Monday, September 26, 2016

Idaho skies Transcript for September 30th to October 2nd

PAUL
Welcome to Idaho Skies for September 30th and October 1st and 2nd. We’re your hosts, Paul…

RACHEL
…and Rachel.

PAUL
Don’t forget to look for Mercury in the morning this weekend.

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It’s already reached its highest distance above the horizon…

PAUL
…and is rapidly approaching the horizon again.

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To see Mercury, go outside at about 6:30 AM.

PAUL
And look for a star very low in the east.

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The star is bright enough that you’ll have no trouble finding it.

PAUL
The only problem might be is having a horizon too high for Mercury to clear before sunrise.

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Did you know that a year on Mercury only lasts for 88 Earth days?

PAUL
And a day last 58 Earth days?

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Mercury also has a much more elliptically shape orbit than Earth.

PAUL
Its elliptical orbit means the orbital speed of the planet changes more dramatically than it does for Earth.

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By traveling faster as it approaches the sun…

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…and slower as it travels away from the sun.

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Combining its changing orbital speed and rotational rate means the sun doesn’t travel neatly from one horizon to the other as it does on Earth.

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In fact, the sun actually moves backwards across the sky for part of a Mercurian day.

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Before 1974, astronomers thought that Mercury’s day lasted as long as its year.

PAUL
This is called being tidally locked and it happens to astronomical bodies orbiting close to their parent.

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In the case of Mercury, its year lasts 1.5 days and perhaps in the future, the day and year will come into sync.

PAUL
That’s Idaho Skies for the 30th, 31st of September and the 1st of October.

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.

Idaho Skies Transcript for September 28th and 29th

RACHEL
Welcome to Idaho Skies for September 28th and 29th. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
Mercury reaches greatest western elongation on the 28th.

PAUL
Western elongation occurs when an inferior planet…

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…or a planet located between Earth and the sun…

PAUL
…reaches its greatest extent from the sun from Earth’s perspective.

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That means the planet appears as far from the sun as possible.

PAUL
If the inclination of the planet’s obit is steep with respect to the horizon, then the planet also appears at its highest point above the horizon also.

RACHEL
Fortunately, the orbits of the planets appear very steep with respect to the horizon in the Autumn.

PAUL
So September is a good month for western elongations.

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To find Mercury at its greatest western elongation, go outside on the 28th at 6:30 AM.

PAUL
Mercury will appear as a reasonable bright white star low in the east.

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Binoculars are not needed to see tiny Mercury.
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Besides, the planet is far too small and distant to show details even through a telescope.

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Although, there have been a few sightings of surface details in very special cases.

PAUL
Its largest structure is the Caloris Basin

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At 960 miles across, it’s one of the largest impact basins in the solar system.

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Edging the Caloris basin are mountain ranges thrown up by the impact.

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Some of those mountains are 1.2 miles tall.

PAUL
Above Mercury, you’ll also find the very thin crescent moon.

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Now use your binoculars and see if your can detect Earthshine.

PAUL
It’s the reflected sunlight illuminating the dark portion of the moon.
  
RACHEL
That’s Idaho Skies for the 28th and 29th of September.

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.

Idaho Skies Transcript for September 26th and 27th

PAUL
Welcome to Idaho Skies for September 26th and 27th. We’re your hosts, Paul…

RACHEL
…and Rachel.

PAUL
On the morning of the 26th, the Beehive star cluster is visible 6.5 degrees to moon’s upper left.

RACHEL
Even closer to the moon’s right is M-67, although it’s a smaller star cluster than the Beehive.

PAUL
Both star clusters belong to the constellation Cancer the Crab.

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To find the Beehive, point your binoculars at the moon and shift your gaze nearly straight up.

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Soon after the moon leaves, a tight bundle of stars will enter from the top.

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The other star cluster, M-67 is easier to find, but more difficult to see on account of its smaller size.

PAUL
Again point your binoculars at the moon, but this time, don’t move them.

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Just off the right edge of the moon, you’ll see M-67.

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It should appear as a small fuzzy spot.

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The very thin crescent moon picks up a companion star on the morning of the 27th.
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The star’s name is Regulus and it’s located at the moon’s lower left.

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Stargazers might remember Regulus from last spring.

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It’s the brightest star of Leo the Lion.

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Its color and position means its represents the heart of Leo.

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Use your binoculars and see if you can detect Earthshine.

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If you can, then see if you can detect some of the lunar seas on the dark portion of the moon.

PAUL
If you where an astronaut on the moon, you would see the nearly full Earth overhead.

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And it would be four times larger and about 16 times brighter than the moon appears to us.

PAUL
That’s Idaho Skies for the 26th and 27th of September.

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, September 12, 2016

Transcript for September 16th to 18th

PAUL
Welcome to Idaho Skies for September 16th, 17th, and 18th. We’re your hosts, Paul…

RACHEL
…and Rachel.

PAUL
Uranus is an ice giant and the solar system’s 6th planet.

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Giant is right; its diameter is four times greater than Earth’s.

PAUL
Astronomer William Hershel discovered Uranus telescopically over 230 year ago.

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However, the planet can just reach naked eye visibility and is therefore visible without a telescope.

PAUL
But just barely.

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This means it’s quite easy to see through binoculars.

PAUL
However, due to its faintness, it helps when a brighter object is near by.

