Wednesday, January 9, 2019

The Ellensburg WA sky for the week of 1/12/19

Saturday:  Mars is less than a fist to the right of the Moon at 9 p.m. The sky is so wondrous. It makes me want to sing. 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, four and a half fists held upright and at arm’s length above the south horizon at 9:00 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, halfway between the Big Dipper and the horizon. Canis Major contains Sirius, the brightest star in the nighttime sky.

Sunday: Venus, Jupiter and the bright star Antares make make a small triangle low in the south-southeast sky at about 7 a.m. every day this week. The very bright Venus is at the top of the triangle. Jupiter is to the lower left of Venus, one fist away this morning but getting closer everyday this week. Antares is one fist below Venus this morning.

Monday: Do you ever take photos to spy on your neighbors? The Hubble Space Telescope does. Last week, Hubble scientists released the best ever image of the Triangulum Galaxy, the second closest spiral galaxy to Earth. Hubble’s Advanced Camera for Surveys weaved together 54 separate images to provide enough detail to see 10 million individual stars out of the estimated 40 billion stars in the galaxy. See the pictures at https://www.spacetelescope.org/news/heic1901/.

Tuesday: 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.

Wednesday: 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 six 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. Astronomers have only a lower limit to the planet masses so they may be too massive for complex life to form. And the Tau Ceti system has ten times as much mass in dust and rocks as our own solar system. So 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 https://goo.gl/RTn92w.

Thursday: These next two weeks are the coldest 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.

Friday: Get ready for a total lunar eclipse this Sunday night as seen from the United States. Go to http://time.unitarium.com/events/eclipse/lunar/012019/ to determine when the eclipse will be visible in your location. In the Pacific Time Zone, the eclipse will be total from about 8:40 p.m. to 9:45 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 https://nightsky.jpl.nasa.gov/planner.cfm.

Wednesday, January 2, 2019

The Ellensburg WA sky for the week of 1/5/19

Saturday:  The CWU Physics Department and the College of the Sciences is hosting its monthly First Saturday planetarium show today from noon to 1 p.m. CWU professor Bruce Palmquist will give a presentation called “The sky in different wavelengths”. If you want the chance to say, “look at the pretty colors”, come to this show. The show is free and open to all ages. There will be a show at noon on the first Saturday of every month of the school year hosted by different CWU astronomers and astronomy educators. The CWU Lydig Planetarium is room 101 in Science Phase II, just off the corner of 11th and Wildcat Way, H-11 on the campus map found at https://www.cwu.edu/facility/campus-map. 
If you are going to be in northeast Russia this afternoon, there will be a partial solar eclipse to view. For more information about this, go to the NASA solar eclipse website at https://eclipse.gsfc.nasa.gov/SEsearch/SEsearchmap.php?Ecl=20190106 

Sunday: This morning is  Venus’ greatest western elongation. So what, you say? Not so what. This means Venus is far from the Sun in the sky. So what, you say? Not so what. This means that Venus is easy to observe. It is two and a half fists held upright and at arm’s length above the south-southeast horizon at 7:15 am. It is the brightest point of light in that part of the sky. Jupiter, the second brightest point of light, is a fist and a half to the lower left of Venus and a fist and a half above the horizon. If you look carefully, you may be able to see Mercury a little bit above the southeast horizon. 

Monday: 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. 

Tuesday: A week ago today, the NASA probe called New Horizons sent back the first detailed image of Ultima Thule, a Kuiper Belt object (KBO) that formed in its current state about 4.5 billion years ago. Ultima looks like a 30-kilometer long reddish snowman spinning through space. Check out the newest images and the latest information at http://pluto.jhuapl.edu/. Astronomers will be downloading and processing the data over the next 20 months. 

Wednesday: Mars, the more well-known red Solar System object, is four and a half fists above due south at 5 p.m. 

Thursday: January 10-13 is the worldwide celebration of 100 hours of astronomy. Of course, the CWU Physics Department started early with the First Saturday planetarium show earlier in the week. The Seattle Astronomical Society will have events in the South King County area Friday and Saturday night. Go to https://www.100hoursofastronomy.org and select “Events” for more information. 

