Thursday, December 21, 2017

The Ellensburg WA sky for the week of 12/30/17

Saturday: The sky will be giving us a late holiday present in the form of a comet. Comet Heinze (C/2017 T1) will pass closest to Earth on January 4. At its brightest, it will be visible with small telescopes and 50-mm or larger binoculars. Go to https://goo.gl/2iL224 for a finder chart.

Sunday: The next few mornings provide a great example of how the planets move with respect to each other and with respect to the background stars. Every morning at 7 a.m., look about two and a half fists held upright and at arm’s length above the south-southeast horizon. This morning, Jupiter and Mars are a little less than a half a fist from each other with the dimmer Mars to the upper right of Jupiter. As the days go by, they move closer together with Mars “passing” Jupiter next Saturday.

Monday: 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.
Tonight’s Full Moon is a supermoon, the biggest one of the year. That’s because the Moon is full at nearly the same time as it is at its closest point to Earth, called perigee. Read more about the supermoon at http://earthsky.org/?p=270121.

Tuesday: If the Sun looks big today, your eyes are not playing tricks on you. The Earth is at perihelion at about 9 p.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.

Wednesday: 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 nearly full Moon will 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=155137.

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: You’ve heard 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 two and a half fists above the south-southeast horizon at 7 a.m. The diminutive Mars snuggles within a pinky-width to the right 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.

The Ellensburg WA sky for the week of 12/23/17

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

Monday: 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 7 a.m., Jupiter is two fists above the southeast horizon. At 8 p.m., the dim constellation Aries is six and a half fists above due south and the moon is three fists above the southwest horizon.

Tuesday: 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/hFu1UB.

Wednesday: 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 Mars. Even a small telescope will enable you to see how the angular size of Mars changes drastically from when Earth and Mars are far apart, as they are now, to when they are close together, as they will be in July of 2018. In fact, in July of 2018, Mars will be closer to the Earth than any year since 2003. Mars is two and a half fists above the south-southeast horizon at 7 p.m.

Thursday: Mercury is a good small telescope target when it far enough from the Sun in the sky, as it is this morning at 7 a.m. when it is a little less than a fist above the southeast horizon.

Friday: 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 Monday? It’s 4/365ths of an inch farther from the Earth.


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.

Friday, December 8, 2017

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

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: 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 just a few minutes after the Sun. It won’t be easily visible again until it shows up in the morning sky in mid-January.

Monday: Fomalhaut, the southernmost bright star for the northern latitudes, is one and a half fists above due south at 5 p.m.

Tuesday: Jupiter is two fists held upright and at arm’s length above the southeast horizon at 7 a.m. Less than a pinky-width below it is the bright star Zubenelgenubi. Even though it is the second brightest star in Libra, its name means Southern Claw in Arabic, an artifact of the time that it was considered part of Scorpius the scorpion. Zubenelgenubi is a visual binary, consisting of a white and yellow star that are about arc minutes apart from each other in the sky. This is about the same angular diameter of a medium sized dark spot, or mare, on the Moon and can be observed with the naked eye under good sky conditions. In actuality, they are at least 5,500 astronomical units apart from each other, about 130 times the distance between the Sun and Pluto.

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: At 8:28 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.

Friday: Headline from the tabloids: Earth sends robot to Mars in order to take a selfie. In January 2014, the Mars Curiosity rover took a picture of its night sky that included the Earth and moon. Both would easily be visible to the naked eye for a human standing on Mars. Since you can’t go to Mars, go to http://goo.gl/DqprKF look at the picture. Then go outside and look two and a half fists above the south-southeast horizon to see Mars. Mars and Jupiter are moving towards each other in the morning sky.


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 12/9/17

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: Saturn will be obscured by the light of the Sun for a few weeks before peeking up in the morning sky in mid-January.

Monday: 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.

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

Wednesday: The Geminid meteor shower peaks tonight. 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 120 meteors per hour under ideal conditions near the peak. This year IS near ideal because the Moon is close to new so it will be below the horizon for most of the night.
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. As an added bonus this year, this asteroid is visible through a small telescope. If you are up for the challenge of finding 3200 Phaethon, go to http://www.skyandtelescope.com/observing/3200-phaethon/. For more information about the Geminid shower, go to http://www.skyandtelescope.com/observing/geminid-shower-2017/. Now that’s a self-explanatory URL!

Thursday: Jupiter is less than a half a fist to the lower right of the Moon in the southeastern sky at 7 a.m. Mars is a little more than a fist to the upper right of the Moon.

Friday: 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.


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.

Friday, December 1, 2017

The Ellensburg WA sky for the week of 12/2/17

Saturday: 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.

Sunday: Many Native American Tribes call Tonight’s full Moon the Cold Moon or the Long Night Moon. Makes sense. You can find it in the constellation Taurus the bull, rising in the east-northeast sky at 5 p.m.

Monday: Saturn and Mercury are less than a half a fist above the southwest horizon at 4:45. Saturn is slightly brighter and to the upper right of Mercury.

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: 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.

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: At 7 a.m., dull red Mars is nearly three fists above the south-southeast horizon, about a half a fist to the left of the slightly brighter, blue-white star Spica. Jupiter is nearly two fists above the southeast horizon. Venus is just above the east-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 https://nightsky.jpl.nasa.gov/planner.cfm.