it is always above the horizon. Don’t expect to be overwhelmed by the appearance of the stars in Camelopardalis. The brightest star in the constellation appears only about half as bright as the dimmest star in the Big Dipper. However, the actual luminosities of the three brightest stars in Camelopardalis are very high, each at least 3,000 times more luminous than the Sun. Alpha Camelopardalis, a mind boggling 600,000 times more luminous than the Sun, is seven fists above the northern horizon at 9 p.m.

Thursday: Do you see a hunter when you look at Orion? Betelgeuse and the bright star one fist to the right of it are the broad shoulders of the hunter. Rigel and Saiph, the bright star to the left of Rigel, represent the knees.  The Maya saw the equilateral triangle formed by Rigel, Saiph, and the left-most belt star as the “Three Stones of the Hearth”. The Orion Nebula is in the center of the hearth and it represents the flame, called K’ak.

Friday: Listen; do you want to know a secret? Do you promise not to tell? Whoa oh, oh. The Beatles certainly didn’t write this song about the Barringer meteorite crater in Arizona. Astronomers are studying this 50,000-year-old impact to learn more about our planet’s violent history as well as the physics of impacts throughout the solar system. If you’d like to be let in on some of these secrets, go to http://goo.gl/sqbBe.

The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to https://nightsky.jpl.nasa.gov/planner.cfm.

Wednesday, January 4, 2017

The Ellensburg WA sky for the week of 1/7/17


Saturday: How do you study the life cycle of a dog? Easy. Get a dog from the animal shelter, care for it for 15 years and study it. How do you study the life cycle of a star? Easy. Pick a star, watch it for a few billion years, and…. Wait a minute. Astronomers can’t observe something for a few billion years. Instead, they study stars that are at different points in their long life cycle and piece together the information from those different stars. What they do is like studying a one-year-old dog for a few minutes, then studying a different two-year-old dog for a few minutes, and so on. The sky in and near the constellation Orion provides an example of four objects at different points of star life.
First, find Rigel, the bright star in the lower right corner of the constellation Orion. This star, rapidly burning its fuel for a high energy but short-lived existence, is three and a half fists held upright and at arm’s length above due south at 10 p.m. It was not, is not, and never will be like our Sun. However, about one fist up and to the left are the three objects of Orion’s sword holder. The middle “star” is really a star-forming region called the Orion nebula. There you’ll find baby Suns. Now, look about two fists to the right and one fist down from Rigel. You should be looking at a star that is about one tenth as bright as Rigel but still the brightest in its local region. The third star to the right of that star is Epsilon Eridani, the most Sun-like close and bright star. Betelgeuse, in the upper left corner of Orion, is a star at the end of its life that started out life a bit larger than the Sun.

Sunday: A new year leads us to contemplate our future. Let’s take some time to contemplate the Sun’s future. The Sun has spent a few billion years as a stable star fusing hydrogen into helium. Once that easily fusible hydrogen is gone, the Sun’s outer layer will puff up like a hot air balloon, getting larger, cooler, and redder. The star Aldebaran, in the constellation Taurus looks like what our Sun will look like in a few billion years. Read more about Aldebaran and the Sun’s future at https://stardate.org/radio/program/moon-and-aldebaran-25. At 9:30 p.m., Aldebaran is almost exactly 60 degrees, or six fists, above due south, about a half a fist to the left of the Moon.

Monday: At 6 p.m., Venus is a little more than two fists above the southwest horizon. Mars is a little more than a fist to the upper left of Mars. The dimmest planet, Neptune, is between the two. Grab a pair of binoculars and orient Venus in the lower right portion of the field of view. Neptune will be in the upper left portion of your field of view.

Tuesday: January is the coldest month of the year so it is time to turn up the furnace. Fornax the furnace is one fist above due south at 7 p.m.

Wednesday: Tonight’s late night full moon is in the constellation Gemini. Tonight’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/O801zk.

