The Ellensburg WA sky for the week of 9/1/18

Today: The Ellensburg Rodeo is a “Top-25” rodeo. What does it take to be a “Top-25” star? There are many ways to rank stars. The most obvious way for a casual observer to rank stars is by apparent brightness. The apparent brightness is the brightness of a star as seen from Earth, regardless of its distance from the Earth. Shaula (pronounced Show’-la) is the 25th brightest star in the nighttime sky as seen from Earth. It represents the stinger of Scorpius the scorpion. In fact, Shaula means stinger in Arabic. Shaula has a visual brightness rating of 1.62. Sirius, the brightest star has a visual brightness rating of -1.46. (Smaller numbers mean brighter objects.) The dimmest objects that can be seen with the naked eye have a visual brightness rating of about 6. There are approximately 6,000 stars with a lower numbered visual brightness rating than 6 meaning there are 6,000 stars visible to the naked eye. Shaula is a blue sub-giant star that radiates 35,000 times more energy than the Sun. It is 700 light years away making it one of the most distant bright stars. Shaula is a challenge to find because it never gets more than a half a fist above the horizon. Look for it tonight about a half a fist held upright and at arm’s length above the south horizon, a little bit west of due south, at 8:30.

Sunday: School starts this week so it is time for a little geometry review. A square is a regular quadrilateral, which means it has four equal sides, four equal angles, and it uses the restroom on a set schedule. Go outside at 10 p.m. tonight with notebook in hand to sketch one. The Great Square of Pegasus is balancing on its corner two and a half fists above due east. The top corner of the square is two fists above the bottom corner. The other two corners are to the left and right of the line segment connecting the top and bottom corners.

Monday: Labor Day was the brainchild of labor unions and is dedicated to American workers. The first Labor Day was celebrated in 1882. The Greek mythical hero Hercules probably wished there was a Labor Day to commemorate his work. As punishment for killing his family while he was temporarily insane, he had to perform twelve nearly impossible tasks such as killing monsters or stealing things from deities. Hmmm. Maybe we shouldn’t commemorate his labors. But we can enjoy his constellation. The keystone asterism representing the body of Hercules is six fists above the west horizon at 10 p.m. For more information about the Labors of Hercules, go to http://goo.gl/ozVF5.

Tuesday: Geometry review, part 2. Go outside at 10 p.m. tonight with notebook in hand. (Good teaching involves a little repetition.) You’ll have an easy time seeing your notebook because the moon is just a little past full. A triangle is a polygon with three corners and three line segments as sides. A good example is the Summer Triangle made up of the bright stars Vega, Deneb and Altair. Vega, the brightest star in the triangle, is a little bit southwest of straight overhead. Deneb is a little bit east of straight overhead and Altair is five fists above the south horizon.

Wednesday: Venus is a half a fist above the west-southwest horizon at 8 p.m. The bright star Spica is a half a fist to the right of Venus. At this same time, Jupiter is one and a half fists above the southwest horizon

Thursday: Planets: Part 2. Let’s be bold and stay up until 9 p.m. Now, Saturn is two fists above the south-southwest horizon and Mars is one and a half fists above the south-southeast horizon.

Friday: “I’m a little teapot, short and stout. The galactic center, I pour it out.” (I’m a Little Teapot, astronomy version, 2014.) Despite its great size and importance, the center of our Milky Way galaxy and its giant black hole remains hidden to the naked eye behind thick clouds of gas and dust. By plotting the orbits of stars near the middle of the galaxy, astronomers have determined that the black hole’s mass is equal to about 4.5 million Suns. While you can’t see the actual galactic center, you can gaze in the direction of the center by looking just to the right of the teapot asterism in the constellation Sagittarius. This point is about one fist above the south-southwest horizon at 9 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. 

The Ellensburg WA sky for the week of 8/25/18

Today: Arcturus is four fists held upright and at arm’s length above the west-southwest horizon at 8:30 p.m. This star, whose name means bear watcher, is the brightest in the sky’s northern hemisphere. It follows Ursa Major, the Great Bear, around the North Star. Arcturus is the closest giant star to Earth. It is one of the few stars whose diameter can be measured directly rather than being inferred from its density and mass, which, themselves are derived from other parameters.

