The October Dance of the Earth, Moon, and Sun Over New Mexico
On the morning of Saturday, October 14, 2023, New Mexico skywatchers will have a chance to experience a rare event – an annular solar eclipse. An annular eclipse occurs when the Moon passes directly in front of the Sun but does not block out the entire Sun’s disk. Instead, a ring of the Sun is visible for a few minutes – the so-called “Ring of Fire.” It is important to know that this Ring of Fire is bright enough to damage your eyes without proper protection. In this article, we will explain what causes a solar eclipse, why there are different kinds of solar eclipses, where in New Mexico you will be able to see the Ring of Fire, and how to see it safely. We will also show where you can get a stellar view of the eclipse from public lands in the western US, courtesy of the Public Lands Interpretive Association.
What causes a solar eclipse?
A solar eclipse happens when the Moon passes in front of the Sun as seen from Earth. This can only happen when the Moon is in the New Moon phase because that is the point in the Moon’s orbit when the Moon is seen in the same direction as the Sun. If the tilt of the Moon’s orbit was the same as Earth’s orbit around the Sun, there would be a solar eclipse every New Moon. However, the Moon’s orbit is tilted compared to Earth’s orbit and so the Moon, Earth, and Sun line up close enough for an eclipse only twice a year. Furthermore, the Moon’s shadow is small at the surface of the Earth so only limited areas on the Earth can see a given solar eclipse.
The figure below shows the Earth and Moon to scale compared to the distance between them. The Moon is on average 239,000 miles from Earth, which is about 30 Earth diameters away. Although in this scale diagram, the Earth and especially the Moon are tiny, this shows why the shadow of the Moon is small by the time it reaches Earth. With the Moon only about one-fourth the size of Earth, the Moon’s shadow traces a narrow path on Earth during a solar eclipse. If you were to print out this figure so that the Earth-Moon distance was 10 inches, to the same scale the Sun would be a disk 3 feet in diameter and 324 feet to the right of the Earth. This gives some idea of just how precisely the Earth, Moon, and Sun need to line up for an eclipse to happen.
You can see the Moon’s shadow in a remarkable photo that was captured by a spacecraft orbiting the Moon during the last solar eclipse in April 2023, which was visible in Australia. You can see the entire shadow of the Moon as a fuzzy dark spot, with the exact center of the spot denoting the point on Earth where a total solar eclipse was visible.
Why are there different kinds of solar eclipse?
There are in general three types of solar eclipse: partial, annular, and total. If you are not at the center of the Moon’s shadow, you would see the Moon partially covering the Sun — like something is taking a round bite out of the sun. This is a partial eclipse. If you are standing at a place that will be in the center of the Moon’s shadow, for a brief time you will see either one of two types of solar eclipse — an annular eclipse or a total eclipse. So why are there two different types of eclipse when the Moon is directly in front of the Sun?
What is the difference between an annular and total solar eclipse?
If the Moon orbited the Earth in a perfect circle, every time the Moon was directly in front of the Sun, we would see the same thing. However, the Moon orbits the Earth in a shape called an ellipse, which is like an oval. That means the Moon is closer or further from the Earth at different times every month. Like any other object, when the Moon is closer it looks bigger than when it is further away. The diagram below shows to scale a comparison of how big the Moon looks from Earth at its closest and farthest points. Some news reports refer to the situation when the Moon is at its closest approach – and biggest – during a full moon as a “Supermoon.”
By a lucky coincidence for solar eclipse watchers, the Sun looks almost the same size as the Moon as seen from Earth. In reality, the Sun is about 400 times larger than the Moon, but it is also 400 times farther away from Earth than the Moon, so it looks to be about the same size in the sky. However, because the Moon can appear to be larger or smaller during an eclipse, depending on how far from Earth it is at that time, the Moon might appear either slightly smaller or slightly larger than the Sun as shown in the figure. If the Moon looks smaller than the Sun when it passes in front of the Sun, a ring of the Sun’s bright surface, or photosphere, will still be visible around the rim of the Moon at maximum eclipse. This is an annular eclipse, and the ring of the Sun’s disk will still be visible as the so-called Ring of Fire.
However, if a solar eclipse occurs when the Moon is closer and therefore appears larger than the Sun, the Moon will cover the entire bright disk of the Sun. This is a total solar eclipse. During a total solar eclipse, a fainter part of the Sun’s outer atmosphere, called the corona, becomes visible once all the light from the photosphere is blocked by the Moon.
What kind of eclipse will be visible in New Mexico on October 14?
Some people in New Mexico will see an annular eclipse at the time of maximum eclipse. Others who are not in the path where the Moon passes directly in front of the Sun will see only a partial eclipse. The figure below shows the apparent position of Moon and Sun during the eclipse as seen on the center path and also to the west and east of the center path.
If the Moon were a little closer to Earth on October 14, viewers in the central path would see a total solar eclipse as shown on the far right in the diagram below. That won’t happen this time, but certain places in the US will enjoy the sight of a total solar eclipse on April 8, 2024 (more on that later).
Where in New Mexico can you see the Ring of Fire?
Below is a map of New Mexico showing the center path where the annular eclipse will be visible as a brief “Ring of Fire”. The center path is the darker diagonal stripe running from Farmington through Albuquerque and Santa Fe and on to Roswell and Hobbs. Areas to the southwest and northeast will see a partial eclipse with the Sun shown at selected locations at the time of maximum eclipse.
Note that the entire eclipse is a slow event as the Moon slides in front of the Sun. The entire time from when the Moon first moves in front of the edge of the Sun, through maximum eclipse, and then off the opposite edge, will last about 3 hours. For those in the path of the annular eclipse, the Ring of Fire itself will be visible for up to almost 5 minutes, depending how close to the centerline of the stripe you are. For detailed information on how the eclipse will look from any location in New Mexico, check out this website.
The Public Lands Interpretive Association has created a map of public land sites in the western United States within the path of the annular eclipse. They also provide links for information on the National Forests within and outside New Mexico in the path. Some public lands in the path are Salinas Pueblo Missions National Monument, Bandelier National Monument, El Malpais National Monument, and Aztec Ruins National Monument. Find more public lands in the annular eclipse path in New Mexico, Utah, California, and Oregon on the Public Lands Interpretive Association’s website.
Can I look at the Sun during the eclipse?
NO, not without proper eye protection! You cannot look directly at any part of the bright disk of the Sun at any time without causing damage to your eyes. There are several safe ways to view the eclipse, but you must prepare beforehand, either to purchase some inexpensive but safe eclipse glasses, do some research and plan a visit to a local group that is offering safe viewing options, or make your own safe viewing solar projector.
Safe eclipse glasses are the equivalent protection of welder’s glass but in a special lightweight vinyl film. Regular sunglasses, darkened glass, or other homemade objects will NOT protect your eyes. The Public Lands Interpretive Association is selling certified protective eye wear here.
Note that proper safe Sun viewers will block out any other type of light so don’t wear these while moving around!
Groups in your area may organize a public event on October 14 to provide a safe viewing experience. These may include local astronomy clubs, schools or universities, museums, or other science outreach professionals. These events may have solar viewing glasses for sale (although these often sell out fast so it may be better to bring your own in case). They may also have specially filtered telescopes designed specifically for safe solar viewing.
Note that it is dangerous to view the Sun at any time with a telescope or binoculars without proper filtering. However, these solar filters are not inexpensive and most telescopes are not sold with a proper solar filter, so the safe bet is to search out groups that have purchased proper equipment and know how to use it safely.
Other safe viewing methods:
It is safe to project the Sun onto a flat white surface to indirectly see the eclipse. Here is a video by NASA Goddard Space Flight Center on a way to make a simple pinhole projector to indirectly view the Sun: How to Make a Box Pinhole Projector
Remember, you are not looking right at the Sun with a pinhole projector. You actually face away from the Sun and let light from the pinhole shine an image on the paper at the end of the box. The image will be small, but you should be able to make out the shape of the Sun as it changes throughout the time of the eclipse. You can build one now and test it out well before October 14.
Another website with a diagram of a pinhole viewer is here.
What’s the big deal?
With a possibility of two solar eclipses per year, annular eclipses in New Mexico must be common, right?
As it turns out, no. Remember, the path in the center of the Moon’s shadow on Earth is very narrow compared to the size of the Earth. So, for any given solar eclipse, most people will not see anything, or at most a partial eclipse. Plus, the exact conditions for an annular eclipse are not common. The last annular eclipse visible in New Mexico was actually fairly recent, on May 20, 2012. In fact, Albuquerque happened to be in the center path of both the 2012 and the 2023 annular eclipses. However, the next annular eclipse visible in New Mexico will not occur until November 15, 2077.
When will the next total solar eclipse occur in New Mexico?
While it may seem like a long 54-year wait until the next annular eclipse, the next total solar eclipse visible in New Mexico won’t happen until almost a century later, on June 25, 2169. However, the central path of the upcoming April 8, 2024, total solar eclipse will pass relatively close by through Mexico and Texas, specifically through Fredericksburg and Dallas. A map of the path of the total eclipse can be viewed here.
How does a total eclipse look different from an annular eclipse?
As we have already seen, the Moon appears larger during a total solar eclipse compared to during an annular eclipse. With the entire disk of the Sun blocked by the Moon, the sky gets dark enough to see the extended corona or outer atmosphere of the Sun (and even some stars during the day). The figure below shows the difference, with the left photo of the 2012 New Mexico annular eclipse taken through certified solar eclipse glasses.
Anyone in the center of the path of the 2024 eclipse will see 4 minutes of totality, when it is actually safe to look at the corona without eye protection (but ONLY during the brief times of total eclipse!). The sight of the Sun’s corona is spectacular and a rare sight indeed. Photos below of two recent total eclipses, a 2017 total eclipse in the United States, and the April 2023 eclipse in Australia (the same eclipse as seen in the photo from the Moon above), give some idea of the sight but pale in comparison to the live event.
Unfortunately, most hotel rooms along the path of the 2024 eclipse are already reserved but if you have friends or relatives in the central path you might plan to “just happen to drop by” on April 8. If not, New Mexico will experience a partial eclipse at that time, which can be viewed with the same eye protection as needed for this year’s annular event.
If you know when to look and prepare to look safely, there are many ways to experience the dazzling view of the always dramatic alignment of Earth, Moon, and Sun.
Story and diagrams by Dr. Chas Miller, New Mexico State University Astronomy Department
This article was posted by Cheryl Fallstead