RACHEL
Welcome to Idaho Skies for the fifth week of February. We’re your hosts, Rachel...
PAUL
...and Paul.
RACHEL
Zubenelgenubi is a star that’s easy to split into two separate stars through binoculars.
PAUL
Astronomers call stars like this double stars.
RACHEL
Binoculars show Zubenelgenubi as two separate stars because the separation between them is wide at 4 arc seconds.
PAUL
Can you describe an arc second?
RACHEL
Sure. An arc second is 1/60th of a degree.
PAUL
So the separation between the two stars making up Zubenelgenubi is 4/60ths of a degree, or 1/15th.
RACHEL
That’s right. And that’s large enough of an angle that some people can split Zubenelgenubi into two stars with just their eyes.
PAUL
The problem is not splitting Zubenelgenubi into two stars, but finding it in the first place.
RACHEL
The reason it can be difficult to find is that it’s located in a rather blank portion of the sky.
PAUL
That’s where the moon comes in handy.
RACHEL
Zubenelgenubi will be the star below the moon on the morning of the 28th.
PAUL
Get your binoculars out and take a peek at Zubenelgenubi and then see if you can split it into two stars without your binoculars.
RACHEL
An even more famous double star is Mizar and Alcor.
PAUL
This pair of stars is located in the bend of the Big Dipper’s handle.
RACHEL
And the timing is perfect because you’ll find Mizar and Alcor in the high north on the 28th.
PAUL
The separation between the brighter Mizar and fainter Alcor is 14 arc seconds.
RACHEL
Or half the apparent diameter of the moon.
PAUL
This means everyone with good vision can resolve Mizar and Alcor as separate stars.
RACHEL
Rumor has it that ancient people used the pair as a vision test.
PAUL
So take a few minutes of your time after midnight of the 28th to test your vision on these two double stars.
RACHEL
The Angry Red Planet...
PAUL
...that’s Mars...
RACHEL
...is below the moon on the morning of the 29th.
PAUL
Do you remember that the moon passed close to Mars back on the 1st?
RACHEL
Back then, Mars was located just above Zubenelgenubi.
PAUL
Now, a month later, Mars has moved 12 degrees further east.
RACHEL
Look in the low south at 5:00 AM for the moon and you’ll see orangish Mars four degrees below the moon.
PAUL
A separation of four degrees means you can see both in a pair of binoculars.
RACHEL
However, you’ll need to place the moon near the very top of the field of view.
PAUL
Earth is approaching closer to Mars.
RACHEL
This means Earth and Mars will be at their closest in May.
PAUL
So soon, good telescopes will begin showing surface features of Mars.
RACHEL
Features like Syrtis Major and Hellas.
PAUL
That’s Idaho Skies for the last week of February. Next week the moon helps locate two planets.
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.
Monday, February 29, 2016
Monday, February 22, 2016
Idaho Skies Transcript for February 21st to 27th
PAUL
Welcome to Idaho Skies for the fourth week of February. We’re your hosts, Paul...
RACHEL
...and Rachel.
PAUL
After it gets dark on the 21st, look for a yellowish-orange star to the left of the moon.
RACHEL
This is Regulus, the brightest star of Leo the Lion.
PAUL
Because of the yellowish-orange tint in the star and it location in the constellation, Regulus represents the heart of the lion.
RACHEL
You’ll find the head and mane of Leo easy to identify.
PAUL
The back of his head and mane are outlined by the backwards question mark of stars above Regulus.
RACHEL
It takes the moon two days to traverse Leo.
PAUL
And by then, the moon will have reached its next destination, Jupiter.
RACHEL
Jupiter appears as a bright creamy-white star 2.5 degrees above the moon on the evening of the 23rd.
PAUL
Since the moon is ½ degrees across, Jupiter is five lunar diameters above the moon.
RACHEL
However, it may appear even closer than that to the moon.
PAUL
The reason why is that our eyes and brain makes the moon appear even larger when it’s near the horizon.