Thursday: At 6:45 am, Saturn is a little less than one fist above the southeast horizon. Mercury is about one fist to the lower left of Saturn. Jupiter is three and a half fists above the south horizon.

Friday: Have you ever looked down on the ground and spotted a penny? In Yakima? While you were standing in Ellensburg? If you have, then you may be able to see the star Hamal as more than just a point of light. It has an angular diameter that can be directly measured from Earth. Hamal, the brightest star in the constellation Aries the ram, has the same angular diameter as a penny 37 miles away. (For comparison, the moon is about half the diameter of a penny held at arm’s length.) Hamal is three and a half fists above due west at 11 p.m.

The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to http://nightsky.jpl.nasa.gov/planner.cfm.

Wednesday, December 28, 2016

The Ellensburg WA sky for the week of 12/31/16


Saturday: Neptune is the dimmest planet that can be seen with binoculars. That makes it difficult to find. But not tonight. It is right next to Mars in the evening sky. First find Mars, the bright, reddish planet nearly three fists held upright and at arm’s length above the south-southwest horizon at 5:30 p.m. Now, center Mars in your binoculars. Neptune is the dot just to the upper left of Mars. View Mars again once an hour until it gets to close to the horizon at about 9 p.m. You’ll notice Neptune moving towards Mars in the sky. Actually, Mars, being much closer to Earth, is moving toward Neptune in the sky. Don’t forget to look at Venus, the bright point of light two fists above the southwest horizon.

Sunday: Today is the day we celebrate the anniversary of something new – a new classification of celestial objects. Giuseppe Piazzi discovered Ceres [pronounced sear’-ease], the first of what are now called “asteroids”, on January 1, 1801. Ceres is the largest asteroid in the belt between Mars and Jupiter. At first, Piazzi thought it was a star that didn’t show up on his charts. But, he noted its position changed with respect to the background stars from night to night. This indicated to him that it had to be orbiting the Sun. The International Astronomical Union promoted Ceres to the status of “dwarf planet” in August of 2006.
It turns out that this is a good time to view Ceres with binoculars. Ceres is four and a half fists above due south at 7 p.m. First find Alrischa, the third brightest star in Pisces. It is a little east of due south at 7 p.m. Move your binoculars so this star is on the far left of your binocular field of view. Ceres should be on the far right of your field of view. It will look like a star. However, if you go to this region of the sky over multiple nights, you’ll notice that one “star” changes position from night to night. This is Ceres.

Monday: Late tonight and early morning’s weather forecast: showers. Meteor showers, that is. The Quadrantid meteor shower peaks late tonight and early tomorrow morning between midnight and dawn. Meteor showers are named after the constellation from which the meteors appear to originate. That makes this shower mysterious because there isn’t any constellation with this name now. The shower was named after Quadrans Muralis, an obsolete constellation found in some early 19th century star atlases. These meteors appear to come from a point in the modern constellation Draco the dragon. This point is about three fists held upright and at arm’s length above the northeast horizon at 1 a.m. This year, the waxing crescent moon will set long before the best viewing time and will not obscure the dimmer meteors. Meteors are tiny rocks that hit the Earth and burn up in the atmosphere. Most meteors are associated with the path of a comet. This shower consists of the debris from an asteroid discovered in 2003. Keeping with the comet-origin paradigm, astronomers think the asteroid is actually an “extinct” comet, a comet that lost all of its ice as it passed by the Sun during its many orbits. For more information about the Quadrantid meteor shower, go to http://earthsky.org/?p=4287.

Tuesday: You’ve seen the term “a pinch to grow an inch.” Well, Jupiter’s extremely strong gravitational field “pinches” Jupiter so much that it causes Jupiter to shrink by about an inch a year. Look for the svelte Jupiter three and a half fists above the south horizon at 7 a.m.

