Idaho Skies Transcript for the weekend of December 20th

STEPHEN

Welcome to Idaho Skies for the weekend of December 20^th. We’re your hosts, Stephen…

DAN

…and Dan.

STEPHEN

Astronomically speaking, winter begins on the 21^st at 9:19 PM. At that time, the sun appears its farthest south of Earth’s equator. With the sun that low in our sky, the days are their shortest and the sun’s light its most spread out. The combination of low sunlight intensity, short days, and long nights make our winter weather very cold.

DAN

The sun’s position in the sky drifts north during the winter and spring and then south during summer and autumn. When the sun reaches its northerly or southerly extreme, astronomers call it a solstice. The word solstice means sun standing still because on those days, the sun’s movement north and south appears to halt for a few days. 

STEPHEN

At 6:00 AM the morning after the winter solstice, stargazers will find the moon seven degrees above Mars. Seven degrees is a little less than the width of your fist when viewed at the end of your outstretched arm. Mars won’t be very bright since is 209 million miles. That’s just too far away for the reflected light of such a small planet.  

DAN

Slightly fainter and closer to the moon’s left is a star named Zubenelgenubi. That’s a funny sounding name for a star that’s really a pair of stars. Good binoculars can split this star into two. Some people in fact may have good enough vision that they can split it without optical aid. Are you one?

STEPHEN

Not me.

That’s Idaho Skies for the weekend of December 20^th.   

DAN

Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.

For Idaho Skies this is Dan…

STEPHEN

…and Stephen.

DAN

Dark skies and bright stars.

Idaho Skies Transcript for the week of December 16th

PAUL

Welcome to Idaho Skies for the week of December 16^th. We’re your hosts, Paul…

STEPHEN

…and Stephen.

PAUL

This week marks the beginning of the Ursid meteor shower. Haven’t hear of it? Well, not many people have. It’s a weak shower that only produces ten meteors per hour on average. Its parent body is comet Tuttle. And as this comet approaches the sun, the sun’s heat vaporizes the comet’s surface to release fine dust that can becomes meteors.

STEPHEN

Astronomers know that the Ursids can produce over 100 meteors per hour on occasion. That’s because the gravitational pull of Jupiter concentrates the meteor stream in places. When this is going to occur, astronomers can’t accurately predict. Therefore, it might be worth your while to look for this meteor shower occasionally this week. 

PAUL

Listeners observing this shower need to identify meteors originating from the north. Specifically, from the brightest star in the bowl of the Little Dipper. That star’s name is Kochab. Kochab is slightly fainter than its more famous brethren, Polaris on the other end of the Little Dipper.   

STEPHEN

On the morning of the 17^th, stargazers will find the nearly third quarter moon close to the star Regulus. That’s the brightest star in Leo the Lion. Then late on the night of the 18^th, you can use your binoculars to observe the craters long the terminator of the half full moon. So there are two lunar events that you can enjoy this week.

PAUL

That’s Idaho Skies for the week of December 16^th.  

STEPHEN

Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Stephen…

PAUL

…and Paul.

STEPHEN

Dark skies and bright stars.

Idaho Skies Transcript for the weekend of December 13th

BENJAMIN

Welcome to Idaho Skies for the weekend of December 13^th. We’re your hosts, Benjamin…

PAUL

…and Paul.

BENJAMIN

The moon visits Pollux, one of the Gemini Twins on the 13^th. Twin brother Pollux is the row of stars on the left and right sides of the moon. Its brightest star, also named Pollux, is on the left and it represents the head of this celestial brother. In the Gemini myth, Pollux is the immortal brother of the two. 

PAUL

This weekend, the Geminid meteor shower reaches its peak intensity. Stargazers can normally expect to see upwards of 100 meteors per hour from this shower. The meteoroids of this shower travel so fast that they create white-hot shock waves. So that meteor streak you see is really the thin atmosphere glowing white hot from the passage of the meteoroid.  

BENJAMIN

Unfortunately, the nearly full moon rises in Gemini. That’s the same constellation that the Geminid meteor shower originates from. Therefore, strong moon light will out-shine most of the meteors of this shower. Your best bet to see Geminids therefore is to look for them overhead and not in the east where the moon is located.

PAUL

On Sunday night, you’ll find the moon a short distance from the Beehive star cluster. So get your binoculars out and aim them at the moon. Then shift them downwards until the moon leaves the view at the 1 o’clock position. At the bottom of your view will be a cluster of over a dozen tightly packed stars.

BENJAMIN

That’s Idaho Skies for the weekend of December 13^th.

PAUL

Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.

For Idaho Skies this is Paul…

BENJAMIN

…and Benjamin.

PAUL

Dark skies and bright stars.

