Astro Mark: Make sure to catch the full lunar eclipse Sunday |

Astro Mark: Make sure to catch the full lunar eclipse Sunday

The shadow of Earth casts a red hue on the moon during a lunar eclipse.
Getty Images

A full lunar eclipse on May 15th — that’s amore!

You’ve heard the lyrics to that Italian song: “When the moon fills the sky, like a big pizza pie, that’s amore!” Of course you have. This Sunday, May 15, the moon will be that big pizza pie as the cosmos serves you up a slice of celestial goodness. Yum.

The Ingredients for a great lunar eclipse pizza

An eclipse begins with a line. Remember, a line is made up of a set of points which is extended in opposite directions. In astronomy speak this is called “syzygy” — a rough straight-line configuration of three, or more, celestial bodies in a gravitational system.

You want to know more? In a lunar eclipse, those set points are the sun, the Earth, and the moon. As the Earth passes between the sun and the moon, it casts a shadow on the moon. But, since the moon’s orbit is tipped about 5 degrees in relation to the Earth and sun, that straight line isn’t entirely straight. A lunar eclipse is the result of the moon crossing that plane of the Earth and sun at the same time of a full moon.

There are three types of lunar eclipses:

  • Penumbral eclipse — when the moon passes through the Earth’s penumbral shadow.
  • Partial eclipse — when the moon only partially enters the Earth’s umbral shadow.
  • Total Eclipse — when the entire Moon passes through the Earth’s umbral shadow.

What makes this big pizza of an eclipse so special?

This total lunar eclipse just happens to be near the time when the moon is closest to Earth in its elliptical orbit. This point is called the “perigee” of an orbit. A full moon at perigee is often called a “supermoon.” So here we have a “perigee-syzygy.” Whoa! That’s a lot to take in. If you need to sit down to catch your breath, that’s fine. Not to worry, this eclipse from start to finish will last 5 hours and 20 minutes, so you have time to recover.

Here are the times and events of the May 15 eclipse:

  • 7:33 p.m. — the moon enters the Earth’s penumbra
  • 8:28 p.m. — the moon begins partial eclipse
  • 9:30 p.m. — the moon begins totality
  • 10:54 p.m. — the moon ends totality
  • 11:55 p.m. — the moon ends partial eclipse
  • 12:51 a.m. on May 16 — the moon departs the Earth’s penumbra

What to look for

As the Moon enters the outer region of the Earth’s shadow called the penumbra, it is already inside the Earth’s shadow, yet it appears to cover just part of the moon’s disk.

During the partial phase of the eclipse, look for the curved shape of the Earth’s shadow as it moves across the moon. When it enters the umbra nearing totality, around 10:12 p.m., the color of the moon’s surface and the rim is breathtaking. The moon’s face can be a rusty brick red while the rim of the disk can be a bright orange. This coloring is due to both atmospheric particulates — dust, ash, sand — and to Rayleigh scattering. This scattering effect happens when sunlight is refracted and scattered by the Earth’s atmosphere. The result is that the longer, red wavelengths are bent and directed towards the shadow cone and onto the moon’s surface. Don’t be surprised if you see the same red sauce color of your favorite pizza pie. And get out your binoculars or telescope to take an even bigger bite of color, appearance and brightness. While you’re at it, notice the sparkling background stars surrounding the moon — a stunning juxtaposition. Mamma mia!

I made a cosmic call to my favorite Italian, Auntie Rosie (rest in peace), and asked if she thinks the moon at total eclipse resembled one of her scrumptious pizza pies. She replied, “Oh, Marko, it certainly does! Mangi! Mangi!” Translated: “Eat up! Eat up!” Ah, that’s amore.

Interested in observing the eclipse with Jupiter Jill and me? Shoot me an email for the details.

Clear skies!


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