PAUL
Welcome to Idaho Skies for the fourth week of January. We’re your hosts, Paul...
RACHEL
...and Rachel.
PAUL
Late on the 25th, you’ll find the star Regulus above the moon.
RACHEL
Regulus is the alpha star of Leo the Lion and it has a faintly yellow-orange tint to it.
PAUL
However, it’s actually two pairs of stars orbiting each other.
RACHEL
Two pairs?
PAUL
That’s right, four stars in total.
RACHEL
Hey, Regulus is also 79 light years away.
PAUL
So if you know someone who is 79 years old, then Regulus is his or her birthday star this year.
RACHEL
The primary star of the Regulus star system is 3.5 times more massive than the sun.
PAUL
What’s really weird about it is that it spins once on its axis in just 16 hours.
RACHEL
When you compare that to the sun, which rotates on its axis once per month, you’ll realize just how much faster this massive star spins on its axis.
PAUL
In fact, if it rotated 2.5 hours faster, the star would fling itself apart.
RACHEL
Because of its rapid spin, Regulus is significantly flattened at its poles and bulges at its equator.
PAUL
This makes the poles of the star five times brighter than its equator.
RACHEL
You’ll find two nice binocular objects paired up late on the night of the 27th.
PAUL
They’re the moon and Jupiter.
RACHEL
The pair is only 3.5 degrees apart, or close enough together to seen at the same time in a pair of binoculars.
PAUL
Jupiter, which appears as the bright star just above the moon, will have a slightly creamy color.
RACHEL
And it won’t twinkle like the other stars.
PAUL
Point your binoculars at Jupiter and you’ll see two or three of its largest satellites forming a line with Jupiter.
RACHEL
The satellite at the bottom of the line is Callisto, a world larger than our moon.
PAUL
The next one up and very close to Jupiter is Io.
RACHEL
It’s a world of frequent volcanic eruptions.
PAUL
In fact, there are more ongoing eruptions on Io than on Earth.
RACHEL
The last satellite, which is located above Jupiter, is named Ganymede.
PAUL
Ganymede, like Callisto, is a large satellite and also very icy.
RACHEL
What about that star appearing to the lower right of the moon on the morning of the 30th?
PAUL
Why that’s Spica, the brightest star of Virgo the Maiden.
RACHEL
Spica and the moon will be very close together on the morning of the 30th.
PAUL
The pair is so close that you can see both together at the same time in binoculars.
RACHEL
It’s sad that the rest of Virgo isn’t as eye catching as its brightest star.
PAUL
But hey, this is still a good time to learn how to identify this star.
RACHEL
That’s Idaho Skies for the fourth week of January. The moon passes very close to Mars and a double star 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.
Monday, January 25, 2016
Tuesday, January 19, 2016
Transcript for January 17 - 23
RACHEL
Welcome to Idaho Skies for the third week of January. We’re your hosts, Rachel...
PAUL
...and Paul.
RACHEL
The moon forms a triangle of astronomical objects with the Pleiades and the Hyades star clusters on the night of the 18th.
PAUL
All three of these astronomical objects are great targets for your binoculars.
RACHEL
The moon will be a bit on the bright side and will show mostly lunar seas in your binoculars.
PAUL
But the Pleiades and Hyades will show a multitude of stars that are invisible to the naked eye.
RACHEL
Whoa, the moon covers up the brightest star in Taurus the Bull on the 19th.
PAUL
Astronomers call this event an occultation and it’s with the star Aldebaran.
RACHEL
The occultation begins at 6:17 PM when the moon covers up Aldebaran.
PAUL
Unfortunately, it will still be light outside, so this part of the occultation is not observable.
RACHEL
However, at 7:28 PM when the moon uncovers Aldebaran, it will be quite dark outside.
PAUL
To watch the reappearance of Aldebaran, look along the right edge of the moon with your binoculars at 7:25.
RACHEL
Aldebaran will suddenly pop into view a few minutes later and it will just a bit above, half way up the moon’s limb.
