RACHEL
Welcome to Idaho Skies for the third week of June. We’re your hosts, Rachel…
PAUL
…and Paul.
RACHEL
The moon is first quarter on the 16th.
PAUL
That means it’s time to dust off your old pair of binoculars and take a gander at the moon.
RACHEL
Craters are noticeable in your binoculars, especially in the southern half of the moon.
PAUL
Your best lunar views come from bracing your arms on something sturdy, like a tree or fence.
RACHEL
That way the shaking in your arms will not blur the view.
PAUL
On the 18th, the moon sits between the star Spica and the planet Saturn.
RACHEL
Spica is closer to the moon while Saturn is farther away.
PAUL
You’ll be able to see either the moon and Spica together in binoculars or the moon and Saturn together, but not all three simultaneously.
RACHEL
When you observe Saturn, you’ll see that the star Kappa Virginis in the constellation Virgo is close to Saturn’s upper right.
PAUL
But they’re not close in space. Saturn is 76 light minutes away while Kappa Virginis is 224 light years away.
RACHEL
So the light you see from Saturn only left an hour and fifteen minutes ago while the light of Kappa Virginis left in the year 1789.
PAUL
Thirty years ago on the 18th, the United States launched the first American woman into Earth orbit aboard the Space Shuttle.
RACHEL
Sally Ride was 32 years old when she traveled to space and she still remains the youngest American to travel into space.
PAUL
Sally spent a total of two weeks in space during her two Space Shuttle flights. Both of her flights were on board the Space Shuttle Challenger.
RACHEL
Sally was not the first woman in space, however. She was preceded into space by Soviet cosmonauts Valentina Tereshkova in 1963 and Svetlana Savitskaya in 1982.
PAUL
This week Venus is rising higher above the horizon and Mercury is approaching the horizon.
RACHEL
So the two inner planets cross paths once again on the evening of June 20th.
PAUL
Mercury will be to the lower left of brighter Venus.
RACHEL
They’ll be close enough together that both will be visible together in your binoculars.
PAUL
Begin looking for the pair of planets by 10:00 PM, after the sun has set.
RACHEL
While you’re searching for Venus and Mercury, you may notice there are two stars above and to the right of Venus.
PAUL
These are the brightest two stars of Gemini, Pollux and Castor.
RACHEL
Summer in the northern hemisphere begins late on the evening of the 20th.
PAUL
That means on the 20th, daylight lasts it’s longest for the year.
RACHEL
In Boise, our first day of summer will be 15 hours and 23 minutes long.
PAUL
That’s Idaho Skies for the third week of June. Next week we’ll discuss the full moon, its proximity to Earth, and what effect this will have on us.
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.
Sunday, June 9, 2013
Transcript for June 9 - 15
PAUL
Welcome to Idaho Skies for the second week of June. We’re your hosts, Paul…
RACHEL
…and Rachel.
PAUL
On the evening of the 10th, the young crescent moon passes very close to Mercury and Venus.
RACHEL
You’ll need to look for this trio of astronomical objects after 10:00 PM, but before 10:30. You’ll need a clear west-northwestern horizon to see them, as they will be low.
PAUL
The 10th also marks the tenth anniversary of the launch of the Spirit Mars Rover.
RACHEL
Spirit was one of two solar-powered rovers launched to the red planet in 2003.
PAUL
For six years, Spirit traversed the Martian surface looking for evidence of water in Mars’ past.
RACHEL
The rover traveled nearly five miles during its search and made multiple measurements of the Martian rocks near the Columbia Hills.
PAUL
Spirit’s instruments detected slight chemical alterations in the composition of the outer layers of rocks.
RACHEL
It also found a type of chemical called sulfates in the Martian soil.
PAUL
These results indicated that water was present in the Martian past.
RACHEL
However, the amount was small compared to the amount of water found on Earth.
PAUL
Spirit’s mission ended after it became stuck in soft Martian sand.
RACHEL
Unable to extract itself from the loose sand, Spirit couldn’t properly orient its solar array for the approaching winter.
PAUL
The limited amount of sunlight available during the winter prevented Spirit’s solar array from acquiring enough power to survive the brutal cold.
RACHEL
On June 12th, Mercury is at its greatest eastern elongation.
PAUL
Elongation is a property of the orbits of inner planets and not outer planets.
RACHEL
Inner planets, which astronomers call inferior planets are those that orbit closer to the sun than Earth.
PAUL
Like Mercury and Venus.
RACHEL
And superior planets are those that orbit the sun farther than Earth.
PAUL
Since inferior planets reside closer to the sun than Earth, we will never see them in the sky opposite of the sun.
RACHEL
The greatest distance away from the sun that we see an inferior planet is called its greatest elongation.
PAUL
Because of its small orbit, Mercury can only travel 24 degrees away from the sun.
RACHEL
That sounds impressive. After all, 24 degrees is nearly 1/3rd of the distance from the horizon to overhead.
PAUL
That would be correct if Boise was located on the equator. However, at a latitude of 43 degrees north, Mercury’s orbit around the sun is very slanted with respect to our local horizon.
RACHEL
So how far above the horizon will Mercury appear when its 24 degrees from the sun?