Wednesday: If the Sun looks big today, your eyes are not playing tricks on you. The Earth is at perihelion at about 6 a.m., Pacific Standard Time. If you dig out your Greek language textbook, you’ll see that peri- means “in close proximity” and helios means “Sun”. So, perihelion is when an object is closest to the Sun in its orbit, about 1.5 million miles closer than its average distance of 93 million miles. Since it is winter in the Northern Hemisphere now, the seasonal temperature changes must not be caused by the Earth getting farther from and closer to the Sun. Otherwise, we’d have summer when the Earth is closest to the Sun. The seasons are caused by the angle of the sunlight hitting the Earth. In the winter, sunlight hits the Earth at a very low angle, an angle far from perpendicular or straight up and down. This means that a given “bundle” of sunlight is spread out over a large area and does not warm the surface as much as the same bundle in the summer. For the Northern Hemisphere, that very low angle occurs in December, January and February.

Thursday: Has it been tough to wake up this past week? It should have been because the sunrise has been getting a little later since summer started. I know. I know. December 21 was the shortest day of the year. But, because the Earth’s orbit around the Sun is elliptical and not circular, the Earth does not travel at a constant speed. It moves faster when it is closer to the Sun and slower when it is farther away. This leads to the latest sunrise occurring in early January and the earliest sunset occurring in early December, not on the first day of winter, the shortest day of the year. On the first day of winter, however, the interval between sunrise and sunset is the shortest. For more information, go to http://goo.gl/SJC5r.

Friday: Saturn is about  a half a fist above due southeast at 7 a.m. Mercury is less than a fist to the lower left of Saturn, a half a fist above the southeast horizon.

The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to http://nightsky.jpl.nasa.gov/planner.cfm.

Friday, December 23, 2016

The Ellensburg WA sky for the week of 12/24/16


Saturday: I know you’re staying up late to train yourself to wait up for Santa. So look out a south-facing window at 12:30 a.m. and see Sirius, the brightest star in the nighttime sky, as high as it ever gets in the sky. It is two and a half fists held upright and at arm’s length above due south.

Sunday: Where is the one who has been born King of the Jews? We saw Jupiter being eclipsed by the Moon in the east and have come to worship him” (Matthew 2:2, Bruce Palmquist version, informed by Michael Molnar). There are many theories as to the physical explanation of the Star of Bethlehem, the celestial object that guided the wise men to the location of Jesus. Some people think it was a recurring nova, a star that explodes. Some think it was a close alignment of bright planets. Some think it was a miracle that requires no physical explanation. In 1991, astronomer Michael Molnar bought an ancient Roman Empire coin that depicted a ram looking back at a star. Aries the ram was a symbol for Judea, the birthplace of Jesus. The Magi, or “wise men”, who visited the baby Jesus practiced astrology and would have been looking in that region of the sky for the king prophesied in the Old Testament. Molnar, a modern day wise person, used sky simulation software to model the positions of planets and the Moon in the region of Aries. According to his model, Jupiter was eclipsed, or blocked, by the Moon on the morning of April 17, 6 BC. A book written by the astrologer of Constantine the Great in 334 AD supports Molnar’s theory. The book describes an eclipse of Jupiter in Aries and notes a man of divine nature born during this time. See https://goo.gl/SwkLcL for more information.
The moon, Aries, and Jupiter make an appearance in the Christmas sky. At 6 a.m., Jupiter is three and a half fists above due south and the moon is two fists above the southeast horizon. At 8 p.m., the dim constellation Aries is six and a half fists above due south.

Monday: Is your favorite someone lamenting that she didn’t get that space-related calendar that she wanted? Are you sad that you ran out of money and can’t fulfill her last-minute wish? Worry not. The Jet Propulsion Laboratory has a free calendar summarizing much of the work that it has done. Download the calendar at https://goo.gl/ua3IUf.

Tuesday: Venus is prominent in the southwest sky, right after sunset. It is about two fists above the southwest horizon at 5 p.m. Mars is a fist and a half to the upper left of Venus.

Wednesday: You’ve heard the term “a pinch to grow an inch.” Come on. Now I know you have. While there is no pinching involved, the distance between the Earth and moon increases by about an inch a year. Does it look farther tonight than when you looked at it on Sunday? It’s 3/365ths of an inch farther from the Earth.