PAUL
The rapidity of Aldebaran’s reappearance is evidence that the moon has no atmosphere.
RACHEL
That’s because even a modest lunar atmosphere would make Aldebaran’s reappearance more gradual.
PAUL
By observing an occultation from multiple locations, astronomers can determine information regarding the size, shape, and atmosphere of asteroids, moons, and planets in our solar system.
RACHEL
Orion the Hunter is an easy constellation to find, but it’s even easier on the evening of the 20th.
PAUL
That’s because the moon appears just above Orion that night.
RACHEL
Orion will be the tall rectangle of stars below the moon.
PAUL
Once you locate Orion, look for his belt.
RACHEL
Which is a row of three stars across Orion’s waist.
PAUL
Once you have located his belt, look below the middle star of the belt.
RACHEL
In binoculars, you’ll see what appears to be a fuzzy star below his belt.
PAUL
This is the Orion Nebula.
RACHEL
The nebula is easy to see with binoculars.
PAUL
But it’s even more spectacular through a telescope.
RACHEL
Through a telescope, it takes on a swirled pattern of pale greenish light.
PAUL
The very attractive Beehive star cluster appears just 8 degrees away from the moon on the night of the 23rd.
RACHEL
To find it, point your binoculars at the moon and then shift your view to the left.
PAUL
Shortly after the moon exits the right side of your binocular’s field of view, the star cluster enters the left side.
RACHEL
Since the average pair of binoculars has a field of view of 5 degrees, you don’t have to shift the binoculars very far before the Beehive appears.
PAUL
In binoculars, the Beehive appears as a small grouping of tightly bound stars.
RACHEL
And it will have a strong resemblance to a swarm of bees around their hive
PAUL
That’s Idaho Skies for the third week of January. The moon will help you locate the planet Jupiter 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.
Welcome to Idaho Skies for the third week of January. We’re your hosts, Rachel...
PAUL
...and Paul.
RACHEL
The moon forms a triangle of astronomical objects with the Pleiades and the Hyades star clusters on the night of the 18th.
PAUL
All three of these astronomical objects are great targets for your binoculars.
RACHEL
The moon will be a bit on the bright side and will show mostly lunar seas in your binoculars.
PAUL
But the Pleiades and Hyades will show a multitude of stars that are invisible to the naked eye.
RACHEL
Whoa, the moon covers up the brightest star in Taurus the Bull on the 19th.
PAUL
Astronomers call this event an occultation and it’s with the star Aldebaran.
RACHEL
The occultation begins at 6:17 PM when the moon covers up Aldebaran.
PAUL
Unfortunately, it will still be light outside, so this part of the occultation is not observable.
RACHEL
However, at 7:28 PM when the moon uncovers Aldebaran, it will be quite dark outside.
PAUL
To watch the reappearance of Aldebaran, look along the right edge of the moon with your binoculars at 7:25.
RACHEL
Aldebaran will suddenly pop into view a few minutes later and it will just a bit above, half way up the moon’s limb.
PAUL
The rapidity of Aldebaran’s reappearance is evidence that the moon has no atmosphere.
RACHEL
That’s because even a modest lunar atmosphere would make Aldebaran’s reappearance more gradual.
PAUL
By observing an occultation from multiple locations, astronomers can determine information regarding the size, shape, and atmosphere of asteroids, moons, and planets in our solar system.
RACHEL
Orion the Hunter is an easy constellation to find, but it’s even easier on the evening of the 20th.
PAUL
That’s because the moon appears just above Orion that night.
RACHEL
Orion will be the tall rectangle of stars below the moon.
PAUL
Once you locate Orion, look for his belt.
RACHEL
Which is a row of three stars across Orion’s waist.
PAUL
Once you have located his belt, look below the middle star of the belt.
RACHEL
In binoculars, you’ll see what appears to be a fuzzy star below his belt.
PAUL
This is the Orion Nebula.
RACHEL
The nebula is easy to see with binoculars.
PAUL
But it’s even more spectacular through a telescope.
RACHEL
Through a telescope, it takes on a swirled pattern of pale greenish light.
