Idaho Skies Transcript for the weekend of January 31st

STEPHEN

Welcome to Idaho Skies for the weekend of January 31^st. We’re your hosts, Stephen…

DAN

…and Dan.

STEPHEN

The moon is at the perfect phase this weekend. That’s the first quarter moon, or when Earth can only see half of the illuminated moon. Remember,  that half of the moon is always experience day. However, this weekend, half of the illuminated side is located on the far side and thus we cannot see it.  

DAN

What makes the first quarter moon so perfect for observing is that the shadows cast by the rising sun appear stretched out to their maximum extent. And those shadows are visible along the lunar terminator.

ARNOLD

I’ll be back

DAN

No, not that kind of terminator. Astronomically speaking, the terminator is the boundary between day and night. And when it’s turned face on to Earth, shadows appear at their greatest angular extent.

STEPHEN

Scan this area with your binoculars or small telescope this weekend. You’ll see mostly craters in the moon’s Southern Hemisphere and lunar seas in the north. Those lunar seas are ringed with mountains where the lunar crust was thrown back by massive impacts billions of years ago.    

DAN

There’s an extra treat on Sunday. That night the moon will be flanked by two star clusters, the Pleiades and the Hyades. The Pleiades is the smaller of the two and it’s a wonderful target for binoculars. The star cluster is 444 light years away. So the Pleiades that you see tonight is what it looked like in 1576.

STEPHEN

That’s Idaho Skies for the weekend of January 31^st.    

DAN

Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com

For Idaho Skies this is Dan…

STEPHEN

…and Stephen.

DAN

Dark skies and bright stars.

Idaho Skies Transcript for the week of January 27th

PAUL

Welcome to Idaho Skies for the week of January 27^th. We’re your hosts, Paul…

STEPHEN

…and Stephen.

PAUL

German astronomer Johannes Hevelius was born on the 28^th in 1611. Since most of our listeners are not familiar with this astronomer, let’s talk about him and his telescopes. Johannes was originally a beer brewer. Then after studying jurisprudence, he settled down in his hometown to become an astronomer. 

STEPHEN

In 1641, Johannes started building telescopes on the roofs of building. Since lens back then were of poor quality, astronomers had to compensate by increasing their focal lengths. For example, one of Johannes’ first long telescopes was twelve feet long. And his telescopes were about to get a lot larger than that.     

PAUL

And by large, we mean large. Johannes eventually made telescopes 60 and 70 feet long. He even built a telescope 150 feet long in 1673. These were called aerial telescopes and they had open tubes. The lenses were held in place with a series of wires. It took a crew to move these telescopes around. 

STEPHEN

Johannes was encouraged to use his telescopes to collect data. Unfortunately, the long and cumbersome telescopes were not a good fit for this. Nonetheless, he did spend four years making lunar maps. They were spectacular for the time and today we still consider Johannes the founder of lunar topography.

PAUL

That’s Idaho Skies for the week of January 27^th.   

STEPHEN

Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Stephen…

PAUL

…and Paul.

STEPHEN

Dark skies and bright stars.

Idaho Skies Transcript for the Weekend of January 17th

STEPHEN

Welcome to Idaho Skies for the weekend of January 17^th. We’re your hosts, Stephen…

DAN

…and Dan.

STEPHEN

The moon reaches third quarter on the 17^th. Late sleepers and early risers will find the half full moon in the east while it’s still dark. Since the moon is half full, the shadows cast by the rising sun strongly accentuate lunar features like craters and mountains. Stargazers with binoculars will want to aim them at the moon on the 17^th.   

DAN

Lunar craters where one time thought to be volcanic in nature. Observations of bullets striking the ground gave no indication that craters could form from impacts. The error was assuming that a “slow” bullet behaved like a meteoroid colliding with the ground at hypersonic speeds.  

STEPHEN

At impact though, a meteoroid vaporizes the ground in the immediate area. Land farther away gets peeled back and then flipped over. This means the closer an astronaut walks to a crater’s rim, the deeper the rock layers originated. Therefore, one need not actually climb down into a crater to get deep rock samples. 

DAN

Many of the craters you’ll see on the moon formed during the late heavy bombardment, or around 3.8 billion years ago. This was a time when planets and moons were sweeping up planetary building blocks. These building blocks are called planetesimals and they condensed from the original gas and dust of the solar system.

STEPHEN

That’s Idaho Skies for the weekend of January 17^th.   

DAN

Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.

For Idaho Skies this is Dan…

STEPHEN

…and Stephen.

DAN

Dark skies and bright stars.

