Transcript of the Fourth Week of April

RACHEL
Welcome to Idaho Skies for the last week of April. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
Spica, the brightest star in Virgo, is two degrees above the moon on the evening of the 24th.

PAUL
For a sense of perspective, two degrees is approximately the width of your thumb when you fully extend your arm.

RACHEL
Spica will appear so close to the moon that you can see both together in your binoculars.

PAUL
Speaking of the moon, the moon is full on the 25th.

RACHEL
The full moon in April is often called the Egg Moon.

PAUL
When the moon is full, you’ll notice that the moon’s light renders the fainter stars invisible. In hazy or humid air, the full moon can turn the night sky a shade of light blue.

RACHEL
Although the full moon appears bright, it only reflects 12% of the sunlight shining on it.

PAUL
Astronomers use the term albedeo to describe the reflectivity of astronomical objects.

RACHEL
Albedo is a number between 0 and 1. An albedo of zero is not reflective at all and an albedo of 1 is 100% reflective.

PAUL
The moon’s albedo is about 0.12 or equal to the albedo of old asphalt.

RACHEL
Earth’s albedo on the other hand is 0.37, which means our planet reflects 37% of the sunlight shining on it.

PAUL
Can you locate Saturn in the night sky?

RACHEL
Saturn is right above the full moon on the 25th.

PAUL
Saturn will appear as a pale yellow-white star.

RACHEL
Unlike most stars however, Saturn will not twinkle.

PAUL
You need a telescope in order to see the planet’s rings; binoculars are not powerful enough.

RACHEL
Saturn and the moon rise by nine PM. So wait until at least 9:30 to look for Saturn.

PAUL
Three nights later Saturn reaches opposition.

RACHEL
That means on the 28th, Saturn is located directly opposite the sun in our sky.

PAUL
This also means that Saturn is closest to Earth.

RACHEL
At a distance of 860 million miles, the light you see from Saturn spent an hour and 17 minutes traversing the vacuum of outer space to reach your eye.

PAUL
A car driving at 70 miles per hour would need 1,400 years to reach Saturn at opposition.

RACHEL
That’s Idaho Skies for the last week of April. Listen next month for the astronomical events occurring in Idaho.

PAUL
Be sure to read our blog for additional information. It’s at idahoskies dot blogspot dot com For Idaho Skies this is Paul…

RACHEL
and Rachel.

PAUL
Dark skies and bright stars.