Sunday: This morning will be the best morning to observe Mercury for the next few weeks. Mercury is a little less than one fist above the east-northeast horizon at 5:30 a.m. Over the next few weeks, Mercury will move toward the Sun in the sky. By mid October, it will be visible in the evening sky.

Monday: Have you ever gone to a family reunion, looked around and asked, “How in the world are we related to each other?” Astronomers look around the Solar System and wonder if there is life anywhere else that we are related to. The Mars Science Laboratory landed on Mars in 2012 to investigate whether it ever had conditions favorable for life. The Venus Express studied the atmosphere of Venus from 2006 to 2014. The Cassini Mission continues to study the plume of complex organic chemicals streaming from Saturn’s moon Enceladus. NASA and the European Space Agency are planning missions to study Europa, the Jovian moon with an ice-covered ocean. And many astronomers consider the methane haze in the atmosphere in Saturn’s moon Titan similar to that of the early Earth. To learn more about the search for life in the Solar System and beyond, go to https://www.astrobio.net/, a NASA-sponsored popular science magazine. While you won’t see anyone waving back, you can see Venus, Mars, Jupiter, and Saturn in the early night sky. Start with Venus, a half a fist above the west-southwest horizon at 8:30 p.m. Then move on to Jupiter, one and a half fists above the southwest horizon.

Tuesday: Deneb is nearly straight overhead at 11 p.m. When you look at Deneb, you are seeing light that left Deneb about 1,800 years ago.

Wednesday: Are you ready for more planets? Saturn is two fists above dus south at 8:40 p.m. At this time, Mars is one fist above the east-southeast horizon.

Thursday: All stars rotate. Our Sun takes a little less than an Earth month to make one rotation. Astronomers have started to study the relationship between mass, stellar rotation, and planetary formation by aiming NASA’s Kepler space telescope toward the Pleiades open star cluster. All 1,000 stars in this group is nearly the same age, 125 million years old. Since all of the stars are the same age and formed from the same set of materials, astronomers have the ideal “laboratory” to isolate the role star mass plays on star rotation and evolution. Read more about the findings at http://goo.gl/osijIY. See the Pleiades for yourself, one fist above the east-northeast horizon at 11:30 p.m.

Friday: Yes, I know the total solar eclipse was one year ago. But one of the best photos was just released this week. It was, or more accurately, they were taken from a Southwest Airlines flight from Portland, Oregon to St. Louis, Missouri. Se and read more about the composite photograph at https://goo.gl/LUQCEP.

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 8/18/18

Saturday: “The sky is black (or light polluted), the stars are white (or red or orange or yellow or blue), the whole world gazes upon the sight (except where there are too many city lights or people are lazy.” Wow. It is difficult to write a flowing set of lyrics when there are so many parenthetical thoughts. Most people think of the sky’s blackness as a lack of stars. But dark patches in the Milky Way are actually massive clouds of dust that are blocking the stars behind them. Two of the most prominent are dark nebulae B142 and B143 in the constellation Aquila the eagle. These are easy to find and enjoy with binoculars. First find the bright white star Altair, five fists held upright and at arm’s length above the southeast horizon at 10 p.m. Then move your binoculars up a little bit to the next bright star Tarazed, about one fifth as bright. B142 and B143 are to the upper right of Tarazed. They make an “E” shape in the sky; fitting because it was American astronomer E. E. Barnard who first proposed that these were dust clouds and not simply big spaces between the stars. For more information about dark nebula, including many more to look at with binoculars, go to https://goo.gl/9tiqdh.  

Sunday: Venus is about a half a fist above the west-southwest horizon at 8:45 p.m. Jupiter is not far behind it, about one and a half fists above the southwest horizon. 

Monday: Saturn is about a thumb width to the lower left of the Moon at 11 p.m., low in the south-southwest sky. 

Tuesday: Mercury is a half a fist above the east-northeast horizon at 5:45 a.m. 

Wednesday: Mars is about a fist to the lower left of the Moon at 11 p.m., low in the southern sky. 