Thursday: This week’s article has pointed out some planets visible to the naked eye and enhanced with binoculars. It turns out that this is a good time to view the largest asteroid, Ceres, with binoculars. Ceres, also classified as a dwarf planet, is four and a half fists above due south at 7 p.m. First find Alrischa, the third brightest star in Pisces. It is a little east of due south at 7 p.m. Move your binoculars so this star is on the far left of your binocular field of view. Ceres should be on the far right of your field of view. It will look like a star. However, if you go to this region of the sky over multiple nights, you’ll notice that one “star” changes position from night to night. This is Ceres. Read more about everyone’s second favorite dwarf planet at https://goo.gl/9Pmxkf.

Friday: Did you get a new telescope for Christmas? Skyandtelescope.com has a good article on how to get started using it. Go to https://goo.gl/c8fol5. Any observing tip about the night sky should include Saturn. Saturn is a half a fist above the southeast horizon at 7 a.m. Even this close to the horizon and the rising Sun, a small telescope (or even a good pair of binoculars) will reveal the rings and its largest moon, Titan. NASA’s Cassini mission has revealed Titan as a world with methane lakes, hydrocarbon-rich dunes, and a large sub-surface ocean. Read more at https://saturn.jpl.nasa.gov/science/titan/.

The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to http://nightsky.jpl.nasa.gov/planner.cfm.

Thursday, December 8, 2016

The Ellensburg WA sky for the week of 12/17/16

Saturday: Today is Saturnalia, an ancient Roman festival in honor of their god Saturn, the god of agriculture and time. The holiday featured a break from work and school, a public banquet, and private gift giving. Some of these customs influenced the secular aspects of Christmas celebrations. After Sheldon hugged Penny on The Big Bang Theory, Leonard said, “It’s a Saturnalia miracle.” It would be nearly a miracle if you saw the planet Saturn today. It rose just a few minutes before the Sun. It won’t be easily visible in the morning sky until the end of December.

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

Monday: “Lately, I’ve been, I’ve been losing sleep. Dreaming about the things that we could be. But baby, I’ve been, I’ve been praying hard, said no more counting dollars. We’ll be counting 9,096 stars, yeah we’ll be counting 9,096 stars.” Luckily, artistic judgment prevailed over scientific precision in the OneRepublic hit “Counting Stars”. According to the Yale Bright Star Catalog, there are 9,096 stars visible to the naked eye across the entire sky if you are observing from a very dark site. In the northern United States, where a part of the sky is never visible, that number drops to about 6,500. In the middle of a small city at mid-latitudes, like Ellensburg, that number drops to a few hundred. No wonder someone has been losing sleep. Learn more about the star count at http://goo.gl/nt8d80.

Tuesday: Do you look into a nursery and say, “it’s a boy” or “it’s a girl”? Not me. I say, “It’s a star”. Of course, I like looking into a stellar nursery – a star-forming region such as the Orion Nebula in the middle of Orion’s sword holder. The Orion Nebula looks like a fuzzy patch to the naked eye. Binoculars reveal a nebula, or region of gas and dust, that is 30 light years across. The center of the nebula contains four hot “baby” stars called the Trapezium. These hot stars emit the ultraviolet radiation that causes the Nebula’s gas to glow. The Orion Nebula is two and a half fists above the southeast horizon at 9 p.m.

Wednesday: At 2:44 a.m., the Sun reaches its lowest point in the sky with respect to the background stars. This point is called the Winter Solstice. During the day that the Sun reaches this point, your noontime shadow is longer than any other day of the year. Also, the Sun spends less time in the sky on the day of the Winter Solstice than any other day making this the shortest day of the year. Even though it is the shortest day of the year, it is not the day with the latest sunrise or the earliest sunset. The latest sunrise is during the first week in January and the earliest sunset is during the second week in December. The Sun is at its southernmost point with respect to the background stars on the day of the winter solstice. This means the Sun spends the least amount of time above the horizon on that day. But, the Sun rise and set time depends on more than its apparent vertical motion. It also depends on where the Sun is on the analemma, that skinny figure-8 you see on globes and world maps. During the second week in December, the Sun is not quite to the bottom of the analemma.  But, it is on the first part of the analemma to go below the horizon. During the first week in January, it is on the last part of the analemma to rise above the horizon. For more information on this, go to http://goo.gl/KpbkTf.

