Transcript for April 26 to May 2

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

RACHEL
...and Rachel.

PAUL
Let’s compare two stars that the will moon pass this week.

RACHEL
The first is Regulus.

PAUL
The moon passes just below Regulus on the night of the 27th.

RACHEL
And the second star is Spica.

PAUL
The moon passes just above Spica on the night of May 1st.

RACHEL
Spica appears just a bit brighter than Regulus, but not by much.

PAUL
Astronomers call Regulus and Spica B class stars.

RACHEL
This is the second highest class and therefore second hottest category of stars.

PAUL
Both appear as blue-white stars because of their exceeding high surface temperatures.

RACHEL
And we mean hot, these stars have surface temperatures twice as high as the sun.

PAUL
Cooler stars like the sun generate energy by fusing hydrogen straight into helium.

RACHEL
However, hotter B class stars use carbon and oxygen as a catalyst to fuse their hydrogen into helium.

PAUL
This hotter fusion process is possible because these stars are much more massive than the sun.

RACHEL
Regulus is four times more massive and Spica is ten times more massive.

PAUL
That extra mass and increased fusion rate makes Regulus nearly 300 times brighter than the sun.

RACHEL
And it makes Spica over 10,000 times brighter.

PAUL
The reason Regulus looks nearly equal to much brighter Spica is that Spica is three times farther away from Earth than Regulus.

RACHEL
After you find Spica below the moon on the 1st, turn your attention to a location below and to the right of Spica.

PAUL
You’re looking for a squashed square of four stars.

RACHEL
These stars are a constellation called Corvus.

PAUL
Corvus is a Crow.

RACHEL
It was one of the original 48 constellations described by Ptolemy back in the second century AD.

PAUL
And it’s one of the smallest of the official 88 astronomical constellations.

RACHEL
So how did a crow become a constellation?

PAUL
According one legend, the Greek god Apollo threw a crow into the heavens after it made him angry.

RACHEL
How does a crow make a god angry?

PAUL
By being late returning a cup of water as asked.

RACHEL
In a fit of rage, Apollo threw Corvus and the cup into the heavens.

PAUL
And let that be a lesson for us all.

RACHEL
That’s Idaho Skies for the last week of April. 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 April 19 to 25

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

PAUL
 ...and Paul.

 RACHEL
Like all stars, Aldebaran, the alpha star of Taurus the Bull is moving closer to the western horizon every night. 

PAUL
Since Venus is a planet, it’s moving away from the horizon every night.

RACHEL
That is at least until June when Venus begins passing between Earth and the sun.

PAUL
Therefore, it’s not surprising to hear that these two celestial objects cross paths on occasion. 

RACHEL
You’ll find Venus on the outskirts of the Hyades star cluster and therefore close to Aldebaran on the evening of the 20th.

PAUL
When you go out to see them, be sure to look for the young and very thin crescent moon close to the horizon.

RACHEL
Two days later, Aldebaran, the moon, the Pleiades, and Venus form a compact grouping.

PAUL
The grouping is so small that you can just about cover them with your outstretched hand on the 21st. 

RACHEL
That’s a bunch of binocular objects for the choosing and you don’t have to scan the rest of the sky to see them.

PAUL
Mercury has traveled its greatest distance away from the sun and is now inching its way back. 

RACHEL
Before long, it will be too close to the horizon and sun to be visible in the evening.

PAUL
On its way back to the sun, the innermost planet passes close to Mars on the 22nd.

RACHEL
Mercury is brighter than Mercury, so you can’t confuse them.

PAUL
At 8:30 PM on the 22nd, scan the sky close to the horizon and to the lower right of Venus.

RACHEL
The first star you’ll find is Mercury.

PAUL
Mars will be the fainter star located to the lower left of Mercury.

RACHEL
It’s been three months since we’ve had the opportunity to watch a meteor shower and quite frankly, we’re overdue.

PAUL
During the last week of April, the Lyrid meteor shower picks up its level of activity.

RACHEL The meteor shower reaches its peak activity on the night of the 22nd and morning of the 23rd.

PAUL
Meteors from this shower will appear to originate from the northeast and become more numerous after midnight.

RACHEL
Fortunately, this year the moon is a thin crescent on the 22nd and it therefore sets before midnight. 

PAUL
On the down side, this is not one of the best meteor showers of the year.

RACHEL
You can only expect to see some ten meteors per hour from this shower.

PAUL
But hey, since our last meteor shower occurred in January, the Lyrids aren’t bad.

RACHEL
The Beehive star cluster is one of the nicest star clusters for binocular viewing.

PAUL
This star cluster is easy to see, but it’s located in a rather blank part of the sky.

RACHEL
So it’s really helpful to have the moon show you its location.

PAUL
On the 25th, scan straight up along the moon’s terminator or the boundary between lunar day and night, until you run into the cluster.

RACHEL
The star cluster will look like a sprinkling of diamond dust in your binoculars.

PAUL There’s another, smaller star cluster nearby called M-67.

RACHEL
And you’ll be able to find this star cluster by keeping in mind that Jupiter, M-67, the moon, and the Beehive star cluster form a square.

PAUL
That’s Idaho Skies for the fourth week of April. Next week we’ll compare two blue-white stars that the moon passes.