PAUL
Our solar system’s smallest planet will only appear ten degrees above horizon at 10:00 PM. That means by 10:45, the planet will be all but impossible to see.
RACHEL
Hey, the earliest sunrise this year occurs on the 13th!
PAUL
That means from now until mid December, the sun will set earlier each night.
RACHEL
That’s Idaho Skies for the second week of June. Next week the moon passes close to Saturn, so you will have more than just Mercury and Venus to observe.
PAUL
Be sure to read our blog for additional information. It’s at idahoskies dot blogspot dot 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 June. We’re your hosts, Paul…
RACHEL
…and Rachel.
PAUL
On the evening of the 10th, the young crescent moon passes very close to Mercury and Venus.
RACHEL
You’ll need to look for this trio of astronomical objects after 10:00 PM, but before 10:30. You’ll need a clear west-northwestern horizon to see them, as they will be low.
PAUL
The 10th also marks the tenth anniversary of the launch of the Spirit Mars Rover.
RACHEL
Spirit was one of two solar-powered rovers launched to the red planet in 2003.
PAUL
For six years, Spirit traversed the Martian surface looking for evidence of water in Mars’ past.
RACHEL
The rover traveled nearly five miles during its search and made multiple measurements of the Martian rocks near the Columbia Hills.
PAUL
Spirit’s instruments detected slight chemical alterations in the composition of the outer layers of rocks.
RACHEL
It also found a type of chemical called sulfates in the Martian soil.
PAUL
These results indicated that water was present in the Martian past.
RACHEL
However, the amount was small compared to the amount of water found on Earth.
PAUL
Spirit’s mission ended after it became stuck in soft Martian sand.
RACHEL
Unable to extract itself from the loose sand, Spirit couldn’t properly orient its solar array for the approaching winter.
PAUL
The limited amount of sunlight available during the winter prevented Spirit’s solar array from acquiring enough power to survive the brutal cold.
RACHEL
On June 12th, Mercury is at its greatest eastern elongation.
PAUL
Elongation is a property of the orbits of inner planets and not outer planets.
RACHEL
Inner planets, which astronomers call inferior planets are those that orbit closer to the sun than Earth.
PAUL
Like Mercury and Venus.
RACHEL
And superior planets are those that orbit the sun farther than Earth.
PAUL
Since inferior planets reside closer to the sun than Earth, we will never see them in the sky opposite of the sun.
RACHEL
The greatest distance away from the sun that we see an inferior planet is called its greatest elongation.
PAUL
Because of its small orbit, Mercury can only travel 24 degrees away from the sun.
RACHEL
That sounds impressive. After all, 24 degrees is nearly 1/3rd of the distance from the horizon to overhead.
PAUL
That would be correct if Boise was located on the equator. However, at a latitude of 43 degrees north, Mercury’s orbit around the sun is very slanted with respect to our local horizon.
RACHEL
So how far above the horizon will Mercury appear when its 24 degrees from the sun?
PAUL
Our solar system’s smallest planet will only appear ten degrees above horizon at 10:00 PM. That means by 10:45, the planet will be all but impossible to see.
RACHEL
Hey, the earliest sunrise this year occurs on the 13th!
PAUL
That means from now until mid December, the sun will set earlier each night.
RACHEL
That’s Idaho Skies for the second week of June. Next week the moon passes close to Saturn, so you will have more than just Mercury and Venus to observe.
PAUL
Be sure to read our blog for additional information. It’s at idahoskies dot blogspot dot com. For Idaho Skies this is Paul…
RACHEL
and Rachel.
PAUL
Dark skies and bright stars.
The light of Arcturus opened the 1933 World’s Fair in Chicago. At that time, the best measurement of the distance to this star pegged it at 40 light years. Since the previous World’s Fair in Chicago occurred forty years earlier, the starlight seen from Arcturus at the opening of the 1933 fair had left the star during the last fair. To open the 1933 World’s Fair, a large telescope lens focused the Arcturian starlight on a photocell (a light-sensitive resistor). The electrical signal generated by the star’s light shining on the photocell was used to switch on the lights of the fair.
Arcturus is a spectral type K star, meaning its cooler than our sun and produces less light per square foot of surface. Instead of being yellow like our sun (which is a G spectral type), Arcturus is a cooler orange. However, because of its larger diameter, Arcturus shines over 100 times more brightly than our sun. If its infrared radiation is included, then the star is over 200 times brighter than our sun. It would take 26 of our suns to span the diameter of Arcturus. If the star replaced the sun in our sky, it would cover an area of the sky two times larger than the palm of your outstretched hand. The surface of Arcturus would reach one-quarter of the way to the orbit of Mercury. Of course, the larger mass, diameter, and radiation from Arcturus would end all life on Earth with the possible exception of bacteria living far underground.
To find Arcturus, follow the bend of the handle of the Big Dipper. An arc drawn from the end of the Dipper’s handle (actually the Large Bear’s tail) leads you to Arcturus. In June, Arcturus passes almost directly overhead.