Idaho Skies Transcript for the Week of January 13th

PAUL

Welcome to Idaho Skies for the week of January 13^th. We’re your hosts, Paul…

STEPHEN

…and Stephen.

PAUL

Fifteen years this Tuesday, the Huygens space probe landed on Titan. So let’s talk about Huygens and Titan. But first, the Cassini spacecraft was launched to Saturn back in October 1997. The spacecraft then spent 6.5 years traversing the solar system to reach Saturn. Once there, it fired its thrusters and entered orbit.

STEPHEN

On December 25^th 2004, Cassini released the Huygens probe. Huygens was riding piggy-back on the spacecraft and didn’t carry its own set of thrusters. This means Cassini had to aim for Titan before the release and then fire its thrusters afterwards to miss Titan. Titan by the way is Saturn’s largest moon.

PAUL

What makes Titan so special and interesting is that it has a dense atmosphere. In fact, it’s 50% denser than our atmosphere. Like our atmosphere, Titan’s is mostly nitrogen. Unlike ours, Titan’s atmosphere has no oxygen and its freezing cold. On its surface, the temperature is -290 degrees Fahrenheit.  

STEPHEN

Huygens returned images of an icy landscape of hills, dunes, and drainage patterns. Since Titan’s surface is bitterly cold, water ice is as hard as granite. Methane, a gas also on Earth, is a liquid on Titan. The moon therefore has a geological cycle of water and a hydrological cycle of methane. Still, Huygens returned landscape images looking very similar to Earth. 

PAUL

That’s Idaho Skies for the week of January 13^th.  

STEPHEN

Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Stephen…

PAUL

…and Paul.

STEPHEN

Dark skies and bright stars.

Idaho Skies Transcript for the Weekend of January 10th

STEPHEN

Welcome to Idaho Skies for the weekend of January 10^th. We’re your hosts, Stephen…

PAUL

…and Paul.

STEPHEN

Hey, the moon is full on the 10^th. Did you know that some Native American tribes named the first full moon of January the Wolf Moon? They did because on cold winter nights, wolves are hungrier than usual. So the people of these cultures would hear wolves howling more frequently at night.

PAUL

The full moon illuminates the sky and washes away all the fainter stars. That means the nights near the full moon are bad times to look for faint and fuzzy astronomical objects like comets and nebulae. Therefore, check out the sky tonight and see how the moon’s light changes the sky from dark black to grayish blue.  

STEPHEN

Then get out your binoculars for the night of the 11^th. The Beehive star cluster will be three degrees to the upper right of the moon. Since binoculars have a field of view of 7.5 degrees, both the moon and star cluster will appear together. However, it will be better if you shift the moon out of the field of view.

PAUL

The Beehive star cluster appears as large as the moon, so it’s not very small. You’ll see a compact groping of some two dozen stars, once the moon is out of sight. People call this star cluster the Beehive because it has a strong resemblance to bees buzzing around their hive. Do you see the same thing?   

STEPEN

That’s Idaho Skies for the weekend of January 10^th.

PAUL

Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.

For Idaho Skies this is Paul…

STEPHEN

…and Stephen.

PAUL

Dark skies and bright stars.

Idaho Skies Transcript for the Week of January 6th

DAN

Welcome to Idaho Skies for the week of January 6^th. We’re your hosts, Dan…

PAUL

…and Paul.

DAN

Earth just passed perihelion this week. So let’s discuss perihelion and what it means for Earth. Perihelion is that point in an elliptical orbit that is closest to the sun. At perihelion, Earth is only 91 million, 343 thousand miles from the sun. Or about 2% closer than average.

PAUL

Even though Earth receives about 7% more sunlight at perihelion, it occurs over the Southern Hemisphere. The Southern Hemisphere, which is covered mostly by water, is difficult to warm up. Therefore, all that extra sunlight can’t warm air temperatures in the Southern Hemisphere very significantly.  

DAN

On the 7^th, stargazers will find the waxing gibbous moon near the eye of the celestial bull. That bull is named Taurus and his eye is named Aldebaran. Taurus is an old constellation. In fact, this pattern of stars was recognized as a bull all the way back to the Bronze Age, over 6,000 years ago.    

PAUL

The distance between the moon and Aldebaran is five degrees. Since binoculars have a field of view of around 7.5 degrees, the moon and Aldebaran will be seen together. But notice that Aldebaran has company. To the right of Aldebaran and a little above are the stars of the Hyades star cluster.

DAN

That’s Idaho Skies for the week of January 6^th.  

PAUL

Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Paul…

DAN

…and Dan.

PAUL

Dark skies and bright stars.