Idaho Skies Transcript for the weekend of December 20th

STEPHEN

Welcome to Idaho Skies for the weekend of December 20^th. We’re your hosts, Stephen…

DAN

…and Dan.

STEPHEN

Astronomically speaking, winter begins on the 21^st at 9:19 PM. At that time, the sun appears its farthest south of Earth’s equator. With the sun that low in our sky, the days are their shortest and the sun’s light its most spread out. The combination of low sunlight intensity, short days, and long nights make our winter weather very cold.

DAN

The sun’s position in the sky drifts north during the winter and spring and then south during summer and autumn. When the sun reaches its northerly or southerly extreme, astronomers call it a solstice. The word solstice means sun standing still because on those days, the sun’s movement north and south appears to halt for a few days. 

STEPHEN

At 6:00 AM the morning after the winter solstice, stargazers will find the moon seven degrees above Mars. Seven degrees is a little less than the width of your fist when viewed at the end of your outstretched arm. Mars won’t be very bright since is 209 million miles. That’s just too far away for the reflected light of such a small planet.  

DAN

Slightly fainter and closer to the moon’s left is a star named Zubenelgenubi. That’s a funny sounding name for a star that’s really a pair of stars. Good binoculars can split this star into two. Some people in fact may have good enough vision that they can split it without optical aid. Are you one?

STEPHEN

Not me.

That’s Idaho Skies for the weekend of December 20^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 December 16th

PAUL

Welcome to Idaho Skies for the week of December 16^th. We’re your hosts, Paul…

STEPHEN

…and Stephen.

PAUL

This week marks the beginning of the Ursid meteor shower. Haven’t hear of it? Well, not many people have. It’s a weak shower that only produces ten meteors per hour on average. Its parent body is comet Tuttle. And as this comet approaches the sun, the sun’s heat vaporizes the comet’s surface to release fine dust that can becomes meteors.

STEPHEN

Astronomers know that the Ursids can produce over 100 meteors per hour on occasion. That’s because the gravitational pull of Jupiter concentrates the meteor stream in places. When this is going to occur, astronomers can’t accurately predict. Therefore, it might be worth your while to look for this meteor shower occasionally this week. 

PAUL

Listeners observing this shower need to identify meteors originating from the north. Specifically, from the brightest star in the bowl of the Little Dipper. That star’s name is Kochab. Kochab is slightly fainter than its more famous brethren, Polaris on the other end of the Little Dipper.   

STEPHEN

On the morning of the 17^th, stargazers will find the nearly third quarter moon close to the star Regulus. That’s the brightest star in Leo the Lion. Then late on the night of the 18^th, you can use your binoculars to observe the craters long the terminator of the half full moon. So there are two lunar events that you can enjoy this week.

PAUL

That’s Idaho Skies for the week of December 16^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 December 13th

BENJAMIN

Welcome to Idaho Skies for the weekend of December 13^th. We’re your hosts, Benjamin…

PAUL

…and Paul.

BENJAMIN

The moon visits Pollux, one of the Gemini Twins on the 13^th. Twin brother Pollux is the row of stars on the left and right sides of the moon. Its brightest star, also named Pollux, is on the left and it represents the head of this celestial brother. In the Gemini myth, Pollux is the immortal brother of the two. 

PAUL

This weekend, the Geminid meteor shower reaches its peak intensity. Stargazers can normally expect to see upwards of 100 meteors per hour from this shower. The meteoroids of this shower travel so fast that they create white-hot shock waves. So that meteor streak you see is really the thin atmosphere glowing white hot from the passage of the meteoroid.  

BENJAMIN

Unfortunately, the nearly full moon rises in Gemini. That’s the same constellation that the Geminid meteor shower originates from. Therefore, strong moon light will out-shine most of the meteors of this shower. Your best bet to see Geminids therefore is to look for them overhead and not in the east where the moon is located.

PAUL

On Sunday night, you’ll find the moon a short distance from the Beehive star cluster. So get your binoculars out and aim them at the moon. Then shift them downwards until the moon leaves the view at the 1 o’clock position. At the bottom of your view will be a cluster of over a dozen tightly packed stars.

BENJAMIN

That’s Idaho Skies for the weekend of December 13^th.

PAUL

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

For Idaho Skies this is Paul…

BENJAMIN

…and Benjamin.

PAUL

Dark skies and bright stars.