RACHEL
This is called the Moon Illusion.
PAUL
You can test this illusion by comparing the size of your thumb nail to the apparent size of the moon when it first rises and then several hours later.
RACHEL
So pretend to be hitch-hiking and extend your arm and thumb.
PAUL
Then compare the size of your thumb to the recently risen moon.
RACHEL
The moon will seem larger to your mind because it has just risen.
PAUL
However, your thumbnail measurement will show the moon’s about equal to half the width of your thumbnail.
RACHEL
Now repeat this experiment an hour or two later.
PAUL
Because the moon is no where near the horizon, it should appear smaller than it did an hour or two ago.
RACHEL
But surprise, you’ll find it’s still half as wide as your thumb nail when your arm is fully extended.
PAUL
So both times the moon was the same size.
RACHEL
However, to your mind, the newly risen moon appeared significantly larger.
PAUL
There’s no consensus on why the moon near the horizon appears larger than the moon when it’s overhead.
RACHEL
However, it may be due to the way our brain interprets how far away the sky is.
PAUL
After performing this experiment, get your binoculars out and take a peek at Jupiter.
RACHEL
Through binoculars, you’ll at least one of Jupiter’s satellites, Callisto.
PAUL
It will appear as the star located below Jupiter.
RACHEL
If you steady your binoculars, like on a fence post, you might also see another satellite, Europa.
PAUL
Europa will be another faint star, but located above Jupiter.
RACHEL
Europa will be more difficult to see because it’s closer to the Jupiter than Callisto.
PAUL
Jupiter’s other two satellites are Io and Ganymede.
RACHEL
...which are located below Jupiter, like Callisto.
PAUL
But they’re too close to the glare of Jupiter to see through binoculars.
RACHEL
A small telescope or spotting scope however, has enough magnification to see all four satellites.
PAUL
But watch out, through a telescope, the view will be upside down compared to what you will see in binoculars.
RACHEL
That’s Idaho Skies for the fourth week of February. Most stars have companion stars and we can see some of them with modest optical aid. Learn more 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 fourth week of February. We’re your hosts, Paul...
RACHEL
...and Rachel.
PAUL
After it gets dark on the 21st, look for a yellowish-orange star to the left of the moon.
RACHEL
This is Regulus, the brightest star of Leo the Lion.
PAUL
Because of the yellowish-orange tint in the star and it location in the constellation, Regulus represents the heart of the lion.
RACHEL
You’ll find the head and mane of Leo easy to identify.
PAUL
The back of his head and mane are outlined by the backwards question mark of stars above Regulus.
RACHEL
It takes the moon two days to traverse Leo.
PAUL
And by then, the moon will have reached its next destination, Jupiter.
RACHEL
Jupiter appears as a bright creamy-white star 2.5 degrees above the moon on the evening of the 23rd.
PAUL
Since the moon is ½ degrees across, Jupiter is five lunar diameters above the moon.
RACHEL
However, it may appear even closer than that to the moon.
PAUL
The reason why is that our eyes and brain makes the moon appear even larger when it’s near the horizon.
RACHEL
This is called the Moon Illusion.
PAUL
You can test this illusion by comparing the size of your thumb nail to the apparent size of the moon when it first rises and then several hours later.
RACHEL
So pretend to be hitch-hiking and extend your arm and thumb.
PAUL
Then compare the size of your thumb to the recently risen moon.
RACHEL
The moon will seem larger to your mind because it has just risen.
PAUL
However, your thumbnail measurement will show the moon’s about equal to half the width of your thumbnail.
RACHEL
Now repeat this experiment an hour or two later.
PAUL
Because the moon is no where near the horizon, it should appear smaller than it did an hour or two ago.
RACHEL
But surprise, you’ll find it’s still half as wide as your thumb nail when your arm is fully extended.
PAUL
So both times the moon was the same size.
RACHEL
However, to your mind, the newly risen moon appeared significantly larger.
PAUL
There’s no consensus on why the moon near the horizon appears larger than the moon when it’s overhead.