Idaho Skies Transcript for the week of December 9th

DAN

Welcome to Idaho Skies for the week of December 9^th. We’re your hosts, Dan…

BENJAMIN

…and Dan.

DAN

Because it travels around the heavens in 30 days, the moon makes a great astronomical guide. However, it’s restricted to the path taken by the sun and planets, or the constellations of the Zodiac. Since the Pleiades and Hyades star clusters are located in Taurus the Bull, the moon visits them monthly. 

BENJAMIN

So go outside on the 9^th to locate the Pleiades above the moon. Then again on the 10^th to find the moon inside the Hyades star cluster. Both star clusters are ideal binocular objects. As long as the moon’s light doesn’t interfere with the fainter stars, you’ll see at least two dozen stars in each cluster.   

DAN

Moonlight is a problem, however, because the moon is full on the 11^th. The full moon can be blinding through a telescope or even binoculars. After looking at the moon, don’t be surprised if you can’t see faint objects as well as you could before. Fortunately, this effect goes away in a few minutes.

BENJAMIN

You will hardly see any craters on the full moon. There are two reasons for this. First, when the sun is overhead, it casts few shadows. And two, Earth and the sun appear in the same place from the moon’s perspective. That means any shadows cast by sunlight are covered up by the terrain creating the shadows in the first place.      

DAN

That’s Idaho Skies for the week of December 9^th.  

BEJAMIN

Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Benjamin…

DAN

…and Dan.

BENJAMIN

Dark skies and bright stars.

Idaho Skies Transcript for the weekend of December 6th

STEPHEN

Welcome to Idaho Skies for the weekend of December 6^th. We’re your hosts, Stephen…

DAN

…and Dan.

STEPHEN

On the 8^th, Comet Borisov reaches perihelion. So let’s talk about perihelion and Comet Borisov. The word perihelion comes from the Greek “peri” and that’s the prefix meaning “about” or “around”. Think of the word perimeter as an example. And the word Helion comes from the word Helios, which is the Greek name for the sun.     

DAN

Perihelion can only occur for objects that travel in non-circular orbits. That means at perihelion, objects like Comet Borisov pass their closest to the sun. However, Comet Borisov has an orbit that’s a bit odd - it’s hyperbolic and not elliptical in shape. That means the orbit of Borisov doesn’t begin nor end in our solar system. 

STEPHEN

Comet Borisov is traveling so fast that it will escape our solar system. It didn’t pick up this speed from a close pass to another planet in our solar system. Instead, it’s traveling so fast because it escaped from another star system and fell into ours. The gravity of another object in its original solar system must have kicked it into interstellar space. 

DAN

Astronomers predict that there’s at least one interstellar visitor in our solar system at any given time. They approach the sun in a hyperbolic orbit and then fly away to never be seen again. Currently, visits by interstellar objects are the best way we can study the materials and formation of other solar systems.

STEPHEN

That’s Idaho Skies for the weekend of December 6^th.  

DAN

Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com

For Idaho Skies this is Dan…

STEPHEN

…and Stephen.

DAN

Dark skies and bright stars.

Idaho Skies Transcript for the week of December 2nd

PAUL

Welcome to Idaho Skies for the week of December 2^nd. We’re your hosts, Paul

STEPHEN

…and Stephen.

PAUL

It’s easy to be a rock star when there are no bright stars near you. And that’s definitely true for Fomalhaut, the star below the moon on the 3^rd. Astronomers rate Fomalhaut as first magnitude. It was the ancient Greeks who designed this magnitude system as a way to classify stars by their apparent brightness.

STEPHEN

They designed the magnitude system to start with a one for the brightest stars and six for the faintest the unaided eye can see. There are 17 stars brighter than Fomalhaut and some of them have negative magnitudes. For example, Sirius, the bright star rising at 9:45 PM this evening is magnitude is -1.5.   

PAUL

The moon reaches first quarter minutes before midnight of the 4^th. That means it looks so close to first quarter on the 3^rd that you won’t see the difference. First quarter occurs when the angle between the sun, Earth, and moon is 90 degrees. So the moon is nearly due south as the sun sets in the southwest.

STEPHEN

Recall that the sun always illuminates exactly half of the moon. Therefore, at first quarter we can only see half of the illuminated lunar surface. Lunar seas or lava plains cover much of the northern half that we can see and craters fill the southern half. This makes the first quarter phase the perfect moon for exploring with binoculars.   

PAUL

That’s Idaho Skies for the week of December 2^nd.  

STEPHEN

Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Stephen

PAUL

…and Paul.

STEPHEN

Dark skies and bright stars.

Idaho Skies Transcript for the weekend of November 22nd

STEPHEN

Welcome to Idaho Skies for the weekend of November 22^nd. We’re your hosts, Stephen…

BENJAMIN

…and Benjamin.

