Transcript for June 21st to 27th

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

RACHEL
...and Rachel.

PAUL
Hey, summer begins this week.

RACHEL
To be exact, it begins on the 21st at 10:38 AM.

PAUL
The beginning of summer is called a solstice, which means, "to make the sun stand".

RACHEL
"to make the sun stand"?, what does this mean?

PAUL
Well, if you observe sunset, you’ll notice that its position on the horizon shifts every day.

RACHEL
Sure, that’s because Earth’s spin axis is tilted relative to its orbital plane around the sun.

PAUL
That’s right. However, what happens on the first day of summer?

RACHEL
The position of sunset has to stop moving north or else the position of sunset will go completely around the horizon in a full year.

PAUL
Yep. On the first day of summer, the position of sunset appears to stop moving for several days.

RACHEL
Hence, the term to make the sun stand, as in stand still.

PAUL
Here’s how you can find a large star cluster for your binoculars on the night of the 22nd.

RACHEL
After it gets dark, imagine a line up from the moon to Denebola, the bright star above the moon.

PAUL
Then extend that line the same distance above Denebola to a large, but sparse star cluster called Mel-111.

RACHEL
You can see the cluster without binoculars, but only if you observe from outside of town and city lights.

PAUL
You’ll notice that the star cluster becomes more apparent if you look slightly away from the cluster.

RACHEL
This technique of using sideways glances is called averted vision.

PAUL
And it works because the central core of our vision is best at detecting details...

RACHEL
...while the outer perimeter of our vision is more sensitive to faint light and motion.

PAUL
The moon is near the star Spica on the evening of the 25th.

RACHEL
While Spica is not a particularly interesting star for the casual observer, the moon will be in first quarter phase and an interesting target for binoculars and telescopes.

PAUL
So get your binoculars or telescope out and scan along the moon’s boundary between day and night.

RACHEL
You’ll find lots of craters in the southern half of the moon and mountains surrounding lunar seas in the north.

PAUL
One mountain range to look for is the Caucasus Mountains.

RACHEL
It’s the mountain range surrounding part of the Sea of Serenity

PAUL
Which is the lunar sea located in the moon’s upper right corner.

RACHEL
You’ll see the mountains on the left side of Serenity and near the lunar terminator.

PAUL
Some of its peaks are 19,000 feet tall.

RACHEL
That’s a mile taller than Mt. Borah.

PAUL
However, unlike Mt. Borah, lunar quakes didn’t create the Caucasus mountain range over millions of years.

RACHEL
Instead the mountain range was created in a geological flash of time by an impact.

PAUL
The impact was by the asteroid that created the Sea of Serenity.

RACHEL
Along with blasting and vaporizing rock, the impact threw back the lunar crust to form a mountain range.

PAUL
That’s Idaho Skies for the fourth week of June. Did you know there’s a centaur in the sky? Hear about that and three planets next week.

 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.