Thursday: Jupiter is less than a half a fist below the Moon at 6 a.m.

Friday: At 5:30 p.m., Venus is nearly two fists above the southwest horizon and Mars is nearly three fists above the south-southwest horizon.


The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to http://nightsky.jpl.nasa.gov/planner.cfm.

The Ellensburg WA Sky for the week of 12/10/16

Saturday: Warrant, the American glam metal band (as labeled by Wikipedia) was singing about carbon stars in its 1991 hit “I Saw Red”. The lyrics for the astronomy version are “Then I saw red, when I looked up in the sky, I saw red, Orion’s bright star it was by.” R Leporis, also known as Hind’s Crimson Star, is one of the reddest stars in the sky. It is a star near the end of its life that has burned its helium nuclei into carbon. Convective currents, like those in a pot of boiling water, bring this carbon to the surface. There it forms a layer of soot that scatters away the light from the blue end of the visible spectrum leaving the light from the red end of the spectrum to reach our eyes. For more information about Hind’s Crimson Star and a list of other deep red stars, go to http://goo.gl/EnhRe4. Hind’s Crimson star is one fist to the lower right of Rigel, the brightest star in Orion. You’ll need binoculars or a small telescope to see it Hind’s Crimson star. But you can easily spot Rigel two fists held upright and at arm’s length above the southeast horizon at 9 p.m.

Sunday: Mercury is less than a half a fist above the southwest horizon just before 5 p.m. Over the next few weeks, it will be moving closer and closer to the Sun in the sky. By early January, it will be visible in the morning sky. Venus and Mars don’t appear to move through the sky nearly as fast as Mercury. Start measuring for yourself tonight. At 5 p.m., Venis is about a fist and a half above the south-southeast horizon and Mars is nearly three fists above the south horizon.

Monday: Two of the best, and certainly the most available, “tools” for viewing the night sky are your eyes. Your eyes let you see the entire sky in just a few seconds. Your eyes can read star charts, decipher astronomy apps, and spot meteors while your friend is still setting up her tripod. Your naked eyes are not as effective as gathering light. They work well when the light source is comparatively bright and the detailed features are fairly large. It’s best to practice on a special Solar System body known scientifically as the Magnificent Optical Object of Nearness. Artists such as Jan van Eyck and Leonardo da Vinci produced the first realistic naked eye depictions of the Magnificent Optical Object of Nearness. This week you can use your own eyes to observe evidence of violent collisions and ancient lava flows. For more information to observe the Magnificent Optical Object of Nearness, better known as the Moon, go to http://goo.gl/JLhraO.

Tuesday: The Geminid meteor shower peaks for the next two nights. Meteor showers are named after the constellation from which the meteors appear to originate. These meteors appear to come from a point in Gemini the twins. This point is about three fists above the east-northeast horizon at 9 p.m. tonight. You can follow this point throughout the night, as it will remain near the bright star Castor, the right hand star of the “twin” stars Pollux and Castor. This shower is typically one of the best ones of the year producing bright, medium speed meteors with up to 80 meteors per hour near the peak. This year, the nearly full moon will obscure some of the dimmer meteors.
Most meteor showers occur when the Earth passes through the orbital trail of a comet. The broken off comet fragments collide with the Earth and burn up in the atmosphere. Astronomers had searched for a comet source for this shower since 1862 when the shower was first observed. Finally, in 1983, astronomers discovered the object that created the fragments that cause the meteor shower. To their surprise, it was a dark, rock that looked like an asteroid, not a shiny icy comet. Astronomers named this object Asteroid 3200 Phaethon. But, they still don’t know if it an asteroid or if it is a comet with all of its ice sublimated away by many close passes by the Sun. For more information about the Geminid shower, go to http://earthsky.org/space/everything-you-need-to-know-geminid-meteor-shower. Now that’s a self-explanatory URL!