RACHEL
However, it may be due to the way our brain interprets how far away the sky is.
PAUL
After performing this experiment, get your binoculars out and take a peek at Jupiter.
RACHEL
Through binoculars, you’ll at least one of Jupiter’s satellites, Callisto.
PAUL
It will appear as the star located below Jupiter.
RACHEL
If you steady your binoculars, like on a fence post, you might also see another satellite, Europa.
PAUL
Europa will be another faint star, but located above Jupiter.
RACHEL
Europa will be more difficult to see because it’s closer to the Jupiter than Callisto.
PAUL
Jupiter’s other two satellites are Io and Ganymede.
RACHEL
...which are located below Jupiter, like Callisto.
PAUL
But they’re too close to the glare of Jupiter to see through binoculars.
RACHEL
A small telescope or spotting scope however, has enough magnification to see all four satellites.
PAUL
But watch out, through a telescope, the view will be upside down compared to what you will see in binoculars.
RACHEL
That’s Idaho Skies for the fourth week of February. Most stars have companion stars and we can see some of them with modest optical aid. Learn more 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.
Tuesday, February 16, 2016
Transcript: 14 - 20 February
RACHEL
Welcome to Idaho Skies for the third week of February. We’re your hosts, Rachel...
PAUL
...and Paul.
RACHEL
The moon reaches the first quarter phase on the 15th.
PAUL
That’s the same day it passes through the Hyades star cluster.
RACHEL
But wait, there’s more.
PAUL
The moon is also approaching the brightest star in the Hyades, Aldebaran.
RACHEL
Then starting just after 2:00 AM you can watch Aldebaran skim the north polar region of the moon.
PAUL
Even your binoculars are enough to observe this occultation.
RACHEL
If you observe Aldebaran winking out and then reappearing soon after if disappears, it’s because the star is passing behind tall mountains or crater rims.
PAUL
The occultation ends at 2:25 AM on the 16th.
RACHEL
Meaning you’ll have between 2:00 to 2:25 AM to watch Aldebaran skim the northern polar region of the moon.
PAUL
The next evening, the 16th, the moon passes through Taurus the Bull and above Orion the Hunter.
RACHEL
Four very bright stars make up the corners of the rectangular body of Orion.
PAUL
Clockwise, starting from top left, the stars are named Betelgeuse...
RACHEL
...Bellatrix...
PAUL
...Rigel...
RACHEL
...and Saph.
PAUL
The moon continues in its restless ways.
RACHEL
It leaves Orion on the 16th and enters Gemini on the 18th.
PAUL
That night, the moon passes below the twins, specifically, Pollux.
RACHEL
Pollux was the mortal half of the Gemini Twins and his star is slightly brighter than his brother, Castor, which is above Pollux.
PAUL
Finally, this week, the moon takes us on a trip to find an easy to see star cluster.
RACHEL
On the night of the 20th, the moon is below the Beehive star cluster.
PAUL
The Beehive is one of the closest star clusters at a mere 577 light years away.
RACHEL
Astronomers have determined that the cluster contains over 1,000 members.
PAUL
...although only some four dozen are observable in binoculars.
RACHEL
Because of its small size and the relative brightness of its members, it’s a very attractive sight through binoculars or small telescope.
PAUL
Did you know that you can see the Beehive without optical aid?
RACHEL
In dark skies, it appears as a small fuzzy patch.
PAUL
This is why the ancients knew about it over 2,000 years ago.
RACHEL
Well, did you know they also used it to predict the weather?
PAUL
How do you the predict weather using a star cluster?
RACHEL
It’s supposed to be a sign of approaching rain if you can’t see this fuzzy cluster.
PAUL
Why would this be true?
RACHEL
Perhaps because rain is sometimes preceded by high altitude cirrus clouds.
PAUL
And high altitude cirrus clouds will block the light of a fuzzy cluster like the Beehive?
RACHEL
That’s right.