PAUL
The very attractive Beehive star cluster appears just 8 degrees away from the moon on the night of the 23rd.
RACHEL
To find it, point your binoculars at the moon and then shift your view to the left.
PAUL
Shortly after the moon exits the right side of your binocular’s field of view, the star cluster enters the left side.
RACHEL
Since the average pair of binoculars has a field of view of 5 degrees, you don’t have to shift the binoculars very far before the Beehive appears.
PAUL
In binoculars, the Beehive appears as a small grouping of tightly bound stars.
RACHEL
And it will have a strong resemblance to a swarm of bees around their hive
PAUL
That’s Idaho Skies for the third week of January. The moon will help you locate the planet Jupiter 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.
See Five Planets at One Time
Here's a link to Sky and Telescope and their article on seeing the five visible planets at one time.
http://www.skyandtelescope.com/astronomy-news/observing-news/get-up-early-see-five-planets-at-once-01182015/
http://www.skyandtelescope.com/astronomy-news/observing-news/get-up-early-see-five-planets-at-once-01182015/
Monday, January 11, 2016
Transcript for January 10 - 16
PAUL
Welcome to Idaho Skies for the second week of January. We’re your hosts, Paul...
RACHEL
...and Rachel.
PAUL
The moon was new on the 9th.
RACHEL
A new moon means the moon is passing between Earth and the sun.
PAUL
That happens every 29 or 30 days, or once every lunar orbit.
RACHEL
The moon is dark at new moon, but not because the "dark side" of the moon is turned toward us.
PAUL
In fact, we always see the same face of the moon.
RACHEL
The reason the moon is dark at new is that the portion of the moon in night also happens to be the half facing Earth.
PAUL
We only see one half of the moon because its period of rotation, which is also the length of its day, is the same as its orbit around Earth.
RACHEL
The same thing would happen between Earth and the sun if our day were 365 days long rather than 24 hours long.
PAUL
After its birth, the moon probably rotated much faster on its axis.
RACHEL
However, because of it closeness to us, Earth’s gravity slowed down the moon’s rotation until now it rotates once every revolution around Earth.
PAUL
Astronomers call the moon tidally locked with Earth.
RACHEL
This is the current situation between Pluto and its largest moon, Chiron.
PAUL
And probably with some of the hot Jupiter exoplanets that astronomers have discovered outside our solar system.
RACHEL
In time, the moon may be able to slow down Earth’s spin until both are tidally locked together.
PAUL
Then only one half of Earth will be able to see half of the moon.
RACHEL
Sadly, because of the tilt of the moon’s orbit around Earth, the new moon passed above the sun from Earth’s perspective.
PAUL
Robbing Idaho of its chance to see a solar eclipse this month.
RACHEL
The moon reappears low in the south-southwest on the evening of the 11th.
PAUL
The moon will be two days old then, so it will be very thin.
RACHEL
In another day or two, you should be able to see earthshine on the dark portion of the moon.
PAUL
Binoculars give a better view of earthshine than the eye alone.
RACHEL
Keep observing the moon through binoculars, as it will look pretty neat for the next four or five days.
PAUL
That’s because you’ll see lots of craters and mountains along the lunar terminator.
RACHEL
The terminator is the moon’s boundary between day and night.
PAUL
At the terminator, shadows bring out the greatest lunar detail.
RACHEL
The view is even better when the moon’s seven days old and the terminator faces directly towards Earth
PAUL
That makes the lunar shadows appear especially long.
RACHEL
And that extended length readily emphasizes small changes in the lunar terrain.
PAUL
Because of the moon’s small size and slow rotation, the terminator travels around the moon at just under 10 miles per hour.
RACHEL
Therefore, it would be easy for a runner to keep up with the movement of the terminator.
PAUL
That’s Idaho Skies for the second week of January. Next week, Idahoan’s get to observe a lunar occultation.
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.
Welcome to Idaho Skies for the second week of January. We’re your hosts, Paul...
RACHEL
...and Rachel.
