Transcript for August 4 - 10

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

PAUL
… and Paul.

RACHEL
Our best views of Mercury occur during the first half of the month.

PAUL
That’s because Mercury reached greatest western elongation back on July 30th.

RACHEL
Greatest western elongation occurs when Mercury or Venus reaches its greatest angle away from the sun in the eastern morning sky.

PAUL
Since it just past greatest elongation, Mercury is now approaching closer to the sun.

RACHEL
However, the sun is rising later each morning.

PAUL
That means Mercury’s distance above the horizon prior to sunrise remains nearly unchanged for several days.

RACHEL
Look for Mercury low in the east-northeast for the next two weeks.

PAUL
The moon is just above the star Aldebaran on the morning of the 1st. Many listeners know Aldebaran as the orange eye of Taurus the Bull.

RACHEL
Their separation is just over two degrees, or four lunar diameters. Use your binoculars for observing this pair.

 PAUL
The moon is a waning crescent on the 3rd. This same day, it also makes a close approach to Jupiter.

RACHEL
Jupiter will be obvious as the bright star to the left of the moon. They both will fit within the field of view of your binoculars.

PAUL
On the 4th, the moon passes close to Mars.

RACHEL
Look for them in the low eastern sky in the morning at 5:45 AM.

PAUL
Mars will appear as a yellowish-orange star located to the upper left of the moon.

RACHEL
The very thin crescent moon should display a strong Earthshine.

PAUL
Many people are unfamiliar with Earthshine.

RACHEL
Earthshine is just sunlight reflecting from the moon.

PAUL
However, before the sun’s light reflected off the moon, it first reflected off Earth.

RACHEL
This reflected Earth light faintly illuminates the dark portion of the moon, which is why it is called Earthshine.

PAUL
When you look at the moon, you will see a brightly illuminated crescent surrounding the rest of its faintly illuminated disk.

RACHEL
If you were an astronaut was standing on the Earthshine portion of the moon, it would be dark because the sun had not risen yet.

PAUL
However, overhead would be Earth.

RACHEL
Earth would appear as a nearly full blue-white disk four times larger than the moon appears in our sky and many times brighter.

PAUL
So sunlight reflecting off Earth more brightly illuminates the moon’s surface than the full moon illuminates Earth’s surface.

RACHEL
On the morning of the 8th, Mercury forms a straight line with the stars Castor and Pollux, the brightest stars of Gemini.

PAUL
You’ll need to go outside a little before 6:00 AM and look in the very low east-northeast.

RACHEL
If you go outside much earlier, Mercury will not have risen high enough for you to see.

PAUL
And if you go outside a little after 6:00 AM, the sun will begin brightening the sky too much to see Mercury clearly.

RACHEL
The very thin waxing crescent moon is located five degrees away from Venus on the evening of the 9th.

PAUL
Look low in the west, as the moon is only three days old.

RACHEL
This ought to be an attractive site in your binoculars.

PAUL
That’s Idaho Skies for the first week of August. Next week is one of the year’s best meteor showers.  

RACHEL
Be sure to follow us on Twitter at Idaho Skies for this week’s event reminders and sky maps.

For Idaho Skies this is Rachel…

PAUL
and Paul.

RACHEL
Dark skies and bright stars.