Thursday, January 16, 2025

The Ellensburg, WA sky for the week of January 18, 2025

Saturday: Saturn is just to the lower left of the very bright Venus, two and a half fists held upright and at arm’s length above due southwest at 6:00 p.m. And this is just the start of Solar System neighborliness, also called a planetary alignment. Neptune is about a fist to the upper left of Venus. Neptune is difficult to find, even with binoculars. Also visible with binoculars is Uranus. However, it is easier to find than Neptune for two reasons. First, it is about seven times brighter. Second, it is close to an easy-to-find object. First find the bright open star cluster called the Pleiades, a tiny cup-looking object nearly six fists above the southeastern horizon. With the Pleiades on the far left of your binocular field of view, there will be a little arch of four stars of similar brightness near or just outside the right of your field of view. Under this arch is a point of light that is a little dimmer. This point of light and the arch make an ice cream cone shape. The point of light at the bottom is Uranus. You’ll know you’ve found the correct point of light if it moves a tiny bit compared to the neighboring stars over the next few weeks. The next planet is easy to see - Jupiter - nearly six fists above due southeast. Finally, Mars is nearly three and a half fists above due east.

Sunday: Winter is the best season for finding bright stars. And if you only want to set aside a few minutes, 10:00 p.m. tonight is a great time because the winter hexagon is due south. Starting at the bottom, find Sirius, the brightest star in the night sky, two and a half fists above the southern horizon. Going clockwise, Procyon (8th brightest star in the night sky) is about two and a half fists to the upper left of Sirius. Pollux (17th brightest) is about two and a half fists above Procyon (and right above the planet Mars). Capella (6th brightest) is about two and a half fists to the upper right of Procyon and close to straight overhead. Going back to Sirius at the bottom, Rigel (7th brightest) is about two and a half fists to the upper right of Sirius. Aldebaran (14th brightest) is about three fists above Rigel (and right below the planet Jupiter). Adhara (22nd brightest) is a little more than a fist below Sirius and Castor (24th brightest) is right above Pollux. Betelgeuse (10th brightest) is in the center of the hexagon, five fists above due south. That’s nine of the 24 brightest stars visible in the night sky congregated in one small section of the sky.

Monday: Spica is less than a fist to the right of the moon in the southwestern sky at 7:00 a.m. Tomorrow at this time, it will be a half a fist to the right of the moon, providing a great way to determine how much the moon appears to move in the sky over one day.

Tuesday: This week is, on average, the coldest of the year so it is time to turn up the furnace. Fornax the furnace is one fist above due south at 7:00 p.m.

Wednesday: Wintertime weather in the northern USA can be crazy cold. Astronomers have recently discovered some brown dwarf stars have crazy hot weather. Brown dwarfs and small stars that are not massive enough to fuse hydrogen atoms and fuse hydrogen. But they are active enough to have a toxic chemical atmosphere that is as hot as a candle flame with clouds of hast moving silicate particles. Thanks to the James Webb Space Telescope, astronomers have the most detailed “weather map” of brown dwarfs ever. Read more about them at https://www.reuters.com/science/webb-telescope-reveals-wild-weather-cosmic-brown-dwarfs-2024-07-15/

Thursday: Do you ever take photos to spy on your neighbors? The Hubble Space Telescope does. In 2019, Hubble scientists released the best 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/. At 8:00 p.m., the Triangulum Galaxy is six and a half fists above the southwestern horizon. It is barely visible with binoculars. First find the Great Square of Pegasus, centered four fists above the western horizon. It is tripped so it appears to be balanced on a corner. Go to the top star in the tilted square, called Alpheratz. Move your binoculars about one binocular field of view, about a half a fist above the corner star. You’ll see a pair of stars of similar brightness in that field of view. Then move your binoculars up another field of view to two stars that are a little brighter and a little farther apart than the previous pair. The brighter of the two is named Mirach. About one binocular field of view, or about a half a fist to the right of Mirach is the largest galaxy in our neighborhood and the brightest in the sky: the Andromeda Galaxy. About one binocular field of view, or about a half a fist to the left of Mirach is the Triangulum Galaxy, also known as Messier 33 (M 33). The Triangulum is much more challenging to see with binoculars, which makes the Hubble image even more impressive.