STEPHEN

The moon appears as a thin crescent 6:30 on the morning of the 23^rd. Thin moon’s like this are cool to see and are even more attractive through binoculars. But wait, it gets even better on the Saturday morning. That’s because Mars and the brightest star of Virgo the Maiden are close at hand. 

BENJAMIN

Recall that Mars currently resides on the other side of the solar system. That means it will be much fainter than it typically appears. In fact, it might be faint enough that it’s famous orange-tint may not be apparent. But still, it’s worth looking for Mars now and watching how it gets brighter over the months.  

STEPHEN

Brighter than Mars will be Spica, the lucida of Virgo. You can’t misidentify the two. Mars will be fainter of the two and below the moon. Spica will be brighter, purer white in tint, and to the moon’s lower right. Spica is actually two stars so close together that their mutual gravities warp them into egg shapes.

BENJAMIN

Stargazers not wanting to get up early will want to look in the low southwest as it’s getting dark. This weekend, Jupiter passes close to Venus with their smallest gap occurring on Sunday evening. Venus will appear much brighter than Jupiter, so it’s easy to distinguish which planet is which.

STEPHEN

That’s Idaho Skies for the weekend of November 22^nd.  

BENJAMIN

Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.

For Idaho Skies this is Benjamin…

STEPHEN

…and Stephen.

BENJAMIN

Dark skies and bright stars.

Idaho Skies Transcript for the week of November 18th

PAUL

Welcome to Idaho Skies for the week of November 18^th. We’re your hosts, Paul…

STEPHEN

…and Stephen.

PAUL

The moon reaches third quarter this week. That means the moon only appears half full. But this time, it’s the western half of the moon that appears illuminated. Like the first quarter moon, shadows along the lunar terminator really bring out terrain features like craters and mountains. So concentrate your attention there. 

STEPHEN

There’s just one problem with observing the third quarter moon – it rises so late. You’ll need to go outside at around 1:00 AM to see the moon rise over the Boise mountain range. Stargazers observing the third quarter moon see a portion few people ever see. For example, its largest lunar maria, the Ocean of Storms.

PAUL

The Ocean of Storms fills the entire left edge of the moon. It’s the landing location of Apollo 12 back on late 1969. The crater of the ocean’s right edge is called Copernicus. It’s an impact scar 57 miles across. Astronomers estimate that the crater is relatively young at 800 million years old. That’s young for the moon.

STEPHEN

Moon watchers will find the third quarter moon inside Leo the Lion on the morning of the 20^th. Leo’s brightest star, Regulus is located to the moon’s right. The lion’s mane is the question mark of stars above Regulus. Farther away to the left is fainted Denebola. Denebola represents the base of Leo’s tail. 

PAUL

That’s Idaho Skies for the week of November 18^th.  

STEPHEN

Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Stephen…

PAUL

…and Paul.

STEPHEN

Dark skies and bright stars.

Idaho Skies Transcript for the week of November 11th

BENJAMIN

Welcome to Idaho Skies for the week of November 11^th. We’re your hosts, Benjamin…

DAN

…and Dan.

BENJAMIN

The full moon travels past two bright and large star clusters this week. The first cluster is the Pleiades. You probably know the Pleiades as the Seven Sisters, but astronomers have an official designation, M-45. M-45 is a close star cluster. So it appears large and bright in the night sky. The moon will make a distant pass of the cluster later this week.  

DAN

Get your binoculars and observe M-45. Be sure to compare the view of the Pleiades to your unaided eye and through binoculars. If you’re like most people, you’ll see six or maybe seven stars with just your eyes. However, with binoculars the number of stars explodes. You might see as many as two dozen glittering stars.

BENJAMIN

On the 13^th, our moon makes it way to the Hyades star cluster. The Hyades are closer to our solar system then the Pleiades. Unfortunately, the star cluster is sparser and therefore, less dazzling. Still, binoculars will show stargazers some two dozen stars in this cluster. But don’t be fooled by its brightest star. 

DAN

The ancients named the brightest star of Taurus Aldebaran. And it just so happens to appear in the same view as the Hyades. However, Aldebaran is only half as far away as the Hyades. So from Earth, it only looks like Aldebaran is a member of the Hyades. Because of its reddish tint, people consider Aldebaran to be the eye of Taurus the Bull.

BENJAMIN

That’s Idaho Skies for the week of November 11^th.  

DAN

Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is DAN…

BENJAMIN

…and Benjamin.

DAN

Dark skies and bright stars.

Idaho Skies Transcript for the weekend of November 15th

DAN

Welcome to Idaho Skies for the weekend of November 15^th. We’re your hosts, Dan…

PAUL

…and Paul.

