One of the easiest ways to watch an eclipse is to check out the shadow of a tree or shrub against a wall or a building face, or even the ground.
If a wall or a building or the ground isn’t handy, then a sheet of white paper held behind the tree will work quite well.
Scientists and philosophers alike were puzzled for thousands of years as to how these little images of the sun, duplicated in great numbers, could be cast between the shadows of leaves during solar eclipses. The phenomenon had no doubt been seen for tens of thousands of years by ancient peoples. It is reasonable to suspect that some ancients saw the images several times in their lifetimes, perhaps often enough to ponder it as phenomena of religious importance. Perhaps the most surprising thing about these little discs is that they can be seen on any sunny day as full circles and yet they pretty much go entirely unnoticed throughout our modern lives.
The individual images of the annular eclipse pictured left are the result of an appropriate density of leaves of a juniper tree to break up sunlight passing through the foliage into individual beams that subsequently travel on to impinge upon a surface, producing the camera obscura effect.
Light originating from a source, say the face of the sun but really any scene, having passed through a very small hole, in fact a pinhole which can be simulated by the spaces between leaves, maintains its travel in straight lines to project the scene as an inverted image of same. Aristotle wrote with great interest about the effect around 350 BC, whereas it had been observed in China some hundreds of years earlier. The great Persian scientist Alhazen used the effect to project solar eclipses onto paper for safe viewing around the year c. 1,000. Leonardo da Vinci was keenly interested in the camera obscura effect.
Planning for photography of the October 14, 2023 annular eclipse was hit or miss because of the potential of crowds that could show up. Albuquerque, New Mexico, is a big place, but still, the track of the eclipse was straight through the city and serendipitously timed with the annual October ballooning event there, the International Balloon Fiesta.
The eclipses of 2012 (annular) and 2017 (total) had led to massive traffic jams along Interstate 15 through Utah. Remembering that downside, we jokingly gave Albuquerque a similar potential and assigned it a value, C (for Crowd), to denote the whole uncertainty as to how well the fiesta and the eclipse would be attended. For total traffic hassle, a distinct possibilty as well, we made a sort of educated guess as to a value we called H (for Hassle, of course). Then, there was the probability we could get lost travelling to any eclipse observation spot we selected and commited to, or worst still we would not find parking once we arrived there, and gave this uncertainty a value of D (for Dumb decision).
Perhaps a formal photographic excursion was not going to be possible, but rather a simple observation of the eclipse through appropriate eyewear; and, well, that could have occurred anywhere within the city or for that matter anywhere in the expansive valley beyond, an area of some 200 square miles. Altogether, to find a good location where our cumbersome telescope and photo equipment could be set up without interfering with the fun of other eclipse viewers, we needed a fail-safe plan. No such plan ever exists when readying for an eclipse. There is always uncertainty in the weather, the wild card of eclipse viewing. For days, the predictions for Albuquerque were for over 50% cloud cover on the day of the eclipse. Such cloud cover is usually unlikely in the Albuquerque area in mid-October. Fortunately, the clouds were a no show.
Some of the best eclipse viewing spots were near the balloon fiesta park and the open space areas nearby, especially along the beautiful Rio Grande River and its associated hiking trails and parks. These potential locations had high C, H and D values, and so—for a guaranteed spacious, if not private, venue for photographing the eclipse—we opted for an off-road trip into open terrain several miles out of town near the remote solar arrays, even though it meant traveling a considerable distance to the north from the fiesta park area.
Our elevation of 6,300 feet certainly added to an atmospherically cleaner view of the passing moon. Our view back to Albuquerque some 1,300 feet lower in elevation revealed a dusty haze over the city, possibly the result of the traffic activity of that morning.
As the eclipse was beginning around 9:15 AM on October 14, 2023, the morning festivities at the ballooning fiesta were just winding down. A view to the fiesta park through a 45X birding scope revealed a lone balloon still hovering over the park some 18 miles distant. As we had done in 2017 for viewing the total eclipse in Idaho, we used Xavier Jubier’s path calculations and chose a set up location for a bull’s eye alignment with the 2023 Ring of Fire. We located near the northwest perimeter of a vast, largely undeveloped subdivision crisscrossed with hundreds of dirt roads in the extended area around Rio Rancho.
As to being exactly on the track, for that we used GPS navigation*, but the moon’s path is not known to exact certainty and won’t be until a GPS network is sent into orbit around it sometime in the future; in addition, the mountains of the moon are not taken into consideration in the calculation of its shadow.
(*Actually, the correct term these days is GNSS navigation, meaning the combined use of many satellite networks including GPS, the American system, and GLONASS, the Russian system, and several others now hardwired into most commercial receivers; in other words, GPS technically refers to only the American satellite system which of course is the original.)
As the moon’s shadow moved across the face of the earth on October 14, 2023, it’s speed across the Albuquerque valley floor averaged about 2,500 miles per hour, about twice the speed of an F-18 fighter jet. To viewers on the ground, the eclipse appeared to start in the upper limb of the sun and drop vertically to the lower limb, moving slighty off to the left as it did so. For a good simulation of the eclipse, as would have been seen in alt-azimuth telescopes from Albuquerque, check out the animation at Time and Date. One of the more dramatic views of the annular eclipse was sent in to the Planetary Society’s space image library and can be viewed here. We think one of the most comprehensive and clear images of the eclipse is our own, as pictured below, because it shows the development of the eclipse as seen from the horizon, relative to the ascension of the sun as it reached high noon around the end of the eclipse. Look closely for sunspots which can be seen in the images.
SLIDESHOW BELOW: SOME FAVORITES FROM THE ECLIPSE
Click on any image in the blog photos below, or on the small arrow ⇒ button lower right, for enhanced slides of the photos. Photos by Barbara Swanson. (Nikon Z8, Nikon 200-500 mm lens)
The sun is seen rising as the moon begins to cross it at its upper limb, descending slowly for over an hour to reach perfect annularity, then descending further and to the left, relative to the rising sun, as the eclipse ended.
25 miles to the southeast of our eclipse observing station, Sandia Peak at 10,679' overlooks a ski resort and the Sandia Aerial Tramway, the longest tram in the United States.
The blurriness of the sun's images is affected by the focal lenths of the little "cameras" projecting the images onto the paper.
The moment of exact annularity lasts only seconds. It is captured on the paper in a multitude of bright rings so fleeting they are soon gone like a puff of smoke.
Oddly, only a few birds were seen in the remote high desert north of Albuquerque during the morning hours, but as the eclipse drew on, the light dimmed and the air cooled, with more birds becoming temporarily active.
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