Friday: Draco Malfoy makes an appearance in all seven books of the Harry Potter series. Perhaps you’ve heard of these. But the constellation Draco the dragon makes an appearance in the sky every night. It is a circumpolar constellation as viewed from Ellensburg meaning it never goes below the horizon. The head of the dragon is one fist above due north at 9:30 p.m. Eltanin, the brightest star in the constellation, is at the lower left-hand corner of the trapezoid-shaped head of Draco.

The positional information in this column about stars and planets is typically correct for the entire week. For up-to-date information about the night sky, go to https://nightsky.jpl.nasa.gov/planner.cfm. All times are Pacific Time unless noted.

Thursday, January 9, 2025

The Ellensburg, WA sky for the week of January 11, 2025

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 10:00 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 larger than the Sun.

Sunday: Tonight Mars is as close to Earth as it will be this orbital cycle. Find it in the southeastern sky at 10:00 p.m., about one fist to the lower left of the full moon. Jupiter is to the right of the moon, six fists above the south-southwestern horizon.

Monday: The very bright planet Venus is one and a half fists above the west-southwestern horizon at 7:00 p.m. Saturn is a half a fist to the upper left of Venus. Over the next few days, Venus will move up towards Saturn in the night sky.

Tuesday: Most constellations don’t look like the object their name refers to. That’s because most constellations don’t have such a simple 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 four and a half fists above due west at 10:00 p.m. The triangle is pointing straight down with Metallah. The Triangulum Galaxy can be seen with binoculars about half a fist to the lower right of Metallah. This is the galaxy that the USS Enterprise travels to after the warp drive engine malfunctions in The Next Generation episode called “Where No One Has Gone Before”.

Wednesday: 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 fists above due west at 11:00 p.m. Hamal is just to the left of Triangulum and is the brightest star in that region of the sky.

Thursday: Mercury is just above the southeastern horizon at 7:15 a.m.

Friday: 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 due north at 9:00 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. All times are Pacific Time unless noted.

Thursday, January 2, 2025

The Ellensburg, WA sky for the week of January 4, 2025

Saturday: If the Sun looks big today, your eyes are not playing tricks on you. The Earth is at perihelion at 7:30 this morning. 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.

Sunday: 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 late December/early January and the earliest sunset occurring in early December. Neither of these happen on the first day of winter. On the first day of winter, however, the interval between sunrise and sunset is the shortest, making it the shortest day of the year. For more information, go to http://goo.gl/SJC5r.

Monday: At 8:30 p.m., Jupiter is six fists above due southeast and Mars is three fists above due east.

Tuesday: Let’s review three important sets of three cats. There’s Josie, Valerie, and Melody of Josie and the Pussycats. Felix, Tom, and Sylvester from old time cartoons. And, if you want to get away from the mind-numbing effects of television, there’s Leo the lion, Leo Minor, and Lynx in the night sky. Leo is by far the most prominent of these three constellations. Its brightest star called Regulus is two fists above the eastern horizon at 10:00 p.m. The backwards question mark-shaped head of Leo is above Regulus and the trapezoid-shaped body is to the left of it. Leo Minor consists of a few dim stars right above Leo. Pretty wimpy. The long dim constellation called Lynx spans from just above Leo Minor to close to straight overhead. You and fellow stargazers won’t need to wear a long tail or ears to enjoy these stellar cats.

Wednesday: In 1984, American singer Rockwell released the song “Somebody’s Watching Me”, backed up by Michael Jackson. In 2020, NASA’s Spitzer Space Telescope released a picture of two bubbles of gas and dust that look like eyes watching you. Stare back at them by going to https://www.spitzer.caltech.edu/image/ssc2020-17a-something-out-there-is-watching-you.