Wednesday: Columbia the dove, representing the bird Noah sent out to look for dry land as the floodwaters receded, is perched just above the ridge south of Ellensburg. Its brightest star Phact is about one fist above the south horizon at midnight.

Thursday: Jupiter is three fists above the south horizon at 7 a.m.

Friday: Just before Christmas, you look for junk to clean out of your closets so you can re-gift it. I mean, so you can throw it out or recycle it. NASA’s Meter Class Autonomous Telescope on Ascension Island is a key tool in a program tracking about 22,000 pieces space junk. Some of this junk is dangerous. The International Space Station occasionally performs debris avoidance maneuvers to keep is panels and sensitive instrument safe. For more information about the project, go to http://goo.gl/Kxgihd.

The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to http://nightsky.jpl.nasa.gov/planner.cfm.

Wednesday, November 30, 2016

The Ellensburg WA sky for the week of 12/3/16


Saturday: Venus is a fist held out at arm’s length below the Moon, in the south-southwest sky at 4:45 p.m. Mercury is the more challenging object to find, less than a half a fist above due southwest at this time.

Sunday: Mars is less than a half a fist to the left of the Moon at 9 p.m. They are both just above the west-southwest horizon.

Monday: The earliest sunset of the year occurs throughout the next week: 4:13 p.m. This seems odd because the shortest day of the year, the winter solstice, isn’t for about two more weeks. The Sun is at its southernmost point with respect to the background stars on the day of the winter solstice. This means the Sun spends the least amount of time above the horizon on that day. But, the sunrise and sunset times depend on more than its apparent southward motion in the sky. It also depends on where the Sun is on the analemma, that skinny figure-8 you see on globes and world maps. During the second week in December, the Sun is not quite to the bottom of the analemma. But, it is on the leading edge of the analemma, the first section to go below the horizon. For a slightly different explanation about this, go to http://goo.gl/kjnHP. Or just go watch the sunset. But don’t stare at the Sun.

Tuesday: Most constellations don’t look like the object their name refers to. That’s because most constellations don’t have such a simple to object to emulate as Triangulum does. Triangulum is shaped like a… wait for it…. Wait for it…. A thin isosceles triangle. Metallah is the only named star in the constellation. In Latin this star is called Caput Trianguli, the head of the triangle. Triangulum is seven fists above due south horizon at 9 p.m. It is pointing down and to the right with Metallah being the southernmost star at this time of night. The Triangulum Galaxy can be seen with binoculars about a half a fist to the right of Metallah.

Wednesday: Jupiter is three and a half fists above the south-southeast horizon at 7 a.m.

Thursday: It’s getting too cold to see frogs in the wild. Some rich politicians see them on their dinner plate. But this is a great time to see frogs in the sky. Ancient Arabs referred to the stars that we now call Fomalhaut and Diphda as Ad-difdi al-awwal and Ad-difda at-tani. This means the first frog and the second frog, respectively. Both frogs are low in the southern sky at 7 p.m. Fomalhaut is one fist above the horizon and one fist to the east of due south. The slightly dimmer Diphda a little more than two fists above the horizon and one fist to the west of due south.

Friday: Cosmic rays are high-energy subatomic particles. When they strike the Earth, they interact with the atmosphere, creating a cascade of other particles including muons. These muons pass through almost everything. So muons (HUH), what are they good for? Absolutely nothing? Wrong. They are good for probing the interior of places too fragile or too dangerous to enter. Scientists observed the pattern of muons passing through the Fukushima nuclear reactor to determine the location and orientation of the damaged fuel rods. For more muon application, go to https://stardate.org/radio/program/cosmic-rays-iii.

The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to http://nightsky.jpl.nasa.gov/planner.cfm.