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 April 12 - 18

RACHEL Welcome to Idaho Skies for the third week of April. We’re your hosts, Rachel... PAUL ...and Paul. RACHEL The first human to travel into space did so on April 12th, 1961. PAUL His name was Yuri Gagarin and he was a 27 year old pilot of the Soviet Air Force. RACHEL This came as a bit of a surprise to the United States, which was planning to launch American astronauts during Project Mercury. PAUL In fact, if it hadn’t been for concerns about earlier Redstone tests and bad weather, we might have beaten the Soviets and put the first man into space. RACHEL However, Yuri’s flight was significantly different from the first two American flights. PAUL That’s because Yuri actually made one orbit around Earth before returning in his Vostok space capsule. RACHEL The United States launched its first two astronauts using converted Redstone missiles. PAUL And these missiles didn’t have the power to place a Mercury space capsule into orbit. RACHEL That’s why the first two American astronauts were only lobbed 115 miles up before descending back to the Atlantic Ocean. PAUL The reason the Soviets were able to put Yuri into orbit is that their R-7 missile was much larger and powerful than the Redstone. RACHEL Because of concerns they might fail, the Soviets didn’t announce Yuri’s mission until 52 minutes into his flight. PAUL And less than 40 minutes later, he had fired his retro rockets and was returning back to Earth. RACHEL The Mercury capsules returned to Earth by splashing down into the ocean, however the Vostok 1 landed on the ground. PAUL This made for a much harder landing. RACHEL In order to protect their cosmonaut, Yuri was ejected out of the capsule as it neared the ground. PAUL That allowed Yuri to land softly on his own parachute and separate from his capsule. RACHEL Because of his propaganda importance to the Soviet Union, Yuri was never allowed to travel back into space. PAUL The moon takes it time approaching the eastern horizon starting on the 14th. RACHEL That’s because its approach to the sun is very shallow. PAUL This always happens during the spring. RACHEL Contrast this to the autumn when the moon’s approach to the horizon more vertical. PAUL So as a consequence, you have more opportunities to observe Earthshine during spring mornings. RACHEL Look for the moon in the low east-southeast as you drive to work. PAUL Earthshine will appear on the right side of the moon. RACHEL That’s Idaho Skies for the third week of April. Next week marks the end of our drought of meteor showers. 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.

Merak is this Month's Star

This month look for the star Merak in Ursa Major. The popular name of Ursa Major is the Big Dipper. Actually, the Big Dipper is an asterism, or familiar pattern of stars and not a constellation. The Big Dipper asterism represents a bear’s hind quarters and extremely long tail. The rest of the bear consists of fainter stars, which gives Ursa Major its ursine shape. The constellation’s name means Great Bear in Latin.

Astronomers call Merak Beta Ursae Majoris. In Arabic, Merak means “flank of the bear”. Merak is a star larger star than our sun; it’s three times more massive and 60 times brighter. Its extra mass squeezes the star’s core with such great force that it’s fusing its hydrogen fuel faster than does the sun. Merak’s greater fusion rate makes it a white hot star with a surface temperature of over 15,000 degrees. Merak is 79 light years away, so the light you see tonight left the star in 1936.

You’ll find Merak and Ursa Major high overhead after it gets dark in April. The dipper is upside down and appears to be pouring the water in its bowl into the Little Dipper.

Transcript for April 5 - 11

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

RACHEL
...and Rachel.

PAUL
Looking for Saturn?

RACHEL
Then look no further than the moon on the morning of the 8th.

PAUL
Saturn is the cream-colored star below the moon.

RACHEL
Saturn shows its rings through a small telescope or spotting scope.

PAUL
But not in most binoculars.

RACHEL
A magnification of as little as 25 power is enough to see its rings and brightest satellite, Titan.

PAUL
In a telescope, Titan will appear as the star to the upper right of Saturn.

RACHEL
Titan is a wonderful satellite by itself.

PAUL
It’s 50% larger than Earth’s moon.

RACHEL
And it has an atmosphere 50% greater than Earth’s atmosphere.

PAUL
Below its icy surface may be a deep liquid ocean.

RACHEL
Jupiter is approaching the Beehive star cluster because it’s retrograding.

PAUL
Retrograding? What’s that, some kind of 70’s fashion?

RACHEL
Retrograde motion occurs when Earth’s motion begins to overtake the orbital motion of a more distant planet like Jupiter.

PAUL
So during retrograde, outer planets travel from east to west across the sky, rather then the normal west to east.

RACHEL
On the evening of the 8th, Jupiter reaches the end of its retrograde motion and is at its closest to the Beehive star cluster.

PAUL
The pair is so close together that you can see both at the same time in binoculars.

RACHEL
If you point your binoculars at Jupiter on the 8th, place it on the left edge of your binocular’s view.

PAUL
That way the Beehive star cluster will pop out on the right side.

RACHEL
Then take a closer look at Jupiter to see largest satellite, Ganymede on the right side of Jupiter.

PAUL
When you see Ganymede, you’re looking at the largest satellite in the solar system.

RACHEL
It’s a giant moon that’s larger than the planet Mercury.

PAUL
And as the Hubble Space Telescope recently discovered, it most likely contains a vast ocean beneath its icy exterior.

RACHEL
In fact, there may be more liquid water beneath Ganymede than on Earth.

PAUL
Venus is climbing higher above the horizon every night while the Pleiades star cluster is descending lower.

RACHEL
The two meet up on the evenings of the 10th and 11th when they will be less than three degrees apart

PAUL
That puts them so close together that you can enjoy both at the same time in a pair of binoculars.

RACHEL
The Pleiades are located to the upper right of Venus.

PAUL
Look for the pair in the low west at around 9:30 PM.

RACHEL
You won’t be able to miss brilliant Venus.

PAUL
That’s Idaho Skies for the second week of April. Next week we celebrate a space-age anniversary that took place 54 years ago.

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.