Thursday: Tonight, Venus is as far away from the Sun in the sky as it will get this orbital cycle. Since Venus is in the evening sky, it is east of the Sun so this occurrence is called the greatest eastern elongation. This evening will be the best evening to observe Venus for the next few weeks. Venus is two fists above the southwestern horizon at 6:30 p.m. Saturn is a fist to the upper left of Venus tonight. By mid-April, Venus will be visible in the morning sky.

Thursday, December 26, 2024

The Ellensburg, WA sky for the week of December 28, 2024

Saturday: Red is a popular Christmas color. It is also a popular star color. And 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 Hind's Crimson star. But you can easily spot Rigel two and a half fists held upright and at arm’s length above due southeast at 8:00 p.m.

Sunday: Mercury is a half a fist above the southeastern horizon at 7:00 a.m.

Monday: Venus is two fists above the southwestern horizon and Saturn is three fists above the south-southwestern horizon at 6:00 p.m.

Tuesday: Jupiter is six fists above due southeast and Mars is three fists above due east at 9:00 p.m.

Wednesday: 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.

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 northeastern horizon at 1:00 a.m. This year, the Moon sets early in the evening so even the dimmer meteors will be visible.

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 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.

Friday: Now that you know meteors are rocks that burn up in the atmosphere, you will soon start to wonder what would happen if those rocks hit the surface of the Earth. Well, wonder no more. The browser-based app called Asteroid Launcher will simulate the collisions. You select the asteroid type, size, speed, and angle of impact. The most common impactor material is stone, and the typical speed is 40,000 miles per hour, in case you want to introduce some realism into your simulation. Go to https://neal.fun/asteroid-launcher/, click on the map where you want the asteroid to land and then launch your virtual asteroid.

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. All times are Pacific Time unless noted.

Thursday, December 19, 2024

The Ellensburg, WA sky for the week of December 21, 2024

Saturday: At 1:20 a.m., Pacific Standard Time, 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 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. However, the Sun's rise and set times depend 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 meaning that’s when we have the latest sunrises.

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 of space junk. Some of this junk is dangerous. The International Space Station occasionally performs debris avoidance maneuvers to keep its panels and sensitive instruments safe. For more information about the project, go to http://goo.gl/Kxgihd.

Monday: Venus is one and a half fists above the southwestern horizon and Saturn is three fists above the south-southwestern horizon at 6:00 p.m.

Tuesday: Mercury is one fist above the southeastern horizon at 7:00 a.m.

Wednesday: 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.

Libra and Jupiter are visible in the early evening sky tonight. Aries is five fists above due southeast at 6:00 p.m. Jupiter is three fists above due east. The moon isn’t visible until tomorrow morning, one and a half fists above the southeastern horizon at 6:00 a.m.

Thursday: Did you get a telescope or binoculars 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 into an area of interest and learn about objects that are visible through your telescope. I like SkySafari, a free app or low-cost iPhones app (depending on their promotions at the time). But there are many other good ones to choose from for little or no money. Go to https://www.lifewire.com/best-stargazing-apps-5086553 for seven short reviews. One of your first targets should be the Pleiades open star cluster. It is bright, easy to see with the naked eye and even more interesting in binoculars. It is six fists above due southeast at 8:00 p.m.

Friday: Aside from the Big Dipper, the northern sky doesn’t get enough love. Vega, the bright star in the constellation Lyra, is one fist above due northwest at 8:00 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. All times are Pacific Time unless noted.

Thursday, December 12, 2024

The Ellensburg, WA sky for the week of December 14, 2024

Saturday: Jupiter is less than a fist held out at arm’s length to the right of the nearly full moon in the eastern sky at 7:00 p.m. They will stay in this same orientation throughout the evening and into the late-night sky.

Sunday: Are you disappointed because you are not going anywhere for the holidays? Why not take a (virtual) trip to outer space using Google’s new visualization tool called 100,000 Stars. It shows the stars in our neighborhood in an accurate 3-D simulation. The Sun is initially at the center. If you zoom in, you can click on neighboring stars and learn more about them. Go to http://stars.chromeexperiments.com/ for the simulation. It works best on a Chrome browser.