PAUL
That’s Idaho Skies for the third week of February. Have you heard about the Moon Illusion? We’ll explain it 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 February. We’re your hosts, Rachel...
PAUL
...and Paul.
RACHEL
The moon reaches the first quarter phase on the 15th.
PAUL
That’s the same day it passes through the Hyades star cluster.
RACHEL
But wait, there’s more.
PAUL
The moon is also approaching the brightest star in the Hyades, Aldebaran.
RACHEL
Then starting just after 2:00 AM you can watch Aldebaran skim the north polar region of the moon.
PAUL
Even your binoculars are enough to observe this occultation.
RACHEL
If you observe Aldebaran winking out and then reappearing soon after if disappears, it’s because the star is passing behind tall mountains or crater rims.
PAUL
The occultation ends at 2:25 AM on the 16th.
RACHEL
Meaning you’ll have between 2:00 to 2:25 AM to watch Aldebaran skim the northern polar region of the moon.
PAUL
The next evening, the 16th, the moon passes through Taurus the Bull and above Orion the Hunter.
RACHEL
Four very bright stars make up the corners of the rectangular body of Orion.
PAUL
Clockwise, starting from top left, the stars are named Betelgeuse...
RACHEL
...Bellatrix...
PAUL
...Rigel...
RACHEL
...and Saph.
PAUL
The moon continues in its restless ways.
RACHEL
It leaves Orion on the 16th and enters Gemini on the 18th.
PAUL
That night, the moon passes below the twins, specifically, Pollux.
RACHEL
Pollux was the mortal half of the Gemini Twins and his star is slightly brighter than his brother, Castor, which is above Pollux.
PAUL
Finally, this week, the moon takes us on a trip to find an easy to see star cluster.
RACHEL
On the night of the 20th, the moon is below the Beehive star cluster.
PAUL
The Beehive is one of the closest star clusters at a mere 577 light years away.
RACHEL
Astronomers have determined that the cluster contains over 1,000 members.
PAUL
...although only some four dozen are observable in binoculars.
RACHEL
Because of its small size and the relative brightness of its members, it’s a very attractive sight through binoculars or small telescope.
PAUL
Did you know that you can see the Beehive without optical aid?
RACHEL
In dark skies, it appears as a small fuzzy patch.
PAUL
This is why the ancients knew about it over 2,000 years ago.
RACHEL
Well, did you know they also used it to predict the weather?
PAUL
How do you the predict weather using a star cluster?
RACHEL
It’s supposed to be a sign of approaching rain if you can’t see this fuzzy cluster.
PAUL
Why would this be true?
RACHEL
Perhaps because rain is sometimes preceded by high altitude cirrus clouds.
PAUL
And high altitude cirrus clouds will block the light of a fuzzy cluster like the Beehive?
RACHEL
That’s right.
PAUL
That’s Idaho Skies for the third week of February. Have you heard about the Moon Illusion? We’ll explain it 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.
Monday, February 8, 2016
Transcript for February 7 - 13
PAUL
Welcome to Idaho Skies for the second week of February. We’re your hosts, Paul...
RACHEL
...and Rachel.
PAUL
The moon is new on the 8th.
RACHEL
So it reappears in the west two days later.
PAUL
Starting the 10th and for the next couple of nights, look for earthshine illuminating the dark portion of the moon.
RACHEL
And remember, earthshine is sunlight, but reflected by Earth.
PAUL
How is it possible for Earth to reflect so much towards the moon?
RACHEL
It’s because of Earth’s albedo and size.
PAUL
Explain albedo.
RACHEL
Sure, albedo is the astronomical term for reflectivity.
PAUL
And an albedo of zero is a perfect absorber of light and totally non-reflective.
RACHEL
While an albedo of 1 is perfectly reflective.
PAUL
So where does the moon’s albedo lie?
RACHEL
The moon’s albedo is 0.12
PAUL
Which is another way of saying the moon only reflects 12% of the sunlight incident on it.
RACHEL
That make the moon’s surface about as dark as an asphalt parking lot.
