Stunning Example of Earthshine

A stunning example of Earthshine at the ESO

ESO/Petr Horalek

Sometimes you see a photograph that’s just so wonderful you can’t wait to show it to other people.

That shot above is one of those photos.

It was taken by Petr Horalek, a European Southern Observatory Ambassador — the ambassadors are a group of excellent photographers who shoot pictures of the ESO observatories for public outreach.

The photo was taken on April 6, just minutes before sunrise. Smack dab in the center is Venus, twin of the Earth, covered in clouds so reflective they make the planet the third brightest natural object in our skies.

Below is the crescent Moon, less than a day before its new phase. The crescent is so thin it’s almost an afterthought. Amazingly, the rest of the Moon’s surface was unlit by the Sun. So why can we see it? Earthshine! Light from the Sun hits the Earth, reflects off of it, illuminating the Moon, which then reflects it back into space, and to Earth. Our planet is very bright in the lunar skies, 50 times brighter than a full Moon. That’s enough to softly bathe the surface of our satellite in light.

The Earthshine effect is most intense just before and after the new Moons of Spring, especially right at sunrise and sunset. Since the latest new Moon was May 6, you still have an opportunity to witness optimum Earthshine effects for another day, maybe two. However, the next Springtime new Moon is June 4, so be on the lookout June 3 though 5.

Note, too, the Moon in the image looks a little squished. That’s an effect of our atmosphere, which curves along with the Earth’s surface. Near the horizon, the light from the bottom of the Moon goes through a thicker layer of air than the top part of the Moon. The air acts like a lens, bending that light, making the Moon look flat.

Horalek timed this photo perfectly, getting the shot just as the Moon cleared the distant mountains. Had he waited much longer the Sun would have lit things up too much anyway. This was a time exposure, too: You can see the faint stars of Pisces surrounding the Moon and Venus.

And let’s not ignore the foreground! The silhouetted dome houses the 1.2 meter VLT Auxillary Telescope, part of the Very Large Telescope array. Two other astro-photographers are seen wrapping things up after a long night of photography in the incredibly rich and dark skies of this remote location in the high desert of Chile.

I dream of capturing a photograph like this some day. But I just dabble in this; Horalek is a professional. I might feel a pang of jealousy seeing shots like this, but it evaporates rapidly as I take in the sheer beauty. I’m glad there are so many people out there willing to collect the few photons the Universe graces us with, and share them with the world.

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