Idaho Skies Transcript for the week of December 9th

DAN

Welcome to Idaho Skies for the week of December 9^th. We’re your hosts, Dan…

BENJAMIN

…and Dan.

DAN

Because it travels around the heavens in 30 days, the moon makes a great astronomical guide. However, it’s restricted to the path taken by the sun and planets, or the constellations of the Zodiac. Since the Pleiades and Hyades star clusters are located in Taurus the Bull, the moon visits them monthly. 

BENJAMIN

So go outside on the 9^th to locate the Pleiades above the moon. Then again on the 10^th to find the moon inside the Hyades star cluster. Both star clusters are ideal binocular objects. As long as the moon’s light doesn’t interfere with the fainter stars, you’ll see at least two dozen stars in each cluster.   

DAN

Moonlight is a problem, however, because the moon is full on the 11^th. The full moon can be blinding through a telescope or even binoculars. After looking at the moon, don’t be surprised if you can’t see faint objects as well as you could before. Fortunately, this effect goes away in a few minutes.

BENJAMIN

You will hardly see any craters on the full moon. There are two reasons for this. First, when the sun is overhead, it casts few shadows. And two, Earth and the sun appear in the same place from the moon’s perspective. That means any shadows cast by sunlight are covered up by the terrain creating the shadows in the first place.      

DAN

That’s Idaho Skies for the week of December 9^th.  

BEJAMIN

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

For Idaho Skies this is Benjamin…

DAN

…and Dan.

BENJAMIN

Dark skies and bright stars.

Idaho Skies Transcript for the weekend of December 6th

STEPHEN

Welcome to Idaho Skies for the weekend of December 6^th. We’re your hosts, Stephen…

DAN

…and Dan.

STEPHEN

On the 8^th, Comet Borisov reaches perihelion. So let’s talk about perihelion and Comet Borisov. The word perihelion comes from the Greek “peri” and that’s the prefix meaning “about” or “around”. Think of the word perimeter as an example. And the word Helion comes from the word Helios, which is the Greek name for the sun.     

DAN

Perihelion can only occur for objects that travel in non-circular orbits. That means at perihelion, objects like Comet Borisov pass their closest to the sun. However, Comet Borisov has an orbit that’s a bit odd - it’s hyperbolic and not elliptical in shape. That means the orbit of Borisov doesn’t begin nor end in our solar system. 

STEPHEN

Comet Borisov is traveling so fast that it will escape our solar system. It didn’t pick up this speed from a close pass to another planet in our solar system. Instead, it’s traveling so fast because it escaped from another star system and fell into ours. The gravity of another object in its original solar system must have kicked it into interstellar space. 

DAN

Astronomers predict that there’s at least one interstellar visitor in our solar system at any given time. They approach the sun in a hyperbolic orbit and then fly away to never be seen again. Currently, visits by interstellar objects are the best way we can study the materials and formation of other solar systems.

STEPHEN

That’s Idaho Skies for the weekend of December 6^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 December 2nd

PAUL

Welcome to Idaho Skies for the week of December 2^nd. We’re your hosts, Paul

STEPHEN

…and Stephen.

PAUL

It’s easy to be a rock star when there are no bright stars near you. And that’s definitely true for Fomalhaut, the star below the moon on the 3^rd. Astronomers rate Fomalhaut as first magnitude. It was the ancient Greeks who designed this magnitude system as a way to classify stars by their apparent brightness.

STEPHEN

They designed the magnitude system to start with a one for the brightest stars and six for the faintest the unaided eye can see. There are 17 stars brighter than Fomalhaut and some of them have negative magnitudes. For example, Sirius, the bright star rising at 9:45 PM this evening is magnitude is -1.5.   

PAUL

The moon reaches first quarter minutes before midnight of the 4^th. That means it looks so close to first quarter on the 3^rd that you won’t see the difference. First quarter occurs when the angle between the sun, Earth, and moon is 90 degrees. So the moon is nearly due south as the sun sets in the southwest.

STEPHEN

Recall that the sun always illuminates exactly half of the moon. Therefore, at first quarter we can only see half of the illuminated lunar surface. Lunar seas or lava plains cover much of the northern half that we can see and craters fill the southern half. This makes the first quarter phase the perfect moon for exploring with binoculars.   

PAUL

That’s Idaho Skies for the week of December 2^nd.  

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.