Sunday, April 13, 2014

Transcript of April 13 - 19

RACHEL Welcome to Idaho Skies for the third week of April. We’re your hosts, Rachel... PAUL ...and Paul. RACHEL There are some great astronomical opportunities this week. PAUL To begin with, Earth passes its closest to Mars on the 14th. RACHEL That night bright orange Mars appears above the full moon. PAUL The moon is full on the night of the 14th and morning of the 15th. RACHEL Many Americans name April’s full moon the Egg Moon. PAUL However, this year’s Egg Moon is a bit different from usual RACHEL That’s because it turns a shade of orange, like nearby Mars. PAUL This month’s lunar eclipse begins around 11:30 PM on the 14th. RACHEL That’s when a darkening should appear on the left edge of the moon. PAUL The moon will continue drifting deeper into Earth’s shadow over the next hour and 45 minutes. RACHEL By then, the moon will glow somewhere between a deep red and a light orange. PAUL Wait. If the moon is passing though Earth’s shadow, why is glowing at all? RACHEL Well, Earth does block direct light from the sun, but Earth’s atmosphere bends and refracts red light from the sun. PAUL This refraction results in the moon’s illumination by all of the sunsets occurring along the rim of Earth. RACHEL The exact shade of the moon depends on the clarity of Earth’s atmosphere at the time of the eclipse. PAUL You can continue to observe the eclipse until 4:00 AM on the morning of the 15th. RACHEL Try recording the eclipse with your digital camera. PAUL You’ll need to attach your camera to a tripod in order to keep the camera motionless long enough for the exposure. RACHEL Set the camera’s optical zoom to its maximum magnification and manually focus the camera on infinity. PAUL Record several images in a row and vary the shutter speed each time. RACHEL The bright double star, Zubenelgenubi appears to the moon’s left on the night of the 15th and morning of the 16th. PAUL Zubenelgenubi is the star to the moon’s lower left. RACHEL Saturn is the brighter star and farther away to the moon’s left. PAUL Your binoculars show that Zubenelgenubi is actually a pair stars. RACHEL On the morning of the 17th, Saturn is just above the moon. PAUL It will be very close, just twice the moon’s apparent diameter away. RACHEL A small telescope shows Saturn’s rings and you don’t need very much magnification. PAUL Yep. Just 25 power is enough to begin seeing the rings. RACHEL That’s Idaho Skies for the third week of April. Next week we’ll be observing the Lyrid meteor shower and Venus. 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.

Sunday, April 6, 2014

Transcript for April 6-12

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

PAUL
...and Paul.

RACHEL
Got Jupiter?

PAUL
Jupiter is the brightest star above the moon’s upper right on the evening of the 6th.

RACHEL
In a pair of binoculars, you should be able to detect two of its moons, Callisto and Europa.

PAUL
You’ll need to hold the binoculars really steady, so prop them up on something like a car, fence, or tree branch.

RACHEL
Callisto will be the star farthest from Jupiter’s right.

PAUL
Smaller Europa is located about half way between Callisto and Jupiter.

RACHEL
The remaining Galilean satellites are too close to Jupiter to see through binoculars.

PAUL
So to see them, you’ll get your telescope out.

RACHEL
The moon is first quarter on the 6th. PAUL This is an excellent time to observe it in binoculars or small telescope.

RACHEL
One of the larger and brighter star clusters is located near the moon on the evening of the 8th.

PAUL
It’s called the Beehive and the ancients used it to predict the weather.

RACHEL
The star cluster is still visible to the unaided eye, but you’ll need to go south of Boise for sufficiently dark skies.

PAUL
However, don’t worry if you’re stuck in town.

RACHEL
You can still it through your binoculars.

PAUL
To observe it, center your binoculars on the moon and follow its terminator going north.

RACHEL
The star cluster is just three degrees above the moon.

PAUL
If you place the moon at bottom of your binocular’s field of view, the Beehive will appear near the center.

