Thursday, February 15, 2007

Winter Skies Are Tricky

Winter Skies Are Tricky
by Dave Adalian

Icy February nights aren’t well suited to stargazing, but this winter the Solar System is putting on an early evening show that will have planet hunters back safe and warm at a reasonable hour.

But, when those would-be planet seekers trudge home they may feel frustrated as the skies are presenting a trio of difficult challenges this month.

In early evening since the year began the most brilliant of the planets, Earth’s twin Venus, has shone like a searchlight in the western sky in the hours after sunset. While there’s nothing difficult about finding this fiery gem after dark, those who like a real challenge can search for cloud-covered Venus winking in the deep blue while the Sun is still up.

To find any planet when the Sun is still above the horizon, it’s important to know exactly where to look. The easiest way to know where Venus will be is locating it just after sunset the night before a daytime search.

If that’s too easy, the try looking for Venus about 10 degrees to the left of the Sun--that’s about two widths of a fist held at arm’s length--and about 25 degrees above it--about five fists’ worth. Stand in a shadow to cut down on glare, and do not look directly at the Sun for any reason.

Despite any frustration this may cause, do not attempt to aid a daytime search with binoculars or a telescope because even a brief accidental view of the Sun can cause permanent eye damage or even blindness.

The next challenge has to be completed before Mercury moves back into the Sun’s glare this weekend. The innermost planet has just passed greatest elongation, when it appears farthest from the Sun, and it is visible just above the horizon right after sunset. Because Mercury never rises far from the Sun, it can be difficult to find and many longtime amateur astronomers have never viewed it, making it a feather in the planet hunter’s cap.

The final February planetary challenge is on the other side of the sky, where Saturn is now rising as the Sun sets in the west. To find it among the stars of Leo, look a bright light that doesn’t shimmer like the rest of the stars. The full moon will remove any doubt of Saturn’s identity on March 1 when it rides beside it through the sky all night long.


This column appeared originally in the Visalia (Calif.) Times-Delta on Feb. 15, 2007.