Thursday, March 19, 2009

Ain't We Got Fun

Every morning
Every evening
Ain't we got fun…

Every eight years, planet Venus is positioned such that we Northern Hemisphere dwellers can see it at both dawn and dusk— on the same day! That time has come.

On March 22nd, 23rd, and 24th, you will have a chance to see Venus as both Morning Star and Evening Star.

To observe this phenomenon, pick an observing location with unobstructed views of the eastern and western horizons. In the morning, shortly before sunrise, look ENE for the brilliant planet, low over the horizon. It will be north of where the Sun rises. Do not look directly at the Sun after it rises, as this will damage your eyes!

In the evening, just after sunset, look WNW for the goddess of love, low over the horizon and north of where the Sun sets.

Start looking on the 22nd, just in case clouds or foul weather eliminate your view at either dawn or dusk. The goal here is to see Venus twice in one day.

Venus in crescent phase (NASA)

If you have binoculars or a telescope, and you’re careful to catch Venus before the Sun rises or after it sets, look for the ultra-thin crescent phase that Venus is currently exhibiting. You can also look for the cusp extensions that may be visible; sunlight scattered by Venus’s atmosphere makes the ends of the thin crescent appear to stretch more than halfway around the limb (outer edge) of the planet’s disk!

If you’re successful with your double observation, post a comment here and claim your bragging rights!

Night or day-time
It's all play-time
Ain't we got fun?

Astronomy Essential: All solar system bodies except the Sun shine by reflected light.

Earth, our Moon, the other planets and their moons, the asteroids, and the comets of our solar system appear illuminated because they reflect sunlight, not because they are producing light. However, stars— of which our Sun is one— are themselves light sources.

Reflection is the rebounding of light from a surface.