Monday: One of those stars in our neighborhood, the bright star Sirius, is one and a half fists above due southeast at 10:00 p.m.

Tuesday: Today is the start of the Saturnalia celebration, 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. For example, after Sheldon hugged Penny on The Big Bang Theory, Leonard proclaimed, “It’s a Saturnalia miracle” https://youtu.be/yarNJnZw2yk. It would not be a miracle if you saw the planet Saturn today. It is three fists above the south-southwestern horizon at 6:30 p.m. The very bright planet Venus is one fist above due southwest at this time.

Wednesday: Mars is right below the moon, three fists above due east at 10:00 p.m. As the hours go by, the moon will move slightly eastward compared to Mars, making it look like Mars is moving past it in the race from east to west. This is a great night to see how the moon appears to move slightly differently across the sky compared to planets.

Thursday:  With the Sun as low as it gets in the Northern Hemisphere winter sky this weekend, you may wish it was a little more prominent. Every orbit, NASA’s Parker Solar Probe has a close encounter with the Sun. Its last close encounter was in early October. Its next close encounter will be the closest one yet, passing just 3.8 million miles from the solar surface on Christmas Eve. It will pass through the boundary between outer space and the region where the Sun’s magnetic field has a tight hold on the plasma that makes up the outer layer of the Sun. Since the Sun does not have a solid surface, this is as close to touching the Sun as an object can get. It is analogous to “touching” a cloud. The cloud does not have a definite surface but there is a boundary between “cloud” and “not cloud”. For more about the mission plus short videos, go to http://parkersolarprobe.jhuapl.edu/.

Friday: Wow. The moon gets around. Now it is by the bright star Regulus at 10:00 p.m. Regulus is just to the right of the moon, one fist above the east-northeastern horizon. Like Mars and the moon on Wednesday, tonight you can see how the moon appears to move compared to planets. Spoiler alert: stars and planets appear to move very similar to each other compared to the moon’s apparent motion. This is because the moon is so much closer to the Earth than stars and even than relative neighbor planets such as Mars.

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. All times are Pacific Time unless noted.

Thursday, December 5, 2024

The Ellensburg, WA sky for the week of December 7, 2024

Saturday: Imagine Opie and Andy Taylor walking down the dirt path at night to that fishing hole in the sky. They’d probably be looking to catch Pisces, the two fish already conveniently tied together with two ropes. The ropes are connected at the star Alrescha, Arabic for “the cord.” Alrescha is four and a half fists held upright and at arm’s length above due south at 8:30 p.m. The fish are attached to lines of stars that branch out at one o’clock and three o’clock from Alrescha. By the way, “The Fishing Hole,” The Andy Griffith Show’s theme song, was rated the 20th best TV theme song of all time by ign.com. That’s too low of a ranking in my opinion.

Sunday: Venus is a fist above the southwestern horizon and Saturn is three and a half fists above due south at 6:00 p.m.

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

Tuesday: The earliest sunset of the year in Ellensburg occurs today: 4:12 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 better explanation of this, including a diagram, go to https://go.shr.lc/2NOMOQC. Or just go watch the sunset. But don’t stare at the Sun.

Wednesday: Jupiter is nearly six fists above the southeastern horizon and Mars is a little more than two fists above the eastern horizon at 10:00 a.m.

Thursday: While the days are getting shorter, the nighttime sky is actually getting brighter due to the greater use of low energy LED bulbs. While these bulbs use much less energy than 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://www.latimes.com/environment/light-pollution-latt-123.

Friday: The Geminid meteor shower peaks tonight and tomorrow morning. 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 four fists above due east 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 4:00 a.m., 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 80 meteors per hour under ideal conditions near the peak. This year, the moon will be near full, leaving the sky too light to see 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 each year. 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.

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. All times are Pacific Time unless noted.