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As is the moon on the 18th.

PAUL
On the 18th at around 11 PM, place the moon at the bottom of your binoculars.

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Look at the star just to the left of the moon and become familiar with its brightness.

PAUL
Then go nearly straight up for a binoculars field of view to find a second star that’s the same brightness as the first.

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Look right of that second star and you’ll see a line of three fainter stars.

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The third star is Uranus.

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You can confirm that this is Uranus by moving your binoculars straight down.

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Because the moon will enter the view at the bottom just after Uranus leaves the top.

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Uranus is so far away that you’re seeing the planet 159 minutes ago.

PAUL
For a reference, you’re seeing the moon only 1.5 seconds ago.

RACHEL
That’s Idaho Skies for the 16th, 17th, and 18th of September. 

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 September 14th and 15th

RACHEL
Welcome to Idaho Skies for September 14th and 15th. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
The moon has company on the 14th.

PAUL
The region surrounding the moon tonight is considered a watery part of the sky and its only bright star is Fomalhaut.

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Fomalhaut is the alpha star of the constellation of Pisces Austrinus…

PAUL
…also known to stargazers as the Southern Fish.

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Fomalhaut marks the mouth of the fish, which is swimming eastward.

PAUL
Above Pisces Austrinus is the constellation of Aquarius the Water Bearer.

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Aquarius appears as a man pouring water out of an opened jar.

PAUL
And the fish below him is swallowing the water he is pouring from his jar.

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At least that’s what the sky charts would have you believe.

PAUL
Did you know that Fomalhaut is a young star, compared to the sun.

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How can astronomers tell?

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On way is by detecting a dusty cocoon surrounding the star.

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Stars form inside of disks of gas and dust.

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And the dust is the remains of the cloud that formed Fomalhaut.

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Planets are also born from the cloud that lead to Fomalhaut.

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In fact, the Hubble Space Telescope was able to detect one of those planets in 2008.

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The planet has since been named Dagon.

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The name Dagon came from the name of a Mesopotamian fish god.

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So remember that solitary white star you’ll see below the moon on the night of the 14th is Fomalhaut and it has at least one companion planet.

PAUL
That’s Idaho Skies for the 14th and 15th of September.

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.

Transcript for September 12th and 13th

PAUL
Welcome to Idaho Skies for September 12th and 13th. We’re your hosts, Paul…

RACHEL
…and Rachel.

PAUL
The inner solar system is filled with the dust of asteroid collisions.

RACHEL
The dust grains remain in orbit around the sun until the pressure of sunlight gradually slows them down.

PAUL
As they slow down, their orbits get closer to the sun.

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Until as some point, intense sunlight vaporizes the dust.

PAUL
However, as the dust grains are being vaporized, asteroid collisions are creating additional dust.

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Did you know that stargazers can see this dust?

PAUL
What, see dust tens of millions of miles away?

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You can see it because of the sunlight it reflects.

PAUL
It’s called the Zodiacal Light and its best seen on mid-September mornings and mid-March evenings.

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But only when the moon is not visible.

PAUL
As is the case this week.

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You can see the Zodiacal Light if you first find dark skies.

PAUL
You’ll need to look in the east about two hours before sunrise.

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Or around 5:30 AM.

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The Zodiacal Light or False Dawn will appear as a pillar of light.

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The light forms a pillar rising out of the east that’s tilted towards the south.

PAUL
It will be about as bright at the beginning of dawn, but it occurs about an hour earlier.

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And the Zodiacal Light won’t hug the horizon like dawn.

PAUL
So get outside on September and October mornings where there’s no moonlight.

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And look for the false dawn standing up like a pillar.

PAUL
That’s Idaho Skies for the 12th and 13th of September.

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.

Tuesday, September 6, 2016

Transcript for September 9th to 11th

RACHEL
Welcome to Idaho Skies for September 9th, 10th, and 11th. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
The moon reaches first quarter phase on the evening of the 9th.

PAUL
First quarter phase is a great time to observe the moon in your binoculars or small telescope.

RACHEL
Because that’s when the boundary between day and night is turned directly towards Earth.

PAUL
As a result, the shadows cast by the rising sun extend their greatest distance across the lunar surface, from our perspective.

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Those stretched out shadows accentuate even small changes in lunar elevation.

PAUL
And that helps to make the moon’s surface appear more jagged than it actually is.

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In reality, the lunar surface is for the most part, rounded and very dusty.

PAUL
That’s the result from the relentless bombardment of micrometeorites and cosmic rays that the moon experiences.

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Mars is the bright orangish star that you’ll find to the lower left of the moon on the 9th.

PAUL
The distance between the moon and Mars is too great for both to be seen together in binoculars.

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Besides, Mars appears as just an orange star in binoculars.

PAUL
When you look at Mars, remember that there are two robots traversing its surface.

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The oldest is named Opportunity and it’s been on Mars since 2004.

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The newest is named Curiosity and it landed in August 2012.

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Wait; wasn’t Opportunity accompanied by a twin rover?

PAUL
Yep. It’s companion rover was named Spirit.

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Unfortunately, it stopped working after spending over 2,200 days traversing Mars

PAUL
Not bad for a rover designed for a 90 day mission.

RACHEL
That’s Idaho Skies for the 9th, 10th, and 11th of September.

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.