RACHEL
Mars reaches opposition on the 8th.

PAUL
At opposition, outer planets like Mars are located opposite of the sun in our sky.

RACHEL
Planets at opposition are also at their closest to Earth.

PAUL
This means Mars is now at its brightest for 2014.

RACHEL
And we mean bright.

PAUL
Mars will be as bright as the brightest star, Sirius.

RACHEL
There are two major differences between Mars and Sirius. First, Mars won’t twinkle like Sirius.

PAUL
And second, Mars is distinctly orange in color rather than white like Sirius.

RACHEL
A very large and diffuse star cluster is located above the moon on the 12th.

PAUL
The star cluster is called Melotte 111.

RACHEL
Mel 111 is so large that it will fill your binoculars with a scattering of stars.

PAUL
To see it, place the moon at the bottom of binocular’s field of view.

RACHEL
At top of your field of view is the tip of a large inverted "V" shaped star cluster.

PAUL
For your best views, head out of town.

RACHEL
And be sure to raise your binoculars high enough to move the moon out of sight.

PAUL
That’s Idaho Skies for the second week of April. Next week the full moon turns orange as it passes through Earth’s shadow.

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, March 31, 2014

Transcript for March 31 - April 5

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

RACHEL
...and Rachel.

PAUL
The moon is one of the most recognizable astronomical objects.

RACHEL
It’s attracted the attention of humans because of its brightness and ever changing shape.

PAUL
The moon again attracts our attention on the first of the month.

RACHEL
That’s when you’ll find its very thin crescent in the low west shortly after sunset.

PAUL
The moon will only be two and a half days old.

RACHEL
That’s a younger moon than most people have seen.

PAUL
To observe the young crescent moon, you’ll need to begin searching shortly after sunset and as the sky is beginning to darken.

RACHEL
That’s because by the time the sky gets completely dark, the moon will have already set.

PAUL
Your binoculars will make it much easier to find this astronomical treat.

RACHEL
However, please do not begin searching with binoculars until after the sun has set.

PAUL
The moon passes through the edge of the Hyades star cluster on the night of the 3rd.

RACHEL
The stars in the Hyades star cluster represent the five daughters of Atlas, the Titan of Greek mythology.

PAUL
The cluster is only 152 light years away.

RACHEL
That puts it closer to Earth than any other star cluster.

PAUL
This is the major reason why the cluster appears so large in our sky.

RACHEL
Telescopes detect hundreds of stars in this cluster.

PAUL
However, we can only see about two dozen through binoculars.

RACHEL
Take a peek with your binoculars and you’ll discover that the Hyades star cluster appears much larger than the moon.

PAUL
The moon and Hyades make a nice photographic target for your digital camera.

RACHEL
You’ll need an exposure several seconds long in order to record images of the stars in your picture.

PAUL
To record an image several seconds long means you’ll need to attach your camera to a camera tripod.

RACHEL
Unfortunately, the exposure will over-expose the moon.

PAUL
However, since the moon is crescent shaped, the picture may show signs of Earthshine on the moon.

RACHEL
Earthshine is the faint illumination of the dark portion of the moon.

PAUL
This faint light comes from sunlight reflecting off Earth.

RACHEL
It’s bright enough however to show markings on the moon.

PAUL
That’s Idaho Skies for the first week of April. Next week the moon points us at two very nice star clusters.

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.

April's Star


This month look for the star Dubhe, the alpha star of the constellation Ursa Major or the Big Dipper. On April evenings, when the Big Dipper is upside-down and pouring water into the Little Dipper, Dubhe is the lower left star in the bowl of the Big Dipper. Dubhe, which is Arabic for “The Bear” is 124 light years away. The light you see tonight left the star in 1890.