PAUL
And that’s on average.
RACHEL
Right, the lunar seas are darker and less reflective while the lunar highlands are just the opposite.
PAUL
So what about the Earth?
RACHEL
Earth’s albedo is 0.30.
PAUL
Most of that comes from its clouds and ice caps.
RACHEL
That’s correct; the oceans are darker.
PAUL
On average then, Earth is 2.5 times brighter than the moon.
RACHEL
So we can see that Earth is more reflective than the moon, what about their relative sizes?
PAUL
The moon’s diameter is 2,100 miles.
RACHEL
That small?
PAUL
Yep. The United States would wrap 50% of the way around the moon.
RACHEL
And I remember Earth is just about 7,900 miles in diameter.
PAUL
Which means Earth has a diameter nearly four times larger than the moon.
RACHEL
And that means about 14 times more surface area to reflect sunlight.
PAUL
Combining the 14 times larger surface area and 2.5 times more reflective surface...
RACHEL
...you get an Earth that appears about 35 times brighter in the lunar sky.
PAUL
That would be one big and bright blue and white orb.
RACHEL
And unlike the moon on Earth, to an astronaut standing on the moon, Earth would remain in the same position in the sky.
PAUL
However, the phase of Earth would change over a period of 30 days.
RACHEL
In fact, the phase of Earth would be opposite of the moon’s phase on Earth.
PAUL
So when the moon is new to us, Earth is in the full phase to the moon.
RACHEL
Best yet is during the New Earth phase.
PAUL
Some times at new, Earth will pass between the moon and the sun to create an amazing total solar eclipse.
RACHEL
Because of Earth’s atmosphere, lunar inhabitants would see all of the world’s sunsets as a ring of orangey-red fire surrounding Earth.
PAUL
And the lunar surface would be illuminated in that orangey-red glow.
RACHEL
That’s Idaho Skies for the second week of February. Next week we’ll tell you how to watch the occultation of Aldebaran.
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 second week of February. We’re your hosts, Paul...
RACHEL
...and Rachel.
PAUL
The moon is new on the 8th.
RACHEL
So it reappears in the west two days later.
PAUL
Starting the 10th and for the next couple of nights, look for earthshine illuminating the dark portion of the moon.
RACHEL
And remember, earthshine is sunlight, but reflected by Earth.
PAUL
How is it possible for Earth to reflect so much towards the moon?
RACHEL
It’s because of Earth’s albedo and size.
PAUL
Explain albedo.
RACHEL
Sure, albedo is the astronomical term for reflectivity.
PAUL
And an albedo of zero is a perfect absorber of light and totally non-reflective.
RACHEL
While an albedo of 1 is perfectly reflective.
PAUL
So where does the moon’s albedo lie?
RACHEL
The moon’s albedo is 0.12
PAUL
Which is another way of saying the moon only reflects 12% of the sunlight incident on it.
RACHEL
That make the moon’s surface about as dark as an asphalt parking lot.
PAUL
And that’s on average.
RACHEL
Right, the lunar seas are darker and less reflective while the lunar highlands are just the opposite.
PAUL
So what about the Earth?
RACHEL
Earth’s albedo is 0.30.
PAUL
Most of that comes from its clouds and ice caps.
RACHEL
That’s correct; the oceans are darker.
PAUL
On average then, Earth is 2.5 times brighter than the moon.
RACHEL
So we can see that Earth is more reflective than the moon, what about their relative sizes?
PAUL
The moon’s diameter is 2,100 miles.
RACHEL
That small?
PAUL
Yep. The United States would wrap 50% of the way around the moon.
RACHEL
And I remember Earth is just about 7,900 miles in diameter.
PAUL
Which means Earth has a diameter nearly four times larger than the moon.
RACHEL
And that means about 14 times more surface area to reflect sunlight.
PAUL
Combining the 14 times larger surface area and 2.5 times more reflective surface...
RACHEL
...you get an Earth that appears about 35 times brighter in the lunar sky.
