Transcript for February 1st to 7th

RACHEL
Welcome to Idaho Skies for the first week of February. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
After it gets dark on the 2nd, look for the Beehive star cluster to the moon’s left.

PAUL
The Beehive is among the largest of the star clusters and is located just beyond a binocular’s field of view from the moon.

RACHEL
That means you need to place the moon just outside the right side of your binoculars.

PAUL
Then the star cluster will appear on the very left edge of your field of view.

RACHEL
And the cluster is nice in binoculars and appears three times larger than the moon appears.

PAUL
Did you know you can see this cluster in dark skies, like those found outside of town?

RACHEL
It appears as a faint fuzzy cloud.

PAUL
The ancient Greek astronomer Aratus could see it and named it the Little Mist back in 270 BC.

RACHEL
Hey, what’s that bright star to the left of the moon on the 3rd?

PAUL
It’s not a star, it’s the planet Jupiter.

RACHEL
You should notice that Jupiter has a slightly off-white tint.

PAUL
And that it will resist twinkling unlike its surrounding stars.

RACHEL
Jupiter is even larger and brighter this week than on average.

PAUL
Why is that?

RACHEL
That’s because Jupiter reaches opposition on the 6th.

PAUL
Oh, that’s when Jupiter is located opposite the sun in our sky.

RACHEL
That’s right and it means that Jupiter is its closest to Earth.

PAUL
So as a consequence, Jupiter is larger and brighter than average.

RACHEL
If you have any sort of optical aid, even a pair of binoculars, then aim it at Jupiter.

PAUL
You’ll see two stars forming a straight line with Jupiter, and Jupiter in the middle.

RACHEL
In your binoculars, the bottom star is Callisto and the top star is Ganymede.

PAUL
Ganymede is the largest satellite in the solar system.

RACHEL
Would you be surprised to hear that it’s even larger than the planet Mercury?

PAUL
That’s right; our solar system has a moon that’s larger than a planet.

RACHEL
The yellowish star to the moon’s left on the 4th is Regulus.

PAUL
Regulus is the brightest star of Leo and Lion and it represents the lion’s heart.

RACHEL
The star forms the bottom of a backwards question mark of six stars.

PAUL
You should be able to see these stars as long as you’re not in downtown Boise.

RACHEL
The question mark pattern of stars above Regulus represents the back of Leo’s head and his mane.

PAUL
The rest of Leo is a triangle of three stars located a short distance to the east.

RACHEL
Star maps illustrate Leo setting like the Great Sphinx of Egypt.

PAUL
That’s Idaho Skies for the first week of February. Next week we’ll talk about the brightest star in the sky.

RACHEL
Be sure to follow us on Twitter at Idaho Skies for this week’s event reminders and sky maps.

For Idaho Skies this is Rachel...

PAUL
...and Paul.

RACHEL
Dark skies and bright stars.

February's Star is Sirius

This month look for the star Sirius. Sirius is the lucida of the constellation of Canis Major, the Big Dog and its half way up in the sky when you face towards the southwest during February nights. It’s the brightest star in the heavens and only the planets Venus, Mars, and Jupiter can surpass its nighttime brilliance. Sirius is a bright white star that appears to throw off sparks of color when it’s low to the horizon. That’s because there’s more atmosphere low in the horizon to refract its starlight. If you were born in 2006, then Sirius is your birthday star this year because the light you see tonight left Sirius 9 years ago. The name Sirius comes from the Greek word for scorching. During the Dog Days of summer, which occurs in early August, the sun and Sirius are close together in the sky. The Greeks believed that the heat of Sirius added to the sun’s heat, making these days especially hot.  

Sirius has a strange companion. Back in the early 19th century, astronomers discovered that the star wobbled back and forth as it slowly drifted across the sky. It was as if the gravity of a massive star was tugging on it. However, try as they might, no astronomer could discover a star close to Sirius to account for its wobbly motion. It wasn’t until 1854 when Alvan Clark turned a new 18 inch refracting telescope to the star that he discovered a tiny spark of a star next to Sirius. The star was not really that faint, but its closeness to Sirius made it impossible to see with previously telescopes.

The companion to Sirius, called the Pup Star, orbits Sirius with a period of fifty years. From the amount of tugging Sirius experiences from this star, we know that the Pup Star has a mass equal to our sun. What’s so surprising is that if we viewed the sun from nine light years away, we would easily see it with the unaided eye. However, the Pup Star isn’t. What gives?  Stars like the Pup Star have the spectrum of a very hot star. Therefore, every square foot of these stars is more intense than an equal area of our sun. The low total brightness but high surface intensity of these types of star tells astronomers that they must be very tiny, about the size of our planet. We call them White Dwarf stars.

