Idaho Skies Transcript for December 8th, 9th, and 10th

RACHEL
Welcome to Idaho Skies for December 8th, 9th, and 10th. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
What are the best moon phases for stargazers with binoculars?

PAUL
That would be when the moon is half full, or at first and third quarter phases.

RACHEL
Good, the moon stands at third quarter on the night of the 9th and morning of the 10th.

PAUL
Do you know why the moon makes a better binocular target when it’s half full?

RACHEL
Sure. Because when it’s half full, the lunar terminator is directly between the Earth and moon.

PAUL
Remember that the terminator is the boundary between day and night.

RACHEL
And that it marks the location of sunrise and sunset...

PAUL
...or when the shadows cast by the sun stretch their longest across the ground.

RACHEL
Since the terminator is directly between the Earth and moon, the shadows are not foreshortened by the curvature of the moon.

PAUL
The result is long shadows that accentuate small changes in the lunar surface.

RACHEL
This makes it much easier to see features like craters and mountains on the moon, even small ones.

PAUL
Binoculars, with their two inch lens, can make out craters as small as five or six miles across on the moon.

RACHEL
Meaning that over 100 craters are potentially visible through binoculars, especially in the moon’s southern hemisphere.

PAUL
That’s an old region of the moon and it hasn’t been subject to lava flows.

RACHEL
Being old terrain means there’s been lots of time to accumulate craters.

PAUL
And no lava flows means none of these craters have been covered up.

RACHEL
So get your binoculars out on the night of the 9th and morning of the 10th and spend a little quality time with the moon.

PAUL
That’s Idaho Skies for the 8th, 9th, and 10th of December.

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.