The science

EXPERIENCE THE SHADOW OF THE MOON!

On Monday, August 21, 2017 the shadow of the moon will pass across the US making a line from Oregon to South Carolina.  It is estimated that 50 million people will be able to witness “totality” for a few minutes as the moon completely blocks the sun.  While Western New Yorkers will only be able to witness a partial eclipse, it will still be remarkable as about 75% of the sun will be obscured by the moon.  August 21, 2017 is going to be a BIG deal, and we want to help you experience it.

This guide was put together by several organizations in Western New York that do outreach programming for astronomy.  We want you to be able to make the most of this spectacular event, whether that is travelling to witness totality, or viewing the partial eclipse from home. We will be hosting opportunities to learn about and prepare for the eclipse beforehand at one of WNY’s planetariums.

WHAT IS A SOLAR ECLIPSE?

A solar eclipse happens when the moon, as seen by us on Earth, passes directly in front of the sun.  Once each month, the moon makes a complete orbit (or revolution) around the Earth.  The changing angle of sunlight on the moon causes the waxing and waning of the moon’s phases.  At new moon, it is not visible because the side facing Earth is not lit by the sun.  Furthermore, it is lost in the glare of the sun as it passes between the sun and Earth.  Due to the tilt of the moon’s orbit, it normally passes just above or below the sun.  However, every 6 months the alignment is just right and the moon can pass directly in front of the sun.

Even though the sun is much larger than the moon, the two bodies are at just the right distances to make them appear to be the same size in our sky.  This means that the bright yellow disk of the sun, known as the photosphere, can be blocked revealing the sun’s atmosphere which is called the corona.  When this happens, a beautiful ring of light appears, the stars are visible in the middle of the day, birds stop chirping because they think it is night time, and people experience a few minutes of eerie “totality” darkness in the middle of the day.

totality
Filtered lens view of totality.

MOON SHADOWS

There are two parts of the moon’s shadow.  The area where all of the sun is blocked is called the “umbra” and the area where only part of the sun is blocked is called the “penumbra.”  To experience “totality”, you will have to be along a narrow line where the moon’s umbra sweeps across the Earth.  If you are in the penumbra, you will only see a partial eclipse as is the case in Buffalo for this eclipse.

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partial-eclipse

LEARN MUCH MORE ABOUT THE ECLIPSE AT A PLANETARIUM