PAUL
The moon was new on the 9th.
RACHEL
A new moon means the moon is passing between Earth and the sun.
PAUL
That happens every 29 or 30 days, or once every lunar orbit.
RACHEL
The moon is dark at new moon, but not because the "dark side" of the moon is turned toward us.
PAUL
In fact, we always see the same face of the moon.
RACHEL
The reason the moon is dark at new is that the portion of the moon in night also happens to be the half facing Earth.
PAUL
We only see one half of the moon because its period of rotation, which is also the length of its day, is the same as its orbit around Earth.
RACHEL
The same thing would happen between Earth and the sun if our day were 365 days long rather than 24 hours long.
PAUL
After its birth, the moon probably rotated much faster on its axis.
RACHEL
However, because of it closeness to us, Earth’s gravity slowed down the moon’s rotation until now it rotates once every revolution around Earth.
PAUL
Astronomers call the moon tidally locked with Earth.
RACHEL
This is the current situation between Pluto and its largest moon, Chiron.
PAUL
And probably with some of the hot Jupiter exoplanets that astronomers have discovered outside our solar system.
RACHEL
In time, the moon may be able to slow down Earth’s spin until both are tidally locked together.
PAUL
Then only one half of Earth will be able to see half of the moon.
RACHEL
Sadly, because of the tilt of the moon’s orbit around Earth, the new moon passed above the sun from Earth’s perspective.
PAUL
Robbing Idaho of its chance to see a solar eclipse this month.
RACHEL
The moon reappears low in the south-southwest on the evening of the 11th.
PAUL
The moon will be two days old then, so it will be very thin.
RACHEL
In another day or two, you should be able to see earthshine on the dark portion of the moon.
PAUL
Binoculars give a better view of earthshine than the eye alone.
RACHEL
Keep observing the moon through binoculars, as it will look pretty neat for the next four or five days.
PAUL
That’s because you’ll see lots of craters and mountains along the lunar terminator.
RACHEL
The terminator is the moon’s boundary between day and night.
PAUL
At the terminator, shadows bring out the greatest lunar detail.
RACHEL
The view is even better when the moon’s seven days old and the terminator faces directly towards Earth
PAUL
That makes the lunar shadows appear especially long.
RACHEL
And that extended length readily emphasizes small changes in the lunar terrain.
PAUL
Because of the moon’s small size and slow rotation, the terminator travels around the moon at just under 10 miles per hour.
RACHEL
Therefore, it would be easy for a runner to keep up with the movement of the terminator.
PAUL
That’s Idaho Skies for the second week of January. Next week, Idahoan’s get to observe a lunar occultation.
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.
Monday, January 4, 2016
Transcripts for Janaury 3 - 9
RACHEL
Welcome to Idaho Skies for the first week of January. We’re your hosts, Rachel...
PAUL
...and Paul.
RACHEL
Hey, are you looking for Mars?
PAUL
That’s good, because it’s easy to find on the morning of the 3rd.
RACHEL
Mars will be the orangish star below the moon that morning.
PAUL
And it will be difficult to confuse with Spica, which will be the whitish star to the right of the moon.
RACHEL
Some of our listeners know that Spica is the brightest star of Virgo the Maiden.
PAUL
But did you know it was 260 light years away?
RACHEL
Let’s compare that to the distance to Mars.
PAUL
Sure, Mars is currently located on the other side of the solar system.
RACHEL
That means it’s a mere 153 million miles away.
PAUL
Or about 13 light minutes away.
RACHEL
So this makes Spica over 10 million times farther away from Earth than Mars.
PAUL
Now for some astronomical news closer to home.
RACHEL
The first significant meteor shower of the year occurs on the night of the 3rd and the morning of the 4th.
PAUL
The Quadrantid meteor shower is an above average shower that produces upwards of 40 meteors per hour.
RACHEL
Meteors in this shower will originate from the low north-northeast
PAUL
There’s one problem however and that’s the moon.
RACHEL
Its third quarter, so once it rises, its light will make the fainter meteors difficult to see.
