Astronomy Picture Of the Day (APOD)M51: Cosmic Whirlpool
Follow the handle of the Big Dipper away from the dipper's bowl, until you get to the handle's last bright star. Then, just slide your telescope a little south and west and you might find this stunning pair of interacting galaxies, the 51st entry in Charles Messier's famous catalog.
Mercury and the Chromosphere
Enjoying Wednesday's transit of Mercury from Dallas, Texas, astronomer Phil Jones recorded this detailed image of the Sun. Along with a silhouette of the innermost planet, a network of cells and dark filaments can be seen against a bright solar disk with spicules and prominences along the Sun's edge.
Halo and Hexagons
As a bright November Moon lit up the night sky last week, Gil Esquerdo spotted this lovely Moon halo overhead at the Whipple Observatory on Mt. Hopkins, Arizona. In the foreground, the structure...
Simulated Transit of Mercury
Mercury, the solar system's innermost planet, will spend about five hours crossing in front of the Sun today - beginning at 1912 UT (2:12pm EST), November 8. Specially equipped telescopes are highly recommended...
Janus: Potato Shaped Moon of Saturn
Janus is one of the stranger moons of Saturn. First, Janus travels in an unusual orbit around Saturn where it periodically trades places with its sister moon Epimetheus, which typically orbits about 50 kilometers away. Janus, although slightly larger than Epimetheus, is potato-shaped and has a largest diameter of about 190 kilometers.
The Ghostly Tail of Comet SWAN
What causes the structure in Comet SWAN's tail? Comet SWAN, which unexpectedly flared up to naked-eye brightness last week, has been showing detail in its ion tail that might be described as ghostly.
A Galaxy Collision in NGC 6745
Galaxies don't normally look like this. NGC 6745 actually shows the results of two galaxies that have been colliding for only hundreds of millions of years. Just off the above photograph to the lower right is the smaller galaxy, moving away.
Just before the rising Sun fully illuminated the 2,635 meter summit of Cerro Paranal in northern Chile, Gordon Gillet captured this stunning moonset. In the telephoto picture, a nearly full October Moon is silhouetting the impressive array of telescopes at ESO's Paranal Observatory.
V838 Mon: Echoes from the Edge
Variable star V838 Monocerotis lies near the edge of our Milky Way Galaxy, about 20,000 light-years from the Sun. Still, ever since a sudden outburst was detected in January 2002, this enigmatic star has taken the center of an astronomical stage.
"Nebula at the right foot of Andromeda ... " begins the description for the 76th object in Charles Messier's 18th century Catalog of Nebulae and Star Clusters. In fact, M76 is one of the fainter objects on the Messier list and is also known by the popular name of the "Little Dumbbell Nebula".