Thursday: Let’s all sing the galactic black hole monster song: “D is for dusty, that’s good enough for me. D is for dusty that’s good enough for me. D is for dusty that’s good enough for me. Oh dusty, dusty, dusty starts with D.” Astronomers know that spiral galaxies such as our own have super massive black holes in the center, black holes that are billions of times the mass of the Sun. They thought they got to be this massive by mergers where two galaxies collide and the gas, dust and black holes at the center of each colliding galaxy form a larger central black hole. But many distant galaxies show no signs of galactic mergers. Astronomers think the black holes at the center of these galaxies grew simply by snacking on the gas and dust that comes from supernova explosions and normal star formation. Just like the Cookie Monster gains weight by snacking on individual cookies rather than eating a cookie factory. Cookie crumbs, I mean dust, block your view of the center of our galaxy.  It is about one fist above due south at 10 p.m., between the constellations Sagittarius and Scorpius. For more information, go to http://goo.gl/L9ppJf. 

Friday: When the Moon is full, as it will be late tomorrow night, or close to full, it is difficult to see dim objects in the sky because of the sky glow. But why struggle to find dim objects when there is so much to see on the big, bright object in front of you? The lunar crater called Tycho is best seen during a full Moon. Tycho was formed about 109 million years ago when an asteroid struck the Moon, leaving a crater over 50 miles in diameter and ejected dust trails that radiate out hundreds of miles in all directions. For more lunar highlights, go to http://nightsky.jpl.nasa.gov/docs/ObserveMoon.pdf, a resource of the Night Sky Network. 

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 8/11/18

Saturday:  The Perseid meteor shower hits its peak Sunday and Monday mornings. The meteors appear to come from a point just below the W of the constellation Cassiopeia. This point is about two and a half fists held upright and at arm’s length above the northeast horizon at 11 p.m. By dawn, this point is about seven fists above the northeast horizon. If you fall asleep or forget to set your alarm, you will be able to observe this shower from about 11 p.m. to dawn for the next few nights in about the same location in the sky. The Perseid shower is one of the longest lasting showers. The Moon will be new or close to new for the next few nights. For tips about optimizing your viewing this year, go to http://earthsky.org/?p=2087. As your Mother might say, dress warm and sit in a comfortable chair for maximum enjoyment. These meteors are sand to pea-sized bits of rock that fell off of Comet Swift-Tuttle. They are traveling about 40 miles per second as they collide with the Earth and burn up in the atmosphere. 

Sunday: Mars is one and a half fists above due south at 11:45 p.m. 

Monday: Saturn is two fists above due south at 10 p.m. 

Tuesday: Need a caffeine pick-me-up? Make it a double. Need an astronomy pick-me-up? Make it a double double. Find Vega, in the constellation Lyra the lyre, nearly straight overhead at 10:00 tonight. Less than half a fist to the east (or left if you are facing south) of the bright bluish star Vega is the “star” Epsilon Lyra. If you look at Epsilon Lyra through binoculars, it looks like two stars. If you look at Epsilon Lyra through a large enough telescope, you will notice that each star in the pair is itself a pair of stars.  Each star in the double is double. Hence, Epsilon Lyra is known as the double double. The stars in each pair orbit a point approximately in the center of each respective pair. The pairs themselves orbit a point between the two pairs. 

Wednesday: If you want to show your loved ones a celestial sign that they should hang up their clothes, show them Brocchi's Cluster, commonly known as the Coat Hanger cluster because of its resemblance to an upside down coat hanger. The cluster is six fists above the south horizon at 11 p.m., midway between Altair and Vega, the two brightest stars in the Summer Triangle. You'll need binoculars to make out the shape. First find Altair five fists above the south horizon. Slowly move your binoculars up toward Vega. You will run into the coat hanger along the way. And while you are at it, put away your shoes. 