PAUL
Fortunately for our listeners, the moon doesn’t rise until 3:00 AM.
RACHEL
That leaves everyone with 8 hours of meteor viewing.
PAUL
So dress warmly, relax in a lawn chair, and look skyward while enjoying the warm beverage of your choice.
RACHEL
Venus and Saturn are currently approaching each other, from Earth’s perspective.
PAUL
You’ll see them as a bright white star and its fainter creamy white companion in the low east before sunrise.
RACHEL
Even better, the moon joins the pair on the morning of the 6th.
PAUL
Venus will be the brightest star to the lower left of the moon.
RACHEL
And Saturn will be the fainter star further below Venus.
PAUL
Hey, what’s that orangish star directly below the moon?
RACHEL
Why it’s Antares, the brightest star in Scorpius the Scorpion.
PAUL
To see this fine grouping, you’ll want to look in the low southeast at 7:00 AM on the 6th.
RACHEL
The moon isn’t quite finished with Venus and Saturn.
PAUL
That’s right. On the morning of the 7th, you’ll find the crescent moon below Saturn and Venus.
RACHEL
What makes this grouping so special is that the moon is 2 days from new.
PAUL
And when the moon is that close to new, it’s a very thin crescent.
RACHEL
So get your binoculars out and see if you can detect any of its nearly edge-on craters.
PAUL
On the morning of the 9th, Venus and Saturn will be in conjunction.
RACHEL
In astronomy, conjunction occurs when two objects are separated from one another in only the north-south direction.
PAUL
Think of this as two objects having the same longitude on Earth.
RACHEL
Except in astronomy, a line of longitude goes by the name of right ascension.
PAUL
During the conjunction, Venus and Saturn are only ½ of a degree apart from one another.
RACHEL
Which is the apparent diameter of the moon.
PAUL
Be sure to go out between 6:00 and 7:00 AM on the 9th to see the conjunction between Venus and Saturn.
RACHEL
That’s Idaho Skies for the first week of January. We’ll give you some news regarding the new moon 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.
Welcome to Idaho Skies for the first week of January. We’re your hosts, Rachel...
PAUL
...and Paul.
RACHEL
Hey, are you looking for Mars?
PAUL
That’s good, because it’s easy to find on the morning of the 3rd.
RACHEL
Mars will be the orangish star below the moon that morning.
PAUL
And it will be difficult to confuse with Spica, which will be the whitish star to the right of the moon.
RACHEL
Some of our listeners know that Spica is the brightest star of Virgo the Maiden.
PAUL
But did you know it was 260 light years away?
RACHEL
Let’s compare that to the distance to Mars.
PAUL
Sure, Mars is currently located on the other side of the solar system.
RACHEL
That means it’s a mere 153 million miles away.
PAUL
Or about 13 light minutes away.
RACHEL
So this makes Spica over 10 million times farther away from Earth than Mars.
PAUL
Now for some astronomical news closer to home.
RACHEL
The first significant meteor shower of the year occurs on the night of the 3rd and the morning of the 4th.
PAUL
The Quadrantid meteor shower is an above average shower that produces upwards of 40 meteors per hour.
RACHEL
Meteors in this shower will originate from the low north-northeast
PAUL
There’s one problem however and that’s the moon.
RACHEL
Its third quarter, so once it rises, its light will make the fainter meteors difficult to see.
PAUL
Fortunately for our listeners, the moon doesn’t rise until 3:00 AM.
RACHEL
That leaves everyone with 8 hours of meteor viewing.
PAUL
So dress warmly, relax in a lawn chair, and look skyward while enjoying the warm beverage of your choice.
RACHEL
Venus and Saturn are currently approaching each other, from Earth’s perspective.
PAUL
You’ll see them as a bright white star and its fainter creamy white companion in the low east before sunrise.
RACHEL
Even better, the moon joins the pair on the morning of the 6th.
PAUL
Venus will be the brightest star to the lower left of the moon.
RACHEL
And Saturn will be the fainter star further below Venus.