DAN

This weekend the moon passes through Gemini the Twins and ends up in Cancer the Crab. On Friday, the moon appears next to Castor’s knee and foot. Since Gemini rises in the east lying on its side, Castor is the top twin this weekend. Castor is also the name of the fainter of the two brightest stars making up Gemini.

PAUL

On Saturday night, you’ll find the moon closer to the head of Pollux, the lower and brighter star of the Heavenly Twins. It’s odd that astronomers named Pollux Beta Geminorum. Because calling a star the beta star of a constellation typically signifies that its second brightest star.   

DAN

While it doesn’t take a pair of binoculars to see Castor or Pollux, the moon’s neighbor on Sunday will. If you aim your binoculars at the moon at around 11:30 PM, you’ll find a scattering of stellar gems just below it. That’s the Beehive star cluster and it’s even visible without optical aid in very dark skies. 

PAUL

Many ancient cultures were aware of the Beehive. Some of them referred to this tiny cloudy spot as a manager. They called objects like the Beehive a nebula, which means small cloud. Galileo was the first to discover that optical aid turned the Beehive into a star cluster in 1609. 

DAN

That’s Idaho Skies for the weekend of November 15^th.

PAUL

Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.

For Idaho Skies this is Paul…

DAN

…and Dan.

PAUL

Dark skies and bright stars.

Idaho Skies for the Weekend of November 8th

STEPHEN

Welcome to Idaho Skies for the weekend of November 8^th. We’re your hosts, Stephen…

BENJAMIN

…and Benjamin.

STEPHEN

The Red Planet recently traveled to the other side of the sun from our perspective. That means it now reappears as a morning planet. So stargazers looking for Mars need to check out the low south-southeast sky at around 6:30 AM. However, don’t be surprised to by the faintness of Mars.

BENJAMIN

Mars is 230 million miles away. In addition, the planet has a dark surface that only reflects 29% of the sunlight shining on it. That means the small, dark, and distant Mars is decidedly faint these days. But that will change over the next two years. Earth and Mars are in a cosmic race. And Earth will soon catch up to and pass Mars.

STEPHEN

Astronomical events like this are called oppositions. They’re the times when two planets are their closest together. As a result, the planets are larger and brighter than usual. In fact, Mars will be 15 times bright in October 2020 than it is now. By the way, oppositions make good times to launch spacecraft to Mars.  

BENJAMIN

Mars is not large enough for binocular viewing, even at opposition. However, observers using amateur telescopes may be able to see the surface features on the red planet. These features include clouds on Mars’ largest volcano, Olympus Mons and other exotic-sounding locations like Syrtis Major.  

STEPHEN

That’s Idaho Skies for the weekend of November 8^th.  

BENJAMIN

Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com

For Idaho Skies this is Benjamin…

STEPHEN

…and Stephen.

BENJAMIN

Dark skies and bright stars.

Idaho Skies Transcript for the Week of November 4th

PAUL

Welcome to Idaho Skies for the week of November 4^th. We’re your hosts, Paul

STEPHEN

…and Stephen.

PAUL

The waxing gibbous moon appears in the south these evenings. Unfortunately, it’s a region of the sky that’s sparsely filled with stars. What is there tends to be faint. So many stars are not visible from town, let alone in dark skies south of Boise. There is one exception, however.

STEPHEN

That exception is Fomalhaut. Fomalhaut represents the mouth of the Southern Fish, or Piscis Austrinus. It’s not that this star is intrinsically bright that makes it so visible from Earth. It’s the fact that Fomalhaut is only 25 light years away. Only 26 visible stars are closer to the solar system than Fomalhaut.

PAUL

Fomalhaut means Mouth of the Fish, or Whale in Arabic. To the Persians, it was known as Hastorang and consisted one of four royal stars. Its Chinese name means North Gate of the Military Camp. And the natives of Northern Australia named it the White Cockatoo. What these people didn’t know is that the star has two other companion stars.

STEPHEN

Astronomers named brightest companion star of Fomalhaut TW Piscis Austrini. Although distant from Fomalhaut, its motion through space show it moves in the identical speed and direction as its brighter companion. The distance between them is nearly one light year. Its other companion is 2.5 light years away.  

PAUL

That’s Idaho Skies for the week of November 4^th.

STEPHEN

Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Stephen

PAUL

…and Paul.

STEPHEN

Dark skies and bright stars.

Idaho Skies Transcript for the Weekend of November 1st

BENJAMIN

Welcome to Idaho Skies for the weekend of November 1^st. We’re your hosts, Benjamin…

STEVEN

…and Steven.

PAUL

The moon continues its very low traverse of the sky this weekend. However, it will help stargazers locate Saturn.

