Transcript for March 9 - 15

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

PAUL
...and Paul.

RACHEL
There’s a lunar occultation this week.

PAUL
The moon’s joining the occult?

RACHEL
No no, the moon’s covering up a star on the evening of the 10th.

PAUL
As the moon travels in its orbit around Earth, it occasionally passes between us and a star.

RACHEL
Astronomers call this event an occultation.

PAUL
The star is occulting a star in Gemini the Twins called Lambda Geminorum

RACHEL
The moon covers up Lambda along its dark edge.

PAUL
That’s along the right side of the moon.

RACHEL
Use your binoculars and scan along the bottom left of the moon shortly before 7:45 PM.

PAUL
You’ll want to identify Lambda Geminorum several minutes before it’s covered up by the dark edge of the moon.

RACHEL
The moon will cover up the star shortly after 8:00 PM.

PAUL
Because the occultation occurs on the dark edge of the moon, the star will disappear suddenly.

RACHEL
The reappearance of Lambda will be more difficult to observe.

PAUL
That’s because it occurs on the bright edge of the moon.

RACHEL
To observe it, watch the right side of the moon several minutes before 9:18 PM.

PAUL
Lambda reappears near the middle of the bright edge of the moon.

RACHEL
The moon is full on the 16th.

PAUL
The full moon is great for observing its lunar seas and maria.

RACHEL
However, it’s a bad for observing lunar craters and mountains.

PAUL
The one exception is the moon’s dark lunar craters.

RACHEL
These are old craters that became filled with lava.

PAUL
This only occurred in large craters that formed near the time of the moon’s birth.

RACHEL
That’s because craters younger than about 3.5 billion years were created after the moon’s core and mantle had cooled.

PAUL
As a result of the cooler lunar interior, there was no magma or liquid rock below the moon’s surface to fill the depressions created by the impacts.

RACHEL
Through binoculars, two dark craters are very prominent.

PAUL
Near the top of the moon is a 66 miles diameter crater named Plato.

RACHEL
And near the left edge of the moon is a dark crater named Grimaldi.

PAUL
Grimaldi is its 105 miles in diameter, a little bit more than the distance between Boise and Twin Falls.

RACHEL
That’s Idaho Skies for the second week of March. Next week is the first day of spring. 

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.