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.

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.

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.

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.

Transcript for March 2 - 8

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

RACHEL
...and Rachel.

PAUL
This week, let’s talk about the visible planets for March.

RACHEL
Sure, have you seen a bright star above the eastern horizon in the morning as you drive to work?

PAUL
It’s Venus, the Morning Star.

RACHEL
If you haven’t seen it yet, then look for the Morning Star low in the east-southeast.

PAUL
The best time is between 5:30 and 6:00 AM.

RACHEL
If you point a telescope at Venus, you can see that it’s half full.

PAUL
It’s easier to see the phase of Venus if you wait until the sky is brightening.

RACHEL
That’s because Venus is so bright that its glare makes seeing any shape difficult.

PAUL
So wait until the middle of dawn, before the sun rises to observe Venus.

RACHEL
Mars is approaching opposition.

PAUL
Opposition occurs when a planet is opposite the sun in the sky from Earth’s perspective.

RACHEL
So during March, you can expect the planet to continue growing brighter.

PAUL
In fact, we can expect Mars to grow as bright as Sirius, the brightest star in the sky.

RACHEL
However, while Sirius is white, Mars will be noticeably orange-yellow in color.

PAUL
Mars rises at 10 PM by start of month and by sunset at end of month.

RACHEL
To see it, look for it in the east-southeast after dark.

PAUL
Jupiter is high in the south at the beginning of the month.

RACHEL
It’s getting slightly smaller and fainter this month.

PAUL
Why?

RACHEL
That’s because Earth travels much faster around the sun.

PAUL
Oh, so we’re pulling away from Jupiter then.

RACHEL
That’s right and you can’t miss Jupiter, it’s the brilliant yellow-white star high in the west.

PAUL
Saturn, the most distant planet you can see, is visible in the morning skies all during March.

PAUL
It rises after midnight at the beginning of the month and by 10:30 PM at the end of the month.

RACHEL
Look for Saturn low in the east-southeast.

PAUL
It’s the creamy white star and it doesn’t twinkle like the other stars.

RACHEL
For additional help locating it, Saturn is also the brightest star below orange-yellow Mars.

PAUL
That’s Idaho Skies for the first week of March. Next week, you can watch the moon cover up a star.

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.

March's Constellation

This month look for the stars Castor and Pollux, the two brightest stars in Gemini the Twins. Since Castor (Alpha Geminorum) is a little fainter than Pollux (Beta Geminorum), Gemini is one of the few constellations in which the brightest star is not its alpha star. Caster is 52 light-years away and Pollux is 34 light-years away. If you were born in 1962 Castor is your birthday star this year and if you were born in 1980 Pollux is your birthday star this year.

Castor is an interesting star. Through a good telescope, it’s seen as two nearly identical stars with orbital periods of around 400 years. Currently, they are at their closest together with respect to Earth and the gap between them will widen over the coming decades. There’s a third much fainter companion to the south of the main pair that’s a red dwarf star called Castor C. Using spectroscopes, astronomers can detect the light of companion stars around all three stars. Therefore, Castor is reality three double stars in orbit around each other.

Gemini is nearly straight overhead by 8:30 PM at the beginning of March. Use binoculars or a small telescope to look for the galactic cluster M-35 in the right foot of Gemini. The galactic cluster appears as a small sprinkle of stars in binoculars and looks even better through a small telescope.