PAUL
Hey, what’s that orangish star directly below the moon?
RACHEL
Why it’s Antares, the brightest star in Scorpius the Scorpion.
PAUL
To see this fine grouping, you’ll want to look in the low southeast at 7:00 AM on the 6th.
RACHEL
The moon isn’t quite finished with Venus and Saturn.
PAUL
That’s right. On the morning of the 7th, you’ll find the crescent moon below Saturn and Venus.
RACHEL
What makes this grouping so special is that the moon is 2 days from new.
PAUL
And when the moon is that close to new, it’s a very thin crescent.
RACHEL
So get your binoculars out and see if you can detect any of its nearly edge-on craters.
PAUL
On the morning of the 9th, Venus and Saturn will be in conjunction.
RACHEL
In astronomy, conjunction occurs when two objects are separated from one another in only the north-south direction.
PAUL
Think of this as two objects having the same longitude on Earth.
RACHEL
Except in astronomy, a line of longitude goes by the name of right ascension.
PAUL
During the conjunction, Venus and Saturn are only ½ of a degree apart from one another.
RACHEL
Which is the apparent diameter of the moon.
PAUL
Be sure to go out between 6:00 and 7:00 AM on the 9th to see the conjunction between Venus and Saturn.
RACHEL
That’s Idaho Skies for the first week of January. We’ll give you some news regarding the new moon 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.
Alcyone, of the Pleiades, is January's Star
This month look for the star Alcyone, the brightest star in the open cluster, the Pleiades. The Japanese name the cluster, Subaru, so look carefully at the next Subaru you see. The symbol on the car is a stylized diagram of the Pleiades star cluster. The Pleiades goes by the names of M-45 and the Seven Sisters (although most people only see six stars without optical aid). The seven sisters were daughters of the titan, Atlas and his wife, Pleione. The names of the six stars most people see, in order of brightness, are Alcyone, Electra, Maia, Atlas, Merope, and Taygeta. The next three fainter stars are named after the their mother and the two remaining sisters, Pleione, Celaeno, and Asterope The first known mention of the Pleiades was around 1,000 BC by the Greek writer Hesiod.
In 10X50 binoculars, the brightest portion of the Pleiades occupies about 1/5th of the field of view. When you include the fainter surrounding stars, the Pleiades occupies closer to 1/4th of the field of view. In moderately light polluted skies, I could easily see 20 stars though my binoculars and Alcyone is the brightest Pleiad and located is the center of the star cluster.
The Pleiades are 440 light years away. Therefore, the Pleiades you see tonight existed back in 1575. They formed from the same cloud of dust and gas about 100 million years ago. In time, the stars of the Pleiades will drift a part, as their combined gravity is too weak to hold the cluster together. In long duration exposures, a blue cloud of dust appears surrounding the stars. The stars and bright blue-white frosting makes the Pleiades look like some fantastic piece of jewelry. The cloud however, is not what remains of the dust and gas from which the Pleiades formed. It happens to be a separate cloud that the cluster is currently drifting through.
The Pleiades and Alcyone are visible high in the east on December nights.
In 10X50 binoculars, the brightest portion of the Pleiades occupies about 1/5th of the field of view. When you include the fainter surrounding stars, the Pleiades occupies closer to 1/4th of the field of view. In moderately light polluted skies, I could easily see 20 stars though my binoculars and Alcyone is the brightest Pleiad and located is the center of the star cluster.
The Pleiades are 440 light years away. Therefore, the Pleiades you see tonight existed back in 1575. They formed from the same cloud of dust and gas about 100 million years ago. In time, the stars of the Pleiades will drift a part, as their combined gravity is too weak to hold the cluster together. In long duration exposures, a blue cloud of dust appears surrounding the stars. The stars and bright blue-white frosting makes the Pleiades look like some fantastic piece of jewelry. The cloud however, is not what remains of the dust and gas from which the Pleiades formed. It happens to be a separate cloud that the cluster is currently drifting through.
The Pleiades and Alcyone are visible high in the east on December nights.
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