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 https://nightsky.jpl.nasa.gov/planner.cfm

Wednesday, December 26, 2018

The Ellensburg WA sky for the week of 12/29/18

Saturday: A new year, a new target for New Horizons. At 9:33 p.m., Pacific Standard Time on December 31, New Horizons, the probe that taught us so much about Pluto in 2015, will be make its closest approach to Ultima Thule. Because Ultima is so far from Earth, the signal with the first information won’t reach Earth for about ten hours. Based on images from the Hubble Space Telescope, astronomers know that Ultima will be reddish in color and be either oblong in shape or consist of two spheroids close together like a dumbbell. During the flyby, astronomers will gather information to learn more about the geology and surface composition of Ultima, as well as whether or not it has rings or moons. For more information, go to .http://pluto.jhuapl.edu/.

Sunday: Spica is one fist to the lower right of the Moon at 7 a.m. Throughout the week at 7 a.m., the Moon will be passing by three planets in the morning sky. On Tuesday, Venus will be to the lower left of the Moon. On Wednesday, Venus will be to the upper right of the Moon and Jupiter will be to the lower left. On Thursday, Jupiter will ba a half a fist to the right of the Moon. Finally, on Friday, Mercury will be squeezed between the Moon and the southeast horizon.

Monday: The bright star Regulus is two and a half fists held upright and at arm’s length above the east horizon at 11 p.m.

Tuesday: 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.

Wednesday: 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.

Thursday: 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 above the northeast horizon at 1 a.m. This year, the Moon will be below the horizon so you may be able to see up to 100 meteors per hour. 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=155137.
If the Sun looks big today, your eyes are not playing tricks on you. The Earth is at perihelion at 12:19 a.m., Pacific Standard Time today. 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.

Friday: Mars is four fists above due south at about 5 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 https://nightsky.jpl.nasa.gov/planner.cfm. 

Tuesday, December 18, 2018

The Ellensburg WA sky for the week of 12/22/18

Saturday:  I know you’re staying up late to train yourself to wait up for Santa. So look out a south-facing window at 12:44 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: 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.

Monday: The autumn star Fomalhaut is one fist above the south-southwest horizon at 6 p.m. It is getting ready for its winter nap.

Tuesday: 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/o89A4o for more information.
The moon, Aries, and Jupiter make an appearance in the Christmas sky. At 7 a.m., Jupiter is one fist above the southeast horizon and the Moon is three fists above the west horizon. At 8 p.m., the dim constellation Aries is six and a half fists above due south.

Wednesday: 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? Do you wish you could spend more quality time with her? Worry not. The Jet Propulsion Laboratory has a free moon phases calendar and calculator you can make together. Download the calendar parts at https://goo.gl/jhgWoD.

Thursday: Did you get a new telescope for Christmas? The next item on your list should be a sky watching app for your phone. These apps will help you to get familiar with the constellations and bright stars. Then you can zoom in to an area of interest and learn about objects that are visible through your telescope. I like SkySafari, a free app for iPhones. But there are many other good ones to choose from for little or no money. Go to https://goo.gl/t1DX7R for fifteen short reviews. The first object you should look at is Mars. It is bright, easy to find and out in the early evening sky so you can share the experience with children. Mars is four fists above the south horizon at 6 p.m.

Friday:“Far out, man. Astronomers just discovered the farthest out object in the Solar System and nicknamed it Farout.” This Kuiper Belt object is more than 100 times farther from the Sun than Earth is, more than twice as far as Pluto is. For more information about Farout, go to https://goo.gl/YtGsRE. Look in the early morning sky for some not so far out objects. At 7 a.m., Venus, our nearest and brightest neighbor, is about two fists above the south-southeast horizon. Mercury, the closest planet to the Sun, is about a half a fist above the southeast horizon, to the lower left of Jupiter.


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.

Thursday, December 6, 2018

The Ellensburg WA sky for the week of 12/15/18

Saturday: “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.

Sunday: Tonight, Comet 46P/Wirtanen makes the tenth closest approach to Earth of any comet since 1950. Close means somewhat bright. But “somewhat bright” doesn’t necessarily mean Comet Wirtanen will be easy to see. The light from comets are spread out and diffuse. For more information about Comet Wirtanen and how to find it, go to https://earthsky.org/space/46p-wirtanen-possibly-visible-to-eye-dec-2018. If you don’t have time to do your homework, you may be able to find it with binoculars six and a half fists above sue south and about a half a fist to the lower left of the Pleiades open star cluster.