Thursday: Seventeenth century astronomers documented the appearance of a new star, or “nova”, in 1670. However as modern astronomers studied the records of the star, called Nova Vulpeculae 1670, they realized it didn’t have the characteristics of a typical nova because it didn’t repeatedly brighten and dim. It brightened twice and disappeared for good. Turning their telescopes to the region, they discovered the chemical signature to be characteristic of a very rare collision of two stars. For more information about this discovery, go to http://goo.gl/rJnC2G. Nova Vulpeculae 1670 is right below the binary star system Alberio, the head of Cygnus the swan. Alberio is seven fists above the south horizon at 11 p.m. 

Jupiter is a little more than a half a fist to the lower left of the Moon. They are low in the southwestern sky at 9 p.m. 

Friday: This evening, Venus is as far away from the Sun in the sky as it will get this orbital cycle. What is this "farthest away" point known as? It is known as the planet’s greatest eastern elongation. Tonight is one of the best nights of the year to observe Venus because it is far from the Sun at sunset. Venus is one fist above the west-southwest horizon at 10 p.m. Over the next two months, Venus will move toward the Sun in the sky and get closer to the horizon. By the end of September, it will be lost in the glare of evening twilight. 

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 8/4/18

Saturday:  Enjoy four planets visible to the naked eye at 9 p.m. tonight. Venus is one fist above the west horizon. Jupiter is two fists above the southwest horizon. Saturn is two fists above the south-southeast horizon. Mars is less than a half a fist above due south east. 

Sunday: Did you think you saw one of Jupiter's moons last night during your naked eye viewing of the sky? You can't see Jupiter's moons without binoculars or a small telescope. That bright point of light you see a pinky-width to the lower left of Jupiter is Zubenelgenubi, the second brightest star in the constellation Libra. Take a look again tonight at 10 p.m., one and a half fists above due southwest. 

Monday: Mizar is a well-known binary star in the constellation Ursa Major. You can find it at the bend in the Big Dipper handle, one fist above due north at 5 a.m. Its name is Arabic for waistband. Mizar has an optical double called Alcor, which is less than a pinky width away and can easily be seen with the naked eye. Optical doubles are stars that are close together in the sky but do not orbit a common center of mass as true binary stars. Not wanting to deceive sky gazers who call Alcor and Mizar a binary star, two stars that DO orbit a common center of mass, Mizar actually is a binary. It was the first binary star system discovered by telescope. Mizar A and Mizar B are about 400 astronomical units apart from each other and about 80 light years from Earth. 400 astronomical units is about 10 times the distance between the Sun and Pluto. 

Tuesday: It is not winter yet. But Orion, thought of as a winter constellation, is just above the east-southeast horizon at 5 a.m. By the actual winter, it will be visible in the evening sky.  

Wednesday: The Perseid meteor shower hits its peak for the next few early mornings with Sunday and Monday mornings being the peak of the peak. The meteors appear to come from a point just below the W of the constellation Cassiopeia. This point is about two and a half fists held upright and at arm’s length above the northeast horizon at 11 p.m. By dawn, this point is about seven fists above the northeast horizon. If you fall asleep or forget to set your alarm, you will be able to observe this shower from about 11 p.m. to dawn for the next few nights in about the same location in the sky. The Perseid shower is one of the longest lasting showers. The Moon will be new or close to new for the next few nights. For tips about optimizing your viewing this year, go to http://earthsky.org/?p=2087. As your Mother might say, dress warm and sit in a comfortable chair for maximum enjoyment. These meteors are sand to pea-sized bits of rock that fell off of Comet Swift-Tuttle. They are traveling about 40 miles per second as they collide with the Earth and burn up in the atmosphere. 

Thursday: Many big city dwellers never see the milky white, nearly continuous band of stars known as the Milky Way. As cities grow and add more lights, it has become harder to see the bulk of the Milky Way galaxy, our home in the universe. But, there are two easy ways to see the Milky Way. The first way is to look in the mirror. You are part of the Milky Way. The second way is to look from due north through the point straight overhead (called the zenith) to due south from 10:30 p.m. to 1 a.m. for the next two weeks. This is the time of year when the Milky Way is highest in the sky and away from the city lights on the horizon. 

Friday: Mars is as close to Earth and as bright as it has been in many years this summer. Enjoy the show one and a half fists above due south at midnight tonight. 

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.