Just two weeks after a total lunar eclipse, some lucky observers in North America will get to see a partial solar eclipse on October 23, 2014. The eclipse is visible from most of North America and Mexico. No observers will see the Sun totally eclipsed, but from western North America, about 40% to 80% of the Sun will be covered by the Moon. This is a great “dry run” for the total solar eclipse of August 21, 2017.
The partial eclipse begins at 19:37 UT, peaks at 21:45 UT, and ends at 23:51 UT. In eastern North America, the eclipse will be in progress or just beginning at sunset. West of the prairie states and provinces, the full eclipse will be visible in the afternoon before the Sun goes down. It will not be visible in Europe, Africa, Australia, and New Zealand. The map below shows you the region where you can see the eclipse, and the degree of totality.
This map shows, for example, that in San Diego the eclipse peaks at 22:30 UT (3:30 pm PDT) and the Moon will cover about 43% of the Sun. In my old home of Victoria, British Columbia, at the southern tip of Vancouver Island, the Moon will cover about 65% of the Sun at about 22:00 UT (3:00 p.m. PDT).
During this entire event, the Sun will be far too bright to observe with your eyes, so don’t try! You will need a proper solar filter. A piece of #14 welder’s glass will work if you are just watching with your eyes. A white-light solar filter will do the job with a telescope. More about solar filters here…
If you don’t have a solar filter or a telescope, you can poke a pin hole in a piece of paper and let the Sun shine through the hole onto another piece of paper. This makes a small and faint image, but it works in a pinch. Again, don’t look directly at the Sun if you use this projection method.
With the Sun covered by 60% to 80% during this eclipse, you’d think the land and sky would become darker. But most people do not detect such darkening because the human eye adapts to the changing illumination. In my experience, you don’t really notice much darkening until the Sun gets 85% to 90% eclipsed. But you may notice the sky becomes a darker and purer blue.
If you see the eclipse through a properly filtered telescope, have a look at the sunspots. You may notice they appear greyish-black rather than pure black compared to the Moon. That’s because sunspots appear dark because they are cooler than the visible face of the Sun, about 4,000 K compared to the Sun’s average temperature of 5,700 K. Also look along the limb of the Moon for the slightly jagged outline of lunar mountain ranges silhouetted against the Sun.
If you find yourself in a location where the Sun sets during the eclipse, find a good location to try grab an image if the Sun is well attenuated by clouds or if you have a solar filter for your camera lens. It makes for a great photo-op… but make sure the Sun is not too bright when you try an image because it can damage the camera sensor.