Once each white dwarf was like our sun, moderately bright and moderately large. Once its nuclear fuel ran out, the star collapsed on itself because it could no longer support its weight using nuclear fusion. Only the repulsion between electrons keeps white dwarf stars from collapsing any smaller. The compression of a star into a white dwarf makes it incredibly dense. A billiard ball of white dwarf weighs as much as a tank, or about the same weight as 100 family cars.      

Transcript for January 25th to 31st

PAUL
Welcome to Idaho Skies for the last week of January. We’re your hosts, Paul...

RACHEL
...and Rachel.

PAUL
This is star cluster week.

RACHEL
So get your binoculars ready.

PAUL
The moon forms a triangle with the Hyades and Pleiades star clusters on the night of the 28th.

RACHEL
Bright star clusters are perfect objects for your binoculars or spotting scope.

PAUL
While the fainter ones will appear as fuzzy spots...

RACHEL
...the brighter ones can appear as a scattering of diamond dust.

PAUL
Star clusters formed from one giant cloud of dust and gas.

RACHEL
A disturbance, perhaps a supernova shockwave creates a wave of compression that lets gravity’s attraction overcome the random motions of the molecules inside the cloud.

PAUL
When this happens, the cloud shrinks and fragments into many pieces.

RACHEL
Each fragment shrinks into a spinning pancake of dust and gas.

PAUL
As it gets smaller, the cloud of gas grows ever hotter.

RACHEL
At some point, the center of the cloud gets hot enough to start fusing hydrogen into helium.

PAUL
The remaining dust and gas fragments into smaller pieces that eventually collapse into planetesimals, or the building blocks of planets.

RACHEL
Planetesimals collide with each other as they orbit the new born sun.

PAUL
Many of them will stick together to build larger structures that will eventually become planets.

RACHEL
Our solar system most likely formed in such a way 4.5 billion years ago.

PAUL
Unfortunately, the sun’s siblings drifted away long ago.

RACHEL
The moon drifts past the edge of the Hyades star cluster on the 29th.

PAUL
The Hyades appears as a large triangle of stars.

RACHEL
Look for the orange star at the end of the triangle nearest the moon.

PAUL
The star is not actually a member of the Hyades star cluster.

RACHEL
It’s much closer to our solar system than the Hyades.

PAUL
And it just happens to lie in a line between our solar system and the Hyades star cluster.

RACHEL
The star’s name is Aldebaran and it represents the glowing red eye of Taurus the Bull.

PAUL
Aldebaran means the follower in Arabic.

RACHEL
Why the follower?

PAUL
Probably because the star follows the Pleiades star cluster.

RACHEL
That’s Idaho Skies for the last week of January. Join us next month for the space and astronomy events for Idaho.

PAUL
Be sure to follow us on Twitter at Idaho Skies for this week’s event reminders and sky maps.

For Idaho Skies this is Paul...

RACHEL
...and Rachel.

PAUL
Dark skies and bright stars.

Transcript for January 11th to 17th

PAUL
Welcome to Idaho Skies for the second week of January. We’re your hosts, Paul...

RACHEL
...and Rachel.

PAUL
Venus is visible once again as the Evening Star.

RACHEL
And it has a friend for the next two weeks.

PAUL
Look low in the southwest at 6:00 PM on the 11th for Venus; it’s the brightest star in that part of the sky.

RACHEL
Just located to the right of Venus is a fainter star that’s actually the planet Mercury.

PAUL
A pair of binoculars is useful for observing this duo.

RACHEL
But please be careful, don’t use your binoculars until after the sun sets.

PAUL
A relatively bright star appears just below the moon on the morning of the 13th.

RACHEL
The star is Spica, the alpha star of Virgo the Maiden.

PAUL
The distance between the moon and Spica is 2.5 degrees, or about five times the moon’s apparent diameter.

RACHEL
That means the pair will fit nicely within the field of view of your binoculars.

PAUL
Spica is the 15th brightest star and its 250 light years away.

RACHEL
However, Spica is not just one star.

PAUL
That’s right; it’s actually a pair of giant stars orbiting each other in just four days.

RACHEL
The stars orbit each other so quickly because they’re very close together.

PAUL
They’re so close that their gravity stretches them into egg-shapes.

RACHEL
Mercury reaches it greatest distance from the sun on the night of the 14th.

PAUL
Astronomers call this Mercury’s greatest eastern elongation.

RACHEL
In astronomy talk, that means Mercury appears as far east of the sun as possible.

