Watch the Moon take a bite from the Sun

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October hosts a double whammy of eclipses this year. On October 8, the Full Moon ventures deep into Earth’s shadow and takes on its own ruddy hue as it basks in the light from all our planet’s sunrises and sunsets. And to top things off, on the afternoon of the 23rd, the Moon passes between the Sun and Earth and will take a significant chunk out of our star. This partial solar eclipse favors North America, with better views coming the farther north and west you live.

Fifteen days after the Sun, Moon, and Earth align, they do so again — this time with the Moon in the middle. On October 23, our satellite casts its shadow onto most of North America and the eastern tip of Siberia. From Canada, Mexico, and the Lower 48, this partial solar eclipse occurs in the afternoon. Those in Alaska will see the earliest stages during late morning.

The entire eclipse plays out for those west of a line that runs along the border between Manitoba and Saskatchewan southward through the U.S. Great Plains to central Texas. (All of Mexico except for the Yucatán Peninsula also will enjoy the whole event.)

lthough the eclipsed Sun hangs low in the sky for many observers, don’t let this discourage you. Some of the best eclipse images include pretty foreground objects, and the Sun’s low altitude will help on that score. Scout out some potential sites for photography in the days before and hope for clear — or at least partly cloudy — skies on the 23rd.

While western observers will enjoy more of the eclipse with the Sun higher in the sky, northern viewers will see the Moon take a bigger bite out of our star. People in Mexico will see Luna cover anywhere from a tiny sliver of the Sun up to about 40 percent of its diameter. The Moon blocks about 30 percent of the Sun along the Gulf Coast and more than twice that much in the favored regions of the northern United States and Canada. Greatest eclipse occurs in northern Canada in Nunavut Territory near Prince of Wales Island. From there, the Moon hides 81 percent of the Sun’s diameter from view.

Eclipse details for a representative sample of North American cities appear in the table at below. The times are all in local daylight time for the appropriate time zone, and a dash indicates that sunset occurs before the eclipse concludes. The Sun’s altitude and the percent of its diameter covered by the Moon are both for the moment of maximum eclipse.

City	Eclipse begins	Maximum Eclipse	Eclipse Ends	Sun’s Altitude	Coverage
Anchorage, Alaska	11:55 a.m.	1:11 p.m.	2:28 p.m.	17°	64%
Chicago, Illinois	4:36 p.m.	5:43 p.m.	—–	2°	55%
Dallas, Texas	4:48 p.m.	5:53 p.m.	—–	10°	41%
Denver, Colorado	3:18 p.m.	4:35 p.m.	5:44 p.m.	16°	56%
Los Angeles, California	2:08 p.m.	3:28 p.m.	4:40 p.m.	29°	45%
Mexico City	5:32 p.m.	6:09 p.m.	6:44 p.m.	13°	12%
San Francisco, California	1:52 p.m.	3:15 p.m.	4:32 p.m.	31°	50%
Seattle, Washington	1:35 p.m.	3:00 p.m.	4:20 p.m.	24°	64%
Toronto, Ontario	5:39 p.m.	6:20 p.m.	—–	0°	44%
Vancouver, British Columbia	1:32 p.m.	2:57 p.m.	4:16 p.m.	24°	66%
Winnipeg, Manitoba	4:08 p.m.	5:24 p.m.	—–	8°	69%

As mesmerizing as a partial solar eclipse can be, viewing it isn’t worth losing your eyesight over. The human eye acts like a lens, focusing incoming light onto the retina. If you’ve ever used a magnifying glass to focus sunlight onto a piece of paper, you’ve seen how easily our star’s radiation can burn. Unfortunately, the same thing happens when you look at the Sun, except it’s the retina’s delicate tissue that burns. Damage can occur in as little as 30 seconds even without optical aid and in a fraction of a second if you view through binoculars or a telescope. And because the retina has no pain receptors, there’s no warning that something is wrong.

Don’t get discouraged, however, as there are plenty of ways to observe the Sun safely without risking your eyesight. For a direct view, you’ll need a high-quality filter. A #12 or #14 welder’s glass works perfectly if you don’t mind the Sun having a greenish color. If you plan to watch the eclipse through binoculars or a telescope, you must use an approved solar filter that fits over the front end of your instrument.

You also can view the eclipse indirectly by projecting the Sun’s image. Make a simple pinhole camera out of two pieces of stiff white cardboard and a piece of aluminum foil. Cut a square hole in one piece of cardboard, and then tape the foil over the hole. Next, take a straight pin and poke a small hole in the center of the foil. To view the eclipse, let the Sun’s light pass through the pinhole and onto the second piece of cardboard, which serves as a screen. This technique works particularly well with a group of children because everyone stands with their backs to the Sun and avoids the temptation of staring at it.

You also can project the Sun’s image through a telescope. Use a 6-inch or smaller scope to avoid heat building up and a basic eyepiece with few optical elements. (The adhesives in some modern eyepieces can melt with extended solar viewing.) If all else fails — or you simply want company while you watch — consider visiting your local planetarium or science center. Most will be open during the eclipse, and the people will only be too happy to share the moment.