BENJAMIN

Saturn, like the other visible planets, appears as a star. In this case, it’s a dim star with a slightly yellowish tint to it. And like the other planets, it’s resistant to twinkling. So look for the brightest star to the crescent moon’s left. That’s Saturn. Sadly, Saturn is not a binocular object like the moon.

STEVEN

The moon and Saturn are polar opposites of each other. Our moon is a small rocky world with virtually no air or water. Saturn is the second largest planet of the solar system and primarily made of gases, including water. Any solid surface on Saturn lies very deep within the planet.

BENJAMIN

When you look at the moon through binoculars or telescope, you’re seeing a rocky world. Its surface is blemished with crater impacts of frozen seas of magma, or lava rock. It’s different for Saturn. A telescope only shows a gaseous atmosphere that gradually thickens into a hot liquid of hydrogen and helium.

STEVEN

A telescope capable of magnifying at least 25 times is enough to show the rings of Saturn. It will also show you its largest moon, Titan. The rings are bright and broad, so there’s no mistaking them. Titan on the other hand is star-like. So look for a star near Saturn that shifts position the next day.

PAUL

Spend a little time this week checking out the waxing moon and Saturn. And don’t forget that Jupiter is closer to the lower west.    

BENJAMIN

That’s Idaho Skies for the weekend of November 1^st.

STEVEN

Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com

For Idaho Skies this is Steven…

BENJAMIN

…and Benjamin.

STEVEN

Dark skies and bright stars.

Idaho Skies Transcript for the week of October 28th

STEVEN

Welcome to Idaho Skies for the week of October 28^th. We’re your hosts, Steven…

DAN

…and Dan.

PAUL

The moon is new on Monday. That means this week, we’ll see the moon reappear in the west-southwest after sunset.

STEVEN

However, you’ll need to wait a few days before it appears. That’s because the moon’s path across the sky is relatively flat with respect to the western horizon. The sun and planets follow a path across the stars called the ecliptic. For the most part, the ecliptic traverses the constellations making up the Zodiac.

DAN

The moon however orbits in a tilted orbit with respect to the ecliptic. The inclination is five degrees, so not too crazy. However, it’s still enough to make the moon deviate significantly from places in the sky where the planets can reside. There’s a name describing where the moon is relative to the ecliptic.

STEVEN

When the moon’s position in its tilted orbit is below the equator, we say the moon is running low. When the moon is on the half of its orbit that’s on its northernly side, we say the moon is riding high. Only when the moon is between these two extremes can we have solar and lunar eclipses.

DAN

The moon reappears on the 30^th, stargazers will find it very low in the southwest. More apparent will be Jupiter, a bright looking star. The moon will be to the lower left of Jupiter and a very thin crescent. These two objects, Jupiter and the waxing crescent moon will make ideal binocular objects.

PAUL

Enjoy moon watching this week. Because the moon runs low this week and its orbit is strongly tilted relative to the horizon, we won’t see it until its three days after full on Thursday evening.      

STEVEN

That’s Idaho Skies for the week of October 28^th.  

DAN

Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Dan…

STEVEN

…and Steven.

DAN

Dark skies and bright stars.

Idaho Skies Transcript for the weekend of October 25th

STEVEN

Welcome to Idaho Skies for the weekend of October 25^th. We’re your hosts, Steven…

BENJAMIN

…and Benjamin.

PAUL

This weekend gives stargazers opportunities to see three terrestrial planets. They’re Mercury, Venus, and Mars.

STEVEN

Let’s start with the innermost planets, Mercury and Venus. When Mercury or Venus appear their highest above the horizon, astronomers call it an apparition. Unfortunately, many apparitions of Mercury are not very good. That’s because it orbits the too closely and its orbit appears inclined to our horizon.

BENJAMIN

Our best view of Mercury is on the days around the 25^th. You’ll have many days to see Mercury, so there’s no problem its cloudy. Mercury won’t be very bright, Venus in fact will stand out more than Mercury. So look left of the Evening star at around 7:00 PM for Mercury.

STEVEN

Mars is not an evening planet right now. So only stargazers who observe the sky during the morning are going to locate the planet. Saturday morning would be a great time because the moon will be close by. Now Mars won’t be very bright, and the moon will be a very narrow crescent.

BENJAMIN

So look in the very low east at about 7:00 AM. The moon’s narrow crescent may be filled in with sunlight that has reflected off of Earth. Mars will be the faint star beneath the moon and slightly right. Their distance apart will be 1.5 degrees. That’s three times the moon’s apparent diameter. 

PAUL   

Stargazers with an interest in planets will enjoy this weekend. Don’t forget however, that Jupiter and Saturn will also be visible in the evening after dark. Just look in the low south and southeast.

