Idaho Skies Transcript for May 21st and 22nd

RACHEL
Welcome to Idaho Skies for May 21st and 22nd. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
There’s a close encounter in the evening sky on the 21st.

PAUL
But it’s an astronomical close encounter and not the extraterrestrial type.

RACHEL
Stargazers going outside early on the night of the 21st will see a star very close to the moon.

PAUL
That star is Regulus, which represents the heart of Leo the Lion.

RACHEL
Regulus is also the brightest star of Leo.

PAUL
You might want to get your binoculars out for this one.

RACHEL
That’s because Regulus is on the right side, or the illuminated half of the moon.

PAUL
So the glare will be a little bit on the strong side.

RACHEL
Unfortunately, the moon will not cover up or occult Regulus.

PAUL
Although this does happen during some months.

RACHEL
One reason that the moon doesn’t occult Regulus every month is that the moon’s orbit around Earth is tilted 

PAUL
By 5 degrees compared Earth’s orbital plane around the sun, in fact.

RACHEL
That still doesn’t explain why the moon occults Regulus some years and not others.

PAUL
The reason for the variation is that the lunar orbital tilt spins in space.

RACHEL
So like a spinning top about to fall over, the direction that the lunar orbit’s tilt is leaning changes over time.

PAUL
In fact, in a cycle lasting 19 years.

RACHEL
And there are other astronomical motions to make things even more complicated.

PAUL
Combined together, they create irregular patterns to the occultation of Regulus.

RACHEL
That’s Idaho Skies for the 21st and 22nd of May.

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

For Idaho Skies this is Paul…

RACHEL
…and Rachel.

PAUL
Dark skies and bright stars.