PAUL
That would be one big and bright blue and white orb.
RACHEL
And unlike the moon on Earth, to an astronaut standing on the moon, Earth would remain in the same position in the sky.
PAUL
However, the phase of Earth would change over a period of 30 days.
RACHEL
In fact, the phase of Earth would be opposite of the moon’s phase on Earth.
PAUL
So when the moon is new to us, Earth is in the full phase to the moon.
RACHEL
Best yet is during the New Earth phase.
PAUL
Some times at new, Earth will pass between the moon and the sun to create an amazing total solar eclipse.
RACHEL
Because of Earth’s atmosphere, lunar inhabitants would see all of the world’s sunsets as a ring of orangey-red fire surrounding Earth.
PAUL
And the lunar surface would be illuminated in that orangey-red glow.
RACHEL
That’s Idaho Skies for the second week of February. Next week we’ll tell you how to watch the occultation of Aldebaran.
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.
Tuesday, February 2, 2016
Transcript: January 31st to February 6th
RACHEL
Welcome to Idaho Skies for the first week of February. We’re your hosts, Rachel...
PAUL
...and Paul.
RACHEL
You’ll find a planet and a double star next to the moon on the morning of the 1st.
PAUL
The planet is Mars and the double star is Zubenelgenubi.
RACHEL
Both are located to the lower right of the first quarter moon.
PAUL
Of the three, only the moon and Zubenelgenubi are objects fit for your binoculars.
RACHEL
Mars is approaching opposition this May, so it’s growing ever closer to Earth.
PAUL
Opposition?
RACHEL
Yes, opposition. It’s when a superior planet is opposite the sun from Earth’s perspective.
PAUL
Wait, go back. Superior planet?
RACHEL
A superior planet is one that is farther from the sun than Earth.
PAUL
Oh, so you mean Mars, Jupiter, Saturn, Uranus, and Neptune.
RACHEL
That’s right.
PAUL
What makes opposition so special?
RACHEL
At opposition, superior planets are their closest to Earth and therefore appear their brightest and largest.
PAUL
In the case of Mars, opposition is very important since it’s significantly closer to Earth than any other planet.
RACHEL
Yes, and opposition lets telescopes see the greatest details possible.
PAUL
So what can we expect to see on Mars this spring?
RACHEL
Not much for binoculars, unfortunately. However, if you have a large amateur telescope, you’ll be able to see Martian features like Syrtis Major.
PAUL
What about the canals?
RACHEL
Sorry, no canals.
PAUL
Zubenelgenubi is the second binocular object you’ll see near the moon on the 1st.
RACHEL
It’s a double star that some people can split into two separate stars using just their eyes.
PAUL
To find the trio of Mars, the moon, and Zubenelgenubi, go outside at 5:30 AM on the 1st and look in the southeast.
RACHEL
The moon, Mars and Zubenelgenubi will all fit within the view of binoculars.
PAUL
Now that you know the superior planets, you know that the inferior planets are Venus and Mercury.
RACHEL
And the moon passes each in turn on the 5th and 6th.
PAUL
On the 5th, you’ll find Venus below the moon in the east.
RACHEL
In fact, it’s so bright you can’t miss it.
PAUL
Because Venus isn’t very far from the sun, you’ll need to go out between 6:30 and 6:45 AM if you want to see this pair.
RACHEL
Mercury reaches its greatest distance from the sun on the 6th.
PAUL
So on the morning of the 6th look for Mercury and Venus paired up together in the low eastern sky.
RACHEL
But there’s also some bad news.
PAUL
The tilt of Mercury’s orbit is shallow relative to the horizon.
RACHEL
That means Mercury won’t be very far above the horizon, even though it’s quite some distance from the sun.
PAUL
To find Mercury, go outside by 7:00 AM on the 6th and put Venus it in the upper right edge of your binoculars.
RACHEL
Mercury will be the star located at the lower left edge of your binoculars.
PAUL
Dawn causes the sky to brighten by 7:00 AM, so you don’t have too much time to find Mercury.