Dubhe is a multiple star system consisting of two pairs of stars orbiting each other. Dubhe A and Dubhe B are the star pair we see in the Big Dipper. Dubhe B and A are orbiting each other at a distance a little greater than the distance between the Sun and Uranus. At 124 light years away, Dubhe A and B are too close together to allow most telescopes to see them as separate stars. The second pair of stars is Dubhe C and Dubhe D and they too are also too close together for telescopes to see as separate stars. They orbit the A and B pair at a distance of 1 trillion miles. This means light takes two months to travel the distance between the A and B pair and the C and D pair.

Dubhe A is an orange star, that’s 30 times larger and 300 times brighter than our sun. It’s an old star and its core is fusing helium ash into carbon and oxygen. Outside of its core lies a shell of fusing hydrogen. Unlike Earth, the helium inside Dubhe sinks downwards in the core. That’s because helium is heavier than the hydrogen from where it originated.

Dubhe is one half of the Pointer Stars in the Big Dipper, the other star being the star above it. Follow the Pointers and you’ll run into Polaris, the brightest and closest star to the north celestial pole.

Sunday, March 23, 2014

Idaho Skies Transcript for 23 to 29 March

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

PAUL
...and Paul.

RACHEL
On the morning of the 27th, you can see the crescent moon close to the Morning Star, Venus.

PAUL
The moon will be three days from new, so it will appear as a very thin crescent.

RACHEL
The distance between the crescent moon and Venus will be three degrees, or roughly the width of three fingers in your outstretched hand.

PAUL
That means the pair will also fit very nicely within the view of a pair of binoculars.

RACHEL
You’ll need to go outside at 5:30 AM to see alignment between Venus and the moon.

PAUL
Be sure to search the low east-southeast horizon.

RACHEL
If you have a camera and tripod, you might want to take a picture of this astronomical event.

PAUL
You’ll need a tripod in order to hold the camera steady during the exposure.

RACHEL
The exposure time could be a second or more long.

PAUL
This also means you’ll want to use a cable release to trigger the camera’s shutter rather than trying to push the shutter button by hand.

RACHEL
A cable release is a flexible steel cable that creates a second shutter button that’s not attached directly to the camera.

PAUL
That way, any shaking that comes from pushing the shutter button isn’t transferred to the camera itself.

RACHEL
To increase your chances of a great picture, try taking several pictures with different camera settings.

PAUL
The second new moon of March occurs on the 30th.

RACHEL
The second full moon has been traditionally called the Blue Moon for several decades at least.

PAUL
So what should we call the second new moon of the month?

RACHEL
Phil Plait of the website Bad Astronomy mentions calling it the Black Moon.

PAUL
You might try looking for the 33 hour old moon on March 31st.

RACHEL
You’ll need a low and clear western horizon.

PAUL
That should make the parking lot at Bogus Basin an ideal location.

RACHEL
Start scanning along the western horizon beginning at 7:55 PM.

PAUL
The moon will only be five degrees above the horizon, so the ground and moon will appear within the field of view of the binoculars.

RACHEL
The moon will set by 8:20.

PAUL
Good luck finding this very young moon

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

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.

Sunday, March 16, 2014

Transcript for March 16-22

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

RACHEL
...and Rachel.

PAUL
The moon glides between Mars and the star Spica on the morning of the 19th.

RACHEL
The trio will almost close enough together to be seen at the same time through a pair or binoculars.

PAUL
How can you tell the difference between the Mars and Spica?

RACHEL
Mars is the much brighter orange-colored star to the upper right of the moon.

PAUL
And Spica, which is the brightest star of Virgo, is pure white and located a little farther away to the moon’s left

RACHEL
Spring begins at 11:57 AM on the 20th.

PAUL
This moment in time is called the Vernal Equinox and it’s the moment when the sun stands directly overhead Earth’s equator.

RACHEL
For the last six months, Earth’s southern hemisphere has faced directly towards the sun.

PAUL
That means it’s been spring and summer for our friends in Australia.

