International Observe the Moon Night 2019
The International Observe the Moon Night will take place on October 5, 2019. It is a worldwide celebration of lunar science and exploration, celestial observation, our cultural and personal connections to the moon.
This is the week of the lunar month when our natural satellite is best positioned for after-dinner viewing and at looking its most picturesque. Keep your binoculars and telescopes handy and let’s observe the moon together!
Throughout the week, the moon will wax in phase and climb higher as it shifts east away from the sun. On Tuesday evening it will pass in front of the stars of Libra (the Scales). Once we get to mid-week the moon will be nice and high in a dark sky – perfect for telescope viewing. As the moon waxes fuller, the sun is rising over the moon’s eastern horizon. Locations along the terminator, which is the pole-to-pole line that separates the lit and dark hemispheres, are seeing the sun peek above the moon’s horizon. The near-horizontal sunlight arriving there casts long black shadows to the west and illuminates any elevated mountain, crater, ridge, or bump. Every night, the terminator shifts west, casting new parts of the moon into breathtaking relief. So there’s something new to see every night.
On Saturday afternoon, the moon will complete one quarter of its orbit around Earth (counting from the last new moon) and will reach its first quarter phase. At first quarter, the moon always appears half-illuminated on its right-hand, eastern side.
Several times a year at the moon’s first quarter phase, a feature called the Lunar X becomes visible in strong binoculars and small telescopes. For a few hours centered on approximately 11 pm EDT on Saturday, October 5, the illuminated rims of the craters Purbach, la Caille, and Blanchinus will combine to form a small, but very obvious X-shape. Using binoculars or a backyard telescope, look for the X along the terminator, and about one third of the way up from the southern pole of the moon (at lunar coordinates 2° East, 24° South).
Keep looking up and enjoy the moon with Star Walk 2!