RACHEL
That’s Idaho Skies for the first week of February. Next week we’ll talk about something called albedo.
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.
Welcome to Idaho Skies for the first week of February. We’re your hosts, Rachel...
PAUL
...and Paul.
RACHEL
You’ll find a planet and a double star next to the moon on the morning of the 1st.
PAUL
The planet is Mars and the double star is Zubenelgenubi.
RACHEL
Both are located to the lower right of the first quarter moon.
PAUL
Of the three, only the moon and Zubenelgenubi are objects fit for your binoculars.
RACHEL
Mars is approaching opposition this May, so it’s growing ever closer to Earth.
PAUL
Opposition?
RACHEL
Yes, opposition. It’s when a superior planet is opposite the sun from Earth’s perspective.
PAUL
Wait, go back. Superior planet?
RACHEL
A superior planet is one that is farther from the sun than Earth.
PAUL
Oh, so you mean Mars, Jupiter, Saturn, Uranus, and Neptune.
RACHEL
That’s right.
PAUL
What makes opposition so special?
RACHEL
At opposition, superior planets are their closest to Earth and therefore appear their brightest and largest.
PAUL
In the case of Mars, opposition is very important since it’s significantly closer to Earth than any other planet.
RACHEL
Yes, and opposition lets telescopes see the greatest details possible.
PAUL
So what can we expect to see on Mars this spring?
RACHEL
Not much for binoculars, unfortunately. However, if you have a large amateur telescope, you’ll be able to see Martian features like Syrtis Major.
PAUL
What about the canals?
RACHEL
Sorry, no canals.
PAUL
Zubenelgenubi is the second binocular object you’ll see near the moon on the 1st.
RACHEL
It’s a double star that some people can split into two separate stars using just their eyes.
PAUL
To find the trio of Mars, the moon, and Zubenelgenubi, go outside at 5:30 AM on the 1st and look in the southeast.
RACHEL
The moon, Mars and Zubenelgenubi will all fit within the view of binoculars.
PAUL
Now that you know the superior planets, you know that the inferior planets are Venus and Mercury.
RACHEL
And the moon passes each in turn on the 5th and 6th.
PAUL
On the 5th, you’ll find Venus below the moon in the east.
RACHEL
In fact, it’s so bright you can’t miss it.
PAUL
Because Venus isn’t very far from the sun, you’ll need to go out between 6:30 and 6:45 AM if you want to see this pair.
RACHEL
Mercury reaches its greatest distance from the sun on the 6th.
PAUL
So on the morning of the 6th look for Mercury and Venus paired up together in the low eastern sky.
RACHEL
But there’s also some bad news.
PAUL
The tilt of Mercury’s orbit is shallow relative to the horizon.
RACHEL
That means Mercury won’t be very far above the horizon, even though it’s quite some distance from the sun.
PAUL
To find Mercury, go outside by 7:00 AM on the 6th and put Venus it in the upper right edge of your binoculars.
RACHEL
Mercury will be the star located at the lower left edge of your binoculars.
PAUL
Dawn causes the sky to brighten by 7:00 AM, so you don’t have too much time to find Mercury.
RACHEL
That’s Idaho Skies for the first week of February. Next week we’ll talk about something called albedo.
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.
Procyon has twice the diameter of our sun due to its 70% greater mass. Its greater temperature and diameter combine to make Procyon over seven times more luminous than the Sun. Procyon has consumed enough of its hydrogen that it can now fuse helium. In several tens of millions of years, just a blip of time for our sun, Procyon will expand into a red giant star.
White dwarf companion stars orbit both Procyon and Sirius. White dwarfs are stars that have consumed their supply of nuclear fuel. Without fusion to support them, gravity has compressed them into spheres the size of planets, or about 100 times smaller that they use to be. This means a cubic centimeter of white dwarf weighs about a ton. So imagine your car fitting on a teaspoon.
You’ll find Procyon half way up in the south-southeast early February nights.
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