It isn’t every day that the moon blots out the sun. But this year there will be two solar eclipses, one on the 13th of November in the South Pacific which very few people will see and an annular solar eclipse in less than 3 weeks which many people will get to witness from China and Japan to most of the United State. In fact, you will participate in a brotherhood of mankind becoming eyewitness to one of nature’s most spectacular treats.
On Sunday May 20th, an annular eclipse of the sun comes to California. The term “annular” does not mean it comes once a year, but rather that the moon will appear as an annulus, or disk, in front of the sun. I suppose the bad news is that this will not be the other kind of eclipse- total. The moon’s orbit around the earth is not circular. Instead, like virtually every orbit in the cosmos, it is elliptical having a high point (apogee) and low point (perigee). Unfortunately, the apogee this month is on May 19th, just one day before the event. That means the moon will be farther away than usual- 250,000 miles. Its mean distance is about 240,000 miles, so the additional 10,000 miles distant will make the moon appear a bit smaller. Now, as it turns out, earth is also farther away from the sun than usual- making it smaller too. But alas, the moon will be the smallest of the two. In the end, only 94% of the sun will be covered by the moon’s disk.
That 6% of visible sun will seem bright. And that will be along the central path of the eclipse. Here in Kern County, the event can be viewed either through welder’s glasses or by reverse projection. It is never advisable for anyone to look directly at the sun without some type of eye protection. An excellent method alluded to above is the reverse projection technique in which you take a pair of binoculars and project an image of the sun through the eyepiece onto a piece of white cardboard. You can also simply take construction paper a poke a small hole it in with a pencil. Then place that above another sheet of white cardboard. The projected image will be that of a partially eclipsed sun on the cardboard.
The path of annuality is fairly large, extending from the Redding area of the northern Sacramento Valley, then southeast through Reno, then to the north of Las Vegas, right across the Grand Canyon, then Albuquerque and finally ending at sunset over the Texas panhandle. In Bakersfield, the first part of this eclipse happens when the initial edge of the moon crosses in front of the sun’s disk. That will be Sunday May 20th at 5:23 PM. As the sun slowly drops lower in the sky more and more of the sun will be covered until at 6:37 PM a total of 87% of the sun’s surface will be darkened on its right side. By then the sun will be only about 13 degrees above the western horizon. That is the maximum eclipse for this event in Kern County. Then, as the sun slowly descends toward sunset at 7:58 PM the dark moon will gradually move up over the sun’s surface eventually exiting the upper right edge of the sun at 7:43 PM, only 15 minutes before sunset. For most of the country, from east of California all the way to Pennsylvania and Alabama, the sun will set partially eclipsed that day. It will be quite a sight for anyone with relatively clear skies.
And with the sun at a low angle in the west, if we have haze that day (always a good bet in Kern County), there may be some visual relief leading to a darkening sufficient to view the eclipse directly. I am NOT suggesting anyone do that, but if the sun becomes dim behind the haze, it might be safe enough to view the sun.
This eclipse is part of the SAROS cycle number 128. That is a strangely predictable cycle in which the earth, moon and sun revisit a nearly similar orientation of all celestial objects. This cycle is recurrent every 6,518 days, or every 18 years 11 days and 8 hours. The first solar eclipse of this cycle occurred on August 29, 984 AD. The last one will be seen (presumably) on November 1, 2282. The most recent eclipse of this cycle was seen in the eastern US on May 10, 1994. Anyone remember that one? If not, you won’t want to forget this one. So make plans today to be outside enjoying the sunshine (in more ways than one) on Sunday May 20th. You will kick yourself if you let this one pass by.