STEVEN

That’s Idaho Skies for the weekend of October 25^th.

BENJAMIN

Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.

For Idaho Skies this is Benjamin…

STEVEN

…and Steven.

BENJAMIN

Dark skies and bright stars.

Idaho Skies Transcript for the week of October 21st

DAN

Welcome to Idaho Skies for the week of October 21^st. We’re your hosts, Dan…

BENJAMIN

…and Benjamin.

PAUL

Leo the Lion is a prominent spring-time constellation. However, early-rising stargazers will find that the Lion has lunar company on the morning of the 23^rd.

DAN

To identify Leo, look first for its brightest star, Regulus. Regulus, which is the brightest star below the moon is the 21^st brightest star. It’s a giant star that’s 79 light years away. Your binoculars will show two stars in place of the one your eye sees. A good telescope splits the second star into two stars.

BENJAMIN

Regulus is a giant star. It’s nearly four times more massive than the sun and three times wider. It also rotates more quickly than our sun. The sun, or Sol, takes 27 days to revolve once on this axis. Of course, this has nothing to do with the length of the month. Regulus, on the other hand, rotates once in 16 hours.

DAN

Rotating 41 times faster than the sun puts a strain on Regulus. So much in fact that the star bulges noticeably at its equator. If it rotated any faster, Regulus would tear itself apart. Its gravity would be unable to hold onto material at its equator. None of this is obvious in your binoculars, or course.

BENJAMIN

Once you’ve located Regulus, the rest of Leo is easy to find. Its mane is the backwards question mark of five stars above Regulus. The hind quarters of Leo are the three-star triangle to the left of Regulus. This means Regulus represents the heart of Leo. Maybe this is why Regulus means little king.

PAUL

So on Wednesday morning, take a few minutes to look for the moon and Regulus below it. The rest of Leo will be above and left of the moon.

DAN

That’s Idaho Skies for the week of October 21^st.

BENJAMIN

Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Benjamin…

DAN

…and Dan.

BENJAMIN

Dark skies and bright stars.

Idaho Skies Transcript for the weekend of October 18th

BENJAMIN

Welcome to Idaho Skies for the weekend of October 18^th. We’re your hosts, Benjamin…

STEVEN

…and Steven.

PAUL

Saturday night the moon appears close to a star cluster named M-35. It’s in the constellation of Gemini the Twins.

BENJAMIN

The Gemini brothers are named Castor and Pollux. Their mother was Leda, a mortal woman and wife of king Tyndareus. Her twin sons had two fathers, her husband the king and Zeus, the king of the Greek gods. Castor was mortal while his brother Pollux was immortal.

STEVEN

The constellation appears on its side during October. Its two brightest stars are located on the north end of the constellation and named after each twin. The brightest star and the one closer to the horizon is Pollux. While the slightly fainter star above Pollux is Castor.

BENJAMIN

Castor is called the alpha star of the constellation, even though it’s the second brightest. Castor appears as a single star, but is actually three pairs of binary stars. That means six stars are orbiting each other in the Castor star system. At 51 light years away, Castor appears as a triple star in a good telescope.

STEVEN

On the evening of the 19^th, a pair of binoculars aimed at the gibbous moon will also show you the M-35 star cluster. The cluster will appear as a hazy spot in dark skies. Its location will be left of the moon. However, you’ll want to shift your binoculars to the left to remove the moon form your field of view.      

PAUL

Be sure to check out Gemini the Heavenly Twins this weekend. They will appear to be lying on their side in October, but standing upright this spring.

BENJAMIN

That’s Idaho Skies for the weekend of October 18^th.

STEVEN

Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.

For Idaho Skies this is Steven…

BENJAMIN

…and Benjamin.

STEVEN

Dark skies and bright stars.

Idaho Skies Transcript for the week of October 14th

DAN

Welcome to Idaho Skies for the week of October 14^th. We’re your hosts, Dan…

STEVEN

…and Steven.

PAUL

The moon spends this week traveling past large star clusters. Although craters will not be very visible on the gibbous moon, the star clusters are still nice binocular targets.

DAN

The first star cluster is the called the Pleiades. You might know it as the Seven Sisters. The name Pleiades comes from the Greek verb for to sail. When the Pleiades rose just before sunrise, it was time for the Greek to begin sailing in the Mediterranean Sea. Until the weather was settled, it was too dangerous to sail.

STEVEN

The sisters are the daughters of the Greek titan, Atlas. Atlas choose the wrong side in the war between the older titans and the younger gods like Zeus. As a consequence, he was condemned to spend the rest of eternity supporting the heavens on his back. He was eventually rescued from this curse by being turned into stone.

