Earthshine

Using the Perkin Observatory at Dublin School, I captured the image below on a whim Saturday morning shortly before sunrise.

The skies were very good for deep-sky imaging Friday night / Saturday morning, and I programmed the equipment to collect data for different galaxy groups.  I began closing down at the beginning of astronomical twilight, but then I noticed the Moon just over the horizon.  Typically we never want to image an object so low in the sky, and using our deep-sky imaging equipment (designed for imaging faint objects) on the bright Moon seemed rather silly... But, in the spirit of experimentation, I slewed the telescope east until it was essentially parallel to the ground.  After testing different exposure times, I found this view interesting. 

We are looking at a small waning crescent phase of the Moon---this part is illuminated by direct sunlight.  But we also see the rest of the Moon---this part is illuminated by sunlight reflecting off of Earth.  The earthshine was barely visible to the naked eye, but, after overexposing the crescent, here's what we see!  The lunar maria, regions that are less reflective due to their different composition after volcanic eruptions, are clearly visible.