Monday: 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.” See the miracle on YouTube. It would be nearly a miracle if you saw the planet Saturn today. It sets about an hour after the Sun. It is less than a half a fist above the southwest horizon at 4:45.

Tuesday: Mercury and Jupiter are close neighbors low in the southeast sky for the next few mornings at 7 a.m. This morning, Mercury is a little above the much brighter Jupiter. But Mercury is moving downward in the sky and Jupiter is moving upward. By December 21, you’ll be able to cover both planets with your thumb. But you won’t be able to also cover Venus. It is two and a half fists above the south-southeast horizon at this time.

Wednesday: 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.

Thursday: The brightest star in the nighttime sky is making its way into the evening sky. Sirius is one and a half a fists above the southeast horizon at 10 p.m.

Friday: At 2:25 p.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.


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.

The Ellensburg WA sky for the week of 12/8/18

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: If you had a difficult time seeing red on last night, here is an easier red target. Mars is three and a half fista above due south at 6 p.m.

Monday: 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 5:41 p.m. Fomalhaut is nearly one and a half fists above due. The slightly dimmer Diphda is two fists above the south-southeast horizon.

Tuesday: The bright star Capella is nearly straight overhead at midnight.

Wednesday: The Geminid meteor shower peaks early the next two mornings. 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 six fists above the southeast horizon at midnight 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. By 4 am, it is four fists above the southwest horizon. This shower is typically one of the best ones of the year producing bright, medium speed meteors with up to 120 meteors per hour under ideal conditions near the peak. This year IS near ideal because the Moon is near the first quarter phase so it sets before the peak time.
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. For more information about the Geminid shower, go to https://goo.gl/f4qMqg.

Thursday: 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.

Friday: This morning is  Mercury’s greatest western elongation. So what, you say? Not so what. This means Mercury is far from the Sun in the sky. So what, you say? Not so what. This means that Mercury is easy to observe. It is one fist above the southeast horizon at 7 am.  To the lower left of Mercury is Jupiter, about three times brighter but more in the glare of the Sun. To the upper right of Mercury is the much brighter Venus, two and a half fists above the 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 https://nightsky.jpl.nasa.gov/planner.cfm.

Wednesday, November 28, 2018

The Ellensburg WA sky for the week of 12/1/18

Saturday:  The CWU Physics Department and the College of the Sciences is hosting its monthly First Saturday planetarium show today from noon to 1 p.m. CWU Bruce Palmquist will give a presentation about the highlights of the winter sky. It’s more than just snow and clouds. The show is free and open to all ages. There will be a show at noon on the first Saturday of every month of the school year hosted by different CWU astronomers and astronomy educators. The CWU Lydig Planetarium is room 101 in Science Phase II, just off the corner of 11th and Wildcat Way, H-11 on the campus map found at https://www.cwu.edu/facility/campus-map.

Sunday: Venus is two and a half fists held upright and at arm’s length above the southeast horizon at 6:45 a.m. It is at its brightest point this celestial cycle, shining more than twice as bright as when it at its dimmest. The much less bright Mercury is less than a half a fist above the east-southeast horizon at this time.

Monday: The earliest sunset of the year in Ellensburg, Washington occurs throughout the 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 the Sun’s 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: Comet 46P/Wirtanen is closing in on the Earth and will make its closest approach on December 16. Currently, you need binoculars to see it but some astronomers estimate it could be visible to the naked eye under ideal conditions. It is about three fists above due south at 10 p.m. Don’t look for a sharp point of light, however. Comet 46P will look like a diffuse cloud about the same angular size as the Full Moon, or even larger. For more information and a finder chart, go to https://www.skyandtelescope.com/astronomy-news/comet-46p-wirtanen-approaches-earth/.

Wednesday: 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 mononymous 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.

Thursday: Saturn is a half a fist above the southwest horizon at 5 p.m. Mars is three fists above the south-southeast horizon. Neptune is just to the left of Mars but you’ll need binoculars to see it.

Friday: Earlier this week, we learned that the early December evenings are getting darker earlier than any time of the year. While the sky is getting darker earlier, the nighttime sky is actually getting lighter due to the greater use of low energy LED bulbs. While these bulbs use much less energy that incandescent or compact fluorescent bulbs, researchers think that people and communities are using more of the bulbs and leaving them on longer. This is increasing light pollution near cities. You can get more illumination on the subject at https://goo.gl/1CdqcH.

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