DAN

The seven sisters are named Sterope, Merope, Electra, Maia, Taygeta, Celaeno, and Alcyone. The brightest is Alcyone. The distance to the star cluster is 444 light years. So the light you see tonight left in the year 1575. Astronomers have determined that the star cluster formed within the last 100 million years.     

STEVEN

Galileo was the first person to turn a telescope to the Pleiades. He was surprised to find some three dozen stars when most people can only six or seven member stars. You can see the cluster like Galileo did by aiming your binoculars at the star cluster this week. Can you see as many stars as Galileo?

PAUL

Enjoy viewing the Pleiades star cluster with your binoculars this week. And don’t forget to look at the Hyades star cluster, which the moon passes on the 16^th. 

DAN

That’s Idaho Skies for the week of October 14^th.  

STEVEN

Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Steven…

DAN

…and Dan.

STEVEN

Dark skies and bright stars.

Transcript for the Weekend of October 11th

STEVEN
Welcome to Idaho Skies for the weekend of October 11th. We’re your hosts, Steven...

BENJAMIN
...and Benjamin.

PAUL
Hey, the moon is full on Sunday the 13th. That makes this weekend a great time to learn about the difference between lunar maria and highlands. 

STEVEN
Current understanding suggests that the moon, or Luna, formed after the impact of a Mars-sized object with the newly born Earth. Since the impact was glancing, it blasted a lot of Earth’s outer layer, or mantle into space. The minerals in the mantle rock tend to have a low density.

BENJAMIN
The vaporized rock the impact let in orbit around Earth was low in iron. That created a moon that was light whitish in color, once it cooled, that is. We see this material in in the brighter parts of the moon. And since it originated with the impact, lunar areas that are brighter in color are around 3.8 billion years old.

STEVEN
Three point eight billion years ago, the solar system was still swarming with planetary building blocks, or planetesimals. These giant meteoroids occasionally slammed into the moon creating huge craters called impact basins. Impact basins also deeply cracked the lunar crust. 

BENJAMIN
After the moon’s surface cooled, its interior remained warm. Partly from the initial impact but also from radioactive decay. The warm interior created magma or lava that welled up into the impact basins. Layer after layer of dark lava filled the impact basins to create mostly dark circular features.

PAUL
So the moon started out as a light-colored body that was repeatedly smashed in horrific impacts. These then filled in with darker lava to create the lunar seas and the Man-on-the-Moon face we enjoy today.       

STEVEN
That’s Idaho Skies for the weekend of October 11th. 

BENJAMIN
Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com

For Idaho Skies this is Benjamin...

STEVEN
...and Steven.

BENJAMIN
Dark skies and bright stars.

Transcript the Week of October 7th

STEVEN
Welcome to Idaho Skies for the week of October 7th. We’re your hosts, Steven...

DAN
...and Dan.

PAUL
Autumn skies are filled with constellations representing watery themes. Unfortunately, they contain stars that are mostly dim.

STEVEN
The moon swims through these constellations this week. The first constellation of note is Capricornus. This constellation represents a chimera of a goat and fish. Hence, it’s called the sea goat. In dark skies. Capricorn looks like a grinning mouth. Over two thousand years ago, the sun was in Capricornus on the first day of winter. 

DAN
East of Capricornus is an even fainted constellation named Aquarius. The aqua in Aquarius obviously means water in Latin. The last half of the name means carrier. So Aquarius is the water carrier of bearer. He’s depicted as pouring a jar or vase of water, with the vase being a circle of stars.

STEVEN
The water of Aquarius flows south into the mouth of the Southern Fish which astronomers call Piscis Austrinus. The brightest star of Piscis Austrinus is visible below the moon on the evening of the 9th. The star’s name is Fomalhaut. It’s close to the solar system compared to other stars.

DAN
Fomalhaut is a young star; astronomers estimate it’s only 400 million years old. Fomalhaut has the distinction of the being the first solar system imaged from Earth. Back in 2008, the Hubble Space Telescope was able to see a planet orbiting Fomalhaut. The planet is roughly Jupiter size.         

PAUL
Don’t be surprised you can’t see many stars in the south these evenings. But do take advantage of the moon on the 9th to find the brightest star, Fomalhaut.

STEVEN
That’s Idaho Skies for the week of October 7th.

DAN
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Dan...

STEVEN
...and Steven.

WHO
Dark skies and bright stars.

Idaho Skies Transcript for May 20th and 21st

RACHEL
Welcome to Idaho Skies for May 20th and 21st. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
Today we celebrate astronomer Williamina Fleming.

PAUL
She was born in Scotland on May 15th, 1857 and died in the United States on May 21st, 1911. She started working as a maid at the Harvard Observatory at age 21. The observatory’s director later assigned her to clerical work and then finally as a computer. In the late 19th century, computers were people, usually women, who performed mathematical calculations for scientists. 

