Basic astronomy and night sky information
The Castaway Cluster, catalogued as NGC 6520, is located just above the spout in the “Teapot” of Sagittarius. This is a rich region of the Milky Way containing many gas clouds and star clusters, including the Lagoon and Trifid Nebulae. NGC 6520, a tiny jewel of a cluster, is often forgotten amongst these more famous sites [Read more…] about The Castaway Cluster
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The full “Corn Moon” arrives today at 18:35 UTC. This Moon is also a “Super Moon”, appearing 7% larger than an average full Moon. Look for it rising over the eastern horizon after sunset. It makes for a great photo-op, or for a little end-of-summer contemplation as the air turns cooler and the nights grow longer.
The August Full Moon is also called the “Grain Moon”.
(Image credit: Julie Falk)
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Ocean tides are one of the few phenomena that bring the workings of the sky down to Earth. The gravitational pull of the Moon, and to a lesser degree the Sun, tug on the world’s oceans while the Earth rotates under them, causing the ocean to appear to rise and fall twice each day. Isaac Newton applied his theory of gravitation to explain the tides. He reasoned that the Moon pulls on the ocean on the Moon-facing side of Earth, pulls on the Earth itself to a lesser degree because it’s further away, and pulls on the ocean on the far side of the Earth least of all. The effect is to cause the oceans to bulge slightly on a line towards the Moon as the earth rotates. So we see two tides each day spaced by 12 hours plus a little bit more to account for the Moon’s revolution around the Sun. Other than sunlight itself, tides are one of the most familiar astronomical phenomena we see around us.
In this time-lapse video by photographer Alan Dyer, you see the tides in action on the east coast of Canada, including the Bay of Fundy, a place in New Brunswick that boasts the highest tides in the world. It ends with a view of the Moon and Sun setting over the Bay of Fundy.
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