RACHEL
Now it’s the northern hemisphere’s chance to enjoy some light and heat from the sun.

PAUL
Want to find Saturn?

RACHEL
Let the moon help you out.

PAUL
Saturn and the moon appear close together on the morning of the 21st.

RACHEL
They actually crossed paths at 8:18 PM on the 20th when the moon occulted Saturn

PAUL
Unfortunately for Idaho, this occurred while they were above the Atlantic Ocean and below our horizon.

RACHEL
Venus reaches its greatest distance from the sun on the morning of the 22nd.

PAUL
However, morning appearances of Venus occurring during March take place at a time when the planet’s orbit is very shallow with respect to the northern hemisphere’s horizon.

RACHEL
So although Venus will appear 46 degrees away from the sun, it’s only seven degrees above the horizon at 5:30 AM.

PAUL
The moon reaches the third quarter phase on the 23rd.

RACHEL
Third quarter is a half full moon, but this time it’s the eastern half that’s in sunlight.

PAUL
Like the first quarter moon, this is an excellent phase for observing the moon

RACHEL
However, you’ll need to go outside after midnight to see the moon.

PAUL
Be sure to focus your attention on the terminator, or boundary between day and night.

RACHEL
Look closely and you may notice there are small points of light on the dark portion of the moon.

PAUL
These will be easier to see through a telescope.

RACHEL
If you do see them, you’ll be seeing high mountain tops or crater peaks where sunrise has occurred hours before it occurs at the surface below.

PAUL
That’s Idaho Skies for the third week of March. Next week you have an opportunity to photograph an attractive pairing of the moon and Venus. 

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, March 9, 2014

Transcript for March 9 - 15

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

PAUL
...and Paul.

RACHEL
There’s a lunar occultation this week.

PAUL
The moon’s joining the occult?

RACHEL
No no, the moon’s covering up a star on the evening of the 10th.

PAUL
As the moon travels in its orbit around Earth, it occasionally passes between us and a star.

RACHEL
Astronomers call this event an occultation.

PAUL
The star is occulting a star in Gemini the Twins called Lambda Geminorum

RACHEL
The moon covers up Lambda along its dark edge.

PAUL
That’s along the right side of the moon.

RACHEL
Use your binoculars and scan along the bottom left of the moon shortly before 7:45 PM.

PAUL
You’ll want to identify Lambda Geminorum several minutes before it’s covered up by the dark edge of the moon.

RACHEL
The moon will cover up the star shortly after 8:00 PM.

PAUL
Because the occultation occurs on the dark edge of the moon, the star will disappear suddenly.

RACHEL
The reappearance of Lambda will be more difficult to observe.

PAUL
That’s because it occurs on the bright edge of the moon.

RACHEL
To observe it, watch the right side of the moon several minutes before 9:18 PM.

PAUL
Lambda reappears near the middle of the bright edge of the moon.

RACHEL
The moon is full on the 16th.

PAUL
The full moon is great for observing its lunar seas and maria.

RACHEL
However, it’s a bad for observing lunar craters and mountains.

PAUL
The one exception is the moon’s dark lunar craters.

RACHEL
These are old craters that became filled with lava.

PAUL
This only occurred in large craters that formed near the time of the moon’s birth.

RACHEL
That’s because craters younger than about 3.5 billion years were created after the moon’s core and mantle had cooled.

PAUL
As a result of the cooler lunar interior, there was no magma or liquid rock below the moon’s surface to fill the depressions created by the impacts.

RACHEL
Through binoculars, two dark craters are very prominent.

PAUL
Near the top of the moon is a 66 miles diameter crater named Plato.

RACHEL
And near the left edge of the moon is a dark crater named Grimaldi.

PAUL
Grimaldi is its 105 miles in diameter, a little bit more than the distance between Boise and Twin Falls.

RACHEL
That’s Idaho Skies for the second week of March. Next week is the first day of spring. 

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.