This Week's Sky at a Glance

Some daily events in the changing sky for October 10 – 18.

All week, Venus is getting higher and easier to spot after sunset. Look for Antares, much fainter, moving in toward Venus from the left. Binoculars will help.

Friday, October 10

The red long-period variable star W Lyrae should be about at its peak brightness (8th magnitude) this week. Follow its doings with binoculars or a small telescope and the star chart.

Saturday, October 11

For western-U.S. observers, Jupiter's moon Ganymede disappears into eclipse by Jupiter's shadow around 9:39 p.m. Pacific Daylight Time. A small telescope will show it gradually fading away a little east of the planet.

Sunday, October 12

The Dumbbell Nebula, M27, is the brightest planetary nebula in the sky as seen in most instruments. Binoculars usually show it fairly easily.

Monday, October 13

Shortly after dark at this time of year, Deneb crosses nearly straight overhead (for skywatchers at mid-northern latitudes). West of Deneb shines brighter Vega.

Tuesday, October 14

Full Hunter's Moon (exact at 4:02 p.m. EDT).

Wednesday, October 15

The large asteroid 2 Pallas, magnitude 7.3, is 17 arcminutes east of the 2.8-magnitude star Beta Leporis during the predawn hours Thursday morning. At high power, watch for its very gradual motion with respect to the background stars.

Thursday, October 16

Early Friday morning, telescope users in western North America can watch the waning gibbous Moon crossing the Pleiades. Stars will disappear on the Moon's bright limb and reappear from behind its narrow dark limb. Of the six brightest Pleiads, only Maia gets occulted for most viewers. Local predictions.

The bright eclipsing variable star Algol should be in one of its periodic dimmings, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 1:37 a.m. Friday morning EDT; 10:37 p.m. Thursday evening PDT. Algol takes several additional hours to fade and to rebrighten.

Mercury is brightening day by day. Look for it low in the dawn far below Saturn.

Friday, October 17

For the next two weeks, little Mercury has its best dawn apparition of 2008 for skywatchers at mid-northern latitudes. Look for it low above the horizon due east (far below Saturn) as dawn brightens.

Saturday, October 18

Right around nightfall at this time of year, you'll find Arcturus sparkling low in the west-northwest — at the same height above the horizon as Capella is sparkling low in the northeast. Arcturus is sinking lower, and Capella is rising higher. How accurately can you time when they're at exactly the same altitude? (The time will vary depending on where you are in your time zone.)

For more information :

http://www.skyandtelescope.com/letsgo/whatsuptonight/30776159.html