RACHEL
Astronomers at the time were trying to create a classification scheme for stars. There isn’t enough information in just the color of a star, but there is if you split its colors up with a spectroscope. So astronomers spent minutes and even hours photographing stars though a spectroscope. 

PAUL
The lines appearing in a star’s spectrum indicates the elements in its outer atmosphere. There’s also information on the star’s surface temperature buried within its spectra. However, astronomers needed a meaningful way to classify these spectra. And Ms. Fleming determined to way to do this based on the amount of hydrogen displayed in each star’s spectra. 

RACHEL
Willimina also famous to discovering a very faint star that was intensely hot. Hot stars tend to be bright stars. Since it wasn’t bright, the star had to be very small. On the order of planet small. These dense white-hot stars were eventually named white dwarfs and they represent the end of life for low mass stars like the sun.

PAUL
That’s Idaho Skies for the 20th and 21st of May.

RACHEL
Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com

For Idaho Skies this is Rachel…

PAUL
…and Paul.

RACHEL
Dark skies and bright stars.

Potential Auroras

Sunspot AR2741 is an active site on the sun. It's hurled a coronal mass ejection (CME) our way that could result in Idaho seeing the Northern Lights. so be on the look out Wednesday and Thursday nights. 

Sunspot AR2741

Sunspot AR2741 is larger than Earth. In this image, you can see the darker umbra and that it's surrounded by a lighter penumbra.

Idaho Skies Transcript for May 17th, 18th, and 19th

PAUL
Welcome to Idaho Skies for May 17th, 18th, and 19th. We’re your hosts, Paul...

RACHEL
...and Rachel.

BRING DOWN MUSIC
PAUL
On our last show, we mentioned that there was a cluster of galaxies residing in Virgo.
   
RACHEL
Galaxy clusters consist of hundreds to over a thousand galaxies bound together by their mutual gravity. The combined mass of all the stars inside a galaxy cluster can equal one quadrillion times the mass of our sun. From one end to the other, they can stretch tens of millions of light years across.
 
PAUL
Greater than the mass of all the stars in all the galaxies of a galaxy cluster is the gas trapped between them. Galaxy clusters have almost ten times as much gas than stars. Massive black holes inside the centers of the galaxies heat the gas until it emits x-rays.

RACHEL
Did you know that galaxy clusters are not the largest structures in the universe? Galaxy clusters combine with others to create superclusters. Let’s start with our puny little Milky Way galaxy. It’s only 100,000 light years across. It belongs to the Local Group of 54 galaxies, including the Andromeda Galaxy.

PAUL
Our Local Group is an outlying member of the Virgo Cluster. The Virgo Cluster on the other hand is just but a part of the Laniakea Supercluster. Our Local Group of 54 galaxies only spans 2% of the Laniakea Supercluster’s 500 million light year diameter. Astronomers estimate that there are 100,000 galaxies in the Laniakea Supercluster. 

RACHEL
That’s Idaho Skies for the 17th, 18th, and 19th of May.

PAUL
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.
For Idaho Skies this is Paul...

RACHEL
...and Rachel.

RACHEL
Dark skies and bright stars.

Idaho Skies Transcript for May 15th and 16th

RACHEL
Welcome to Idaho Skies for May 15th and 16th. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
The evening sky during spring is devoid of bright stars.

PAUL
In fact, the only event this week involving the moon and bright stars occurs on the 15th when the gibbous moon appears above Spica. Spica is the brightest star of Virgo the Maiden. The star is a giant binary star 250 light years away. To be visible that far away, it must be 20,000 times brighter than the sun.

RACHEL
The mythology of Virgo associates her as a goddess of either harvest or of justice. So it’s not surprising that her brightest star, Spica is named after an ear of grain. And as a goddess of justice, it’s not surprising that her neighboring constellation is Libra the Scales.

PAUL
Our listeners won’t see very many stars surrounding Spica. Although Virgo is a large constellation, it’s filled with widely-spaced dim stars. The reason why this region of the sky is so blank is that points up through the North Pole of the Milky Way galaxy. That means we’re looking though less galactic volume during spring nights.

RACHEL
On the other hand, with fewer stars comes less obscuring gas and dust. As a result, astronomers can see more galaxies in this region of the sky. For example, the Virgo Cluster is a gravitationally-bound cluster of over 1,000 galaxies. Its center lies 53 million light years away.

PAUL
That’s Idaho Skies for the 15th and 16th of May.

RACHEL
Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.
For Idaho Skies this is Rachel...

PAUL
...and Paul.

RACHEL
Dark skies and bright stars.