Monday, June 3, 2013
Transcript for June 2 - 8
RACHEL
Welcome to Idaho Skies for the first week of June. We’re your hosts, Rachel…
PAUL
… and Paul.
RACHEL
Now is the time to observe Mercury, Venus, and Jupiter.
PAUL
Our solar system’s two innermost planets remain close to Jupiter and all three are visible in the western evening sky.
RACHEL
Since Jupiter and Venus are so bright, they make it easier to locate Mercury.
PAUL
To see them, look low in the west-northwestern horizon about 30 minutes after sunset on the 1st.
RACHEL
That evening, Jupiter, Venus, and Mercury will form a straight line that is inclined towards the upper-left.
PAUL
Jupiter will be the lowest and very near the horizon. Venus is brighter and is located to Jupiter’s upper left.
RACHEL
To locate Mercury, just draw a straight line upwards from Jupiter to Venus. Mercury is located the same distance above Venus.
PAUL
Venus continues climbing higher above the horizon this summer.
RACHEL
Jupiter, on the other hand, is passing behind the sun soon and will reappear in the morning sky in another month.
PAUL
What about Mercury? What is its motion in June?
RACHEL
Mercury will climb a bit higher above the horizon until June 10th. Then it will begin approaching the sun, from Earth’s perspective.
PAUL
On the 4th, Venus is just above a cluster of stars named M-35.
RACHEL
It will be difficult to see very well because the sun will have recently set and it will still be dawn.
PAUL
You’ll need to search for this star cluster just below Venus after 10 PM.
RACHEL
However, you won’t have long, Venus sets at 10:30.
PAUL
Speaking of dawn, did you know that there are three types of twilight?
RACHEL
That’s right. The first is called civil twilight. Civil twilight ends when the center of the sun is 6 degrees below the horizon.
PAUL
At the end of civil twilight, we can only see the brightest stars. However, it is dark enough that state laws require us to turn on our car headlights.
RACHEL
The second is nautical twilight. This ends when the center of the sun is 12 degrees below the horizon.
PAUL
At the end of nautical twilight, sailors cannot navigate using observations that require them to see the horizon; the horizon is too dark to distinguish from the sky.
RACHEL
The last is astronomical twilight. At the end of astronomical twilight, the center of the sun is 18 degrees below the horizon.
PAUL
At the end of astronomical twilight, the sky is as dark as it will get. We can see the faintest stars.
RACHEL
The moon is new on the 8th, so you won’t see it for a day or two at best.
PAUL
However, it’s a good time to see faint objects through your telescope or binoculars.
RACHEL
That’s Idaho Skies for the first week of June. Join us next week to hear more about the innermost planets of our solar system.
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 June. We’re your hosts, Rachel…
PAUL
… and Paul.
RACHEL
Now is the time to observe Mercury, Venus, and Jupiter.
PAUL
Our solar system’s two innermost planets remain close to Jupiter and all three are visible in the western evening sky.
RACHEL
Since Jupiter and Venus are so bright, they make it easier to locate Mercury.
PAUL
To see them, look low in the west-northwestern horizon about 30 minutes after sunset on the 1st.
RACHEL
That evening, Jupiter, Venus, and Mercury will form a straight line that is inclined towards the upper-left.
PAUL
Jupiter will be the lowest and very near the horizon. Venus is brighter and is located to Jupiter’s upper left.
RACHEL
To locate Mercury, just draw a straight line upwards from Jupiter to Venus. Mercury is located the same distance above Venus.
PAUL
Venus continues climbing higher above the horizon this summer.
RACHEL
Jupiter, on the other hand, is passing behind the sun soon and will reappear in the morning sky in another month.
PAUL
What about Mercury? What is its motion in June?
RACHEL
Mercury will climb a bit higher above the horizon until June 10th. Then it will begin approaching the sun, from Earth’s perspective.
PAUL
On the 4th, Venus is just above a cluster of stars named M-35.
RACHEL
It will be difficult to see very well because the sun will have recently set and it will still be dawn.
PAUL
You’ll need to search for this star cluster just below Venus after 10 PM.
RACHEL
However, you won’t have long, Venus sets at 10:30.
PAUL
Speaking of dawn, did you know that there are three types of twilight?
RACHEL
That’s right. The first is called civil twilight. Civil twilight ends when the center of the sun is 6 degrees below the horizon.
PAUL
At the end of civil twilight, we can only see the brightest stars. However, it is dark enough that state laws require us to turn on our car headlights.
RACHEL
The second is nautical twilight. This ends when the center of the sun is 12 degrees below the horizon.
PAUL
At the end of nautical twilight, sailors cannot navigate using observations that require them to see the horizon; the horizon is too dark to distinguish from the sky.
RACHEL
The last is astronomical twilight. At the end of astronomical twilight, the center of the sun is 18 degrees below the horizon.
PAUL
At the end of astronomical twilight, the sky is as dark as it will get. We can see the faintest stars.
RACHEL
The moon is new on the 8th, so you won’t see it for a day or two at best.
PAUL
However, it’s a good time to see faint objects through your telescope or binoculars.
RACHEL
That’s Idaho Skies for the first week of June. Join us next week to hear more about the innermost planets of our solar system.
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.
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