Idaho Skies Transcript for September 28th and 29th

RACHEL

Welcome to Idaho Skies for September 28^th and 29^th. We’re your hosts, Rachel…

PAUL

…and Paul.

RACHEL

Mercury reaches greatest western elongation on the 28^th.

PAUL

Western elongation occurs when an inferior planet…

RACHEL

…or a planet located between Earth and the sun…

PAUL

…reaches its greatest extent from the sun from Earth’s perspective.

RACHEL

That means the planet appears as far from the sun as possible.

PAUL

If the inclination of the planet’s obit is steep with respect to the horizon, then the planet also appears at its highest point above the horizon also.

RACHEL

Fortunately, the orbits of the planets appear very steep with respect to the horizon in the Autumn.

PAUL

So September is a good month for western elongations.

RACHEL

To find Mercury at its greatest western elongation, go outside on the 28^th at 6:30 AM.

PAUL

Mercury will appear as a reasonable bright white star low in the east.

RACHEL

Binoculars are not needed to see tiny Mercury.

PAUL

Besides, the planet is far too small and distant to show details even through a telescope.

RACHEL

Although, there have been a few sightings of surface details in very special cases.

PAUL

Its largest structure is the Caloris Basin

RACHEL

At 960 miles across, it’s one of the largest impact basins in the solar system.

PAUL

Edging the Caloris basin are mountain ranges thrown up by the impact.

RACHEL

Some of those mountains are 1.2 miles tall.

PAUL

Above Mercury, you’ll also find the very thin crescent moon.

RACHEL

Now use your binoculars and see if your can detect Earthshine.

PAUL

It’s the reflected sunlight illuminating the dark portion of the moon.

  

RACHEL

That’s Idaho Skies for the 28^th and 29^th of September.

PAUL

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

For Idaho Skies this is Paul…

RACHEL

…and Rachel.

PAUL

Dark skies and bright stars.