PAUL
So as its getting dark at 6:00 PM, look for Mercury just right of brighter Venus.

RACHEL
The pair will be 10 degrees above the southwest horizon, which is about twice the angle your binoculars can see.

PAUL
Saturn and the moon appear just one degree apart on the morning of the 16th.

RACHEL
So as you drive to work on Friday morning, look for a star to the moon’s right.

PAUL
If you’re not driving to work that morning and you have a telescope, then take a few minutes to look at Saturn.

RACHEL
Even at low power, the planet’s rings are visible as a yellowish disk surrounding Saturn’s equator.

PAUL
Don’t confuse for an orangish star below the moon.

RACHEL
That’s a real star, the red giant Antares.

PAUL
Antares is the brightest star of Scorpius the Scorpion.

RACHEL
It represents the heart of the scorpion and its just over 600 light years away.

PAUL
That means the light you see tonight left in the year 1410.

RACHEL
That’s Idaho Skies for the second week of January. Next week you have the opportunity to see a very young moon and Earthshine.

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

RACHEL
...and Rachel.

PAUL
Dark skies and bright stars.

Transcript for January 4 - 10

RACHEL
Welcome to Idaho Skies for the first week of January. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
The first major meteor shower of the year reaches its peak on the night of the 3rd and morning of the 4th.

PAUL
It’s the Quadrantid meteor shower and we can expect to see as many as 45 bluish meteors per hour.

RACHEL
Unfortunately, the moon is one day from full.

PAUL
Which means its light will interfere with some of the fainter meteors.

RACHEL
However, the average brightness of the shower’s meteors is pretty high.

PAUL
So there’ll still be plenty of meteors to see.

RACHEL
If you plan to watch the Quadrantids, be sure to dress warmly and watch for meteors originating from the low north.

PAUL
The moon leads you to nice star clusters on the 9th.

RACHEL
The clusters are located in the constellation of Cancer the Crab.

PAUL
To find them, point your binoculars at the moon at around 9:00 PM.

RACHEL
Approximately half a binocular field of view below the moon is a small star cluster named M-67.

PAUL
It’s not very difficult to see the cluster as a fuzzy patch, but you’ll need to lower your binoculars a little bit further.

RACHEL
That way the moon’s light won’t wash out the star cluster.

PAUL
A much easier to see star cluster is the Beehive star cluster, however.

RACHEL
And you’ll find it to the upper left of the moon.

PAUL
The distance between the Beehive star cluster and the moon is just over a binocular field of view.

RACHEL
So place the moon in the lower right edge of your binoculars.

PAUL
Then you’ll see the star cluster in the upper left corner of your binoculars.

RACHEL
The Beehive star cluster is visible to the unaided eye in the dark skies that you’ll find outside of Boise.

PAUL
It appears just like it did to the ancients, a small fuzzy spot in the sky.

RACHEL
Searching for Jupiter?

PAUL
Then look for the moon after 8:30 PM on the 7th.

RACHEL
The bright star located to the moon’s upper left is Jupiter.

PAUL
You may notice that Jupiter doesn’t twinkle like the other bright stars.

RACHEL
That’s because Jupiter’s large size lets it average out all the brightness fluctuations caused by moving pockets of air.

PAUL
This is pretty much true for all the planets.

RACHEL
Even though stars have much larger disks than the planets, they’re so far away that they appear smaller than pin points of light.

PAUL
As a result, even small pockets of moving air can twist and bend the beams of starlight enough to make their color and brightness fluctuate.

RACHEL
You can see all four of Jupiter’s large satellites through a spotting scope.

PAUL
From bottom to top, you’ll see Io, Jupiter, Europa, Ganymede, and Callisto.

RACHEL
They’ll form a compact group, so you might not be able to separate the satellites as well through a pair of binoculars.

PAUL
That’s Idaho Skies for the first week of January. Several planets make the news next week.

RACHEL
Be sure to follow us on Twitter at Idaho Skies for this week’s event reminders and sky maps.

For Idaho Skies this is Rachel...

PAUL
...and Paul.

RACHEL
Dark skies and bright stars.

This month look for the star Betelgeuse or Alpha Orionis in the constellation of Orion the Hunter. Betelgeuse is the second brightest star in Orion, which is one of the most recognizable constellations in the winter sky. Betelgeuse is located in the upper left corner and is orangish in color. Betelgeuse and Orion are located high in the southeast on January nights after sunset.

Betelgeuse comes from the Arabic for “hand of the central one”. The central one is a female Arabic character. Feminine names in Orion the hunter are not unusual, one of the constellation’s other bright stars is named Bellatrix, which is also has a female connotation. The light you see from Betelgeuse left the star in the year 1371.

Betelgeuse (the name sounds like beetle juice) is one of the largest stars in our galaxy. If it replaced our sun, its vaporous surface would reach over half way to Jupiter, engulfing the planets Mercury, Venus, Earth, and Mars in the process. That’s 600 times larger than our sun! Betelgeuse is a giant cool red star today; but in its stellar youth was a massive white hot star. Being seven times more massive than the sun, Betelgeuse burned through its main supply of hydrogen faster than the sun. Today, deep in its core, nuclei of helium atoms are fusing into carbon and oxygen. Outside that core is a shell of fusing hydrogen. Since that helium is denser than hydrogen, the helium created by the fusion of hydrogen sinks into the star’s core where it is fused into more carbon and oxygen. The increased heat generated by star’s fusion of hydrogen and helium has puffed up its atmosphere. The expanded atmosphere is a cool red-orange color as a result. However, because of its great size, Betelgeuse over 40,000 times brighter than our sun even though its surface is cooler.

Betelgeuse is so massive that it may eventually fuse the atoms in its core all the way to iron. When it does, the star will face an energy crisis that pales to anything we’ll ever see. That’s because iron is a dead end element and it’s impossible to fuse it into heavier elements to release energy. Since stars need that energy to support their weight, they collapse when their cores contains too much iron. The inward collapse of a massive iron core squeezes subatomic protons and electrons into neutrons and an immense blast of neutrino radiation that will outpace the emission of light from the dense core of the star. Betelgeuse’s blast of neutrino radiation will arrive at earth some 643 years after the core collapses, signally that the star is beginning to exploding as a supernova. When it goes, Betelgeuse will shine as brightly as the crescent moon and be visible in broad daylight.

Transcript for December 21st to 27th

PAUL
Welcome to Idaho Skies for the fourth week of December. We’re your hosts, Paul...

RACHEL
...and Rachel.

BRING DOWN MUSIC

PAUL
The sun reaches its southernmost declination at 5:00 PM on the 21st.

RACHEL
That means it appears overhead to anyone residing at 23 degrees south latitude.

PAUL
That makes it the first day of summer in Australia and the first day of winter for us in the Northern hemisphere.

RACHEL
Ahh, just imagine, spending Christmas on an Australian beach.

PAUL
The distance between the sun and Earth has nothing to do with the seasons.

RACHEL
That’s right; the seasons are solely the result of Earth’s tilt with respect to its orbital plane around the sun.

PAUL
As a result of this tilt, the sun crosses the sky at its lowest path on the first day of winter.

RACHEL
And the hours of daylight are at their shortest length.

PAUL
The result is that the sun’s light is less intense and provides warmth for least number of hours.

RACHEL
Adding insult to injury, the night lasts it longest.

PAUL
Therefore, the ground has even more time to radiate its warmth back into the sky.

RACHEL
The combination of these three effects creates the coldest days of the year.

PAUL
However, its takes the ground and atmosphere another month to catch up to all that cold.

RACHEL
A minor meteor shower peaks on the night of December 22nd and morning of the 23rd.

PAUL
It’s the Ursid meteor shower and you can see it radiating out of the high north, near the Little Dipper or Ursa Minor.

RACHEL
Usually we don’t see more than 10 meteors per hour from this shower.

PAUL
However, it once produced an outburst of 100 meteors per hour.

RACHEL
The moon is only a day old tonight, so its light won’t interfere if you choose to watch the Ursid meteor shower.

PAUL
The 23rd presents us with the opportunity to observe a two-day old moon.

RACHEL
This is such a thin crescent moon that most people won’t chance upon it unless they know to look for it.

PAUL
So begin your search low in the southwest at around 6:15 PM.

RACHEL
You might find a pair of binoculars helpful.

PAUL
But please, please only use them after the sun has set.

RACHEL
After all these months, Mars is still visible in our night sky.

PAUL
Yep. And you can find the red planet on the 24th.

RACHEL
You first need to find the moon in the low southwest.

PAUL
Mars will be the slightly yellowish star located to the moon’s left.

RACHEL
Mars is not really red; its surface is more orange in color.

PAUL
That color comes from the oxidized iron in its soil.

RACHEL
So the surface of Mars is actually rusty.

PAUL
Because its soil doesn’t contain organic material, we actually call the soil of Mars its regolith.

RACHEL
That’s Idaho Skies for the fourth week of December. You can use your Christmas binoculars to observe a star cluster next week.

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

RACHEL
...and Rachel.

PAUL
Dark skies and bright stars.