October 19, 2023

In the new book Mexico’s Valleys of Cuicatlán and Tehuacán, authors David Yetman and Alberto Búrquez provide an accessible and photographic view of the culture, history, and environment of an extraordinary region of southern Mexico. The Valleys of Cuicatlán and Tehuacán are lauded by botanists for their spectacular plant life—they contain the densest columnar cacti forests in the world. Recent archaeological excavations reveal them also to be a formative Mesoamerican site as well. So singular is this region that it is home to the Tehuacán-Cuicatlán Biosphere Reserve and a UNESCO World Heritage Site. The authors have been traveling to the area for two decades. Today, David Yetman answers a few questions about their newest collaboration:

What inspired you to collaborate on this work?

Alberto and I gained familiarity with Sonora via different routes, he as a Sonoran-born Cambridge-trained ecologist, I as a wandering desert rat trained in philosohy. We met at a field research school in Alamos, Sonora, sponsored by Tucson Audubon Society in, I believe, 1993 and immediately discovered our shared interests. We also realized rather quickly that our areas of interest complemented each other. Two years later we initiated a study of buffelgrass ecology in the small town of Tecoripa in eastern Sonora. During meeting key members of the community, we learned that representatives of the Mexican department of land reform were in the town discussing with townspeople the prospect of converting their cooperatively owned lands to private. We at once realized this was a historic moment in Sonora and spent the next year following the privatization procedures and interviewing the landowners involved. We published an article with our findings in 1997. In 2003 Alberto joined me in filming an episode of The Desert Speaks in the valleys called Cuicatlán in northern Oaxaca and Tehuacán in adjacent southern Puebla. We realized then that we had been pulled into a region with uncanny resemblance to the Sonoran Desert. We also realized that we enjoyed working together. Some twenty trips to that area later, we have published the book.

The plants in the region are so varied and so unusual that Mexico has designated it as a biosphere reserve, and UNESCO has followed, designating it a World Heritage Site. Why is the area so singular?

The valley’s peculiar location as connected desert valleys among several mountain ranges in the tropics has given rise to a bewildering variety of ecological zones or habitats, notably a desert environment where lusher vegetation would be expected. Those unusual conditions and a climate more or less stable for millions of years have combined to produce an astonishing array of desert plants, especially columnar cacti, many of which occur nowhere else. The high degree of endemism within the valleys means that it is the place to study these species and the evolutionary processes that promotes widespread speciation. At the same time, the region has seen the evolution of peoples of many different ethnicities. We long ago that discovered that they have stories to relate that complement the high diversity of the valleys.

The Valleys of Cuicatlán and Tehuacán also have a long human history. What are a few of the ways that visitors to the area today can see the continuity of human experience?

The archaeological sites within the valleys have not received the attention they merit, so visitors often must discover their location and history on their own. Alberto and I have presented four of these and their developmental history in a way that will assist visitors in locating and visiting these sites. One such site is Purrón Dam, which was the largest dam in the Americas two thousand years ago, but today not even located on maps. Another is the astonishing site of Cerro Quiotepec, located in an extraordinarily scenic hilltop far above where the two valleys converge and form a profound canyon. It is a highly developed site that was occupied for six hundred years before the Zapotec builders abandoned it in about 300 CE. At the same time the valleys’ varied resources have brought together at least eight different indigenous groups. They have established the human history of the valleys, with connections throughout Mesoamerica. Many towns in the valleys retain their indigenous identity.

What is your next project?

We have repeatedly discussed the importance of returning to Tecoripa after nearly thirty years to see what changes have occurred in the town’s social and economic structure because of the move from cooperatively owned to privately-owned land. We also have many places of ecological and social significance that we would like to visit, study, and describe. We have separate careers, but we remain close friends with a tacit agreement that soon we must find another area to visit, study, discuss, and describe. Sonora has a wealth of ecological and cultural surprises, all within a day’s drive of Tucson, less yet from Hermosillo, where Alberto lives. It is only a matter of time.

***
David Yetman is distinguished outreach faculty and a research social scientist at the Southwest Center of the University of Arizona, where he has worked since 1992. His research specialties include the peoples and ecology of northwest Mexico and the southwestern United States. Yetman has a PhD in philosophy and is author of numerous books and articles, including Sonora: An Intimate Geography, Natural Landmarks of Arizona, and The Saguaro Cactus: A Natural History. Yetman is the former host of the PBS series The Desert Speaks and current host and co-producer of the PBS travel/adventure series, In the Americas with David Yetman.

Alberto Búrquez works as a researcher at the Instituto de Ecología, Department of Ecology of Biodiversity, Universidad Nacional Autónoma de México. He is a co-author (with David Yetman) of The Saguaro Cactus.

February 7, 2023

In his new book The Sky at Night avid stargazer and astronomy columnist Tim Hunter covers all the basics—from the Moon, planets, and stars to the history and origins of constellations and selected famous astronomers and events. The book emphasizes naked-eye viewing with an occasional reference to using a pair of binoculars or a small telescope. Hunter encourages beginners to explore the skies while giving them a solid understanding of what they see. Building on his writings for the long-running Sky Spy column, Hunter defines and outlines astronomical terms and how they relate to locating objects in the sky. He weaves in his personal experiences of what he learned about astronomy as a columnist for more than a decade, detailing his mistakes and triumphs to help other would-be astronomers excel in this heavenly hobby. Today, he answers our questions.

What inspired you to write this book?

I am an avid amateur astronomer whose hobby has run amok.  I have always wanted to do an astronomy book but never had good idea or subject matter for such a book until I started writing the weekly “Sky Spy” column for the Arizona Daily Star.  I have written three academic radiology books and was familiar with putting together a book.  After writing Sky Spy columns for ten years, I realized the material in the columns would be ideal for a book on easy observing of the night sky.

You’ve been a columnist about astronomy for more than a decade.  What were the challenges in turning your column into a book?

When I began thinking about turning my columns into a book, I had more than 750 weekly columns that had been published.  There are many books where authors have combined their weekly or monthly columns into a book.  A lot of these are simply thrown together and renamed as a book without any major editing or condensation of the material.  My columns ranged from 250 to 300 words, frequently covering the same topic from year to year like the equinoxes or the solstices.  The columns were often Tucson or Arizona centric and very often date specific describing an astronomical event.

If the book were to have any worth, it could not just be columns thrown together and called a book.  There had to be a consistent whole and most Tucson and Arizona centric material had to be removed as well as most of the date specific material.    

Having to explain a concept to someone else means you must understand it as well.  I have often been chagrined to discover how little I knew about an astronomical topic when I first sat down to write a column about it.  When I finally got done with the column, the column might not be any good, but I sure learned a lot.

I picked important points from the columns and collated them, I hope, into an intelligible whole to be enjoyed by the reader.  I describe what I learned about astronomy and about being a columnist over the years.  I tell about my mistakes and occasional triumphs, advising other would-be astronomy columnists what to emphasize and what to avoid.  This book really is “the adventures of a sometimes astronomy columnist.”

Much of the best material for the Sky Spy columns has come from its readers through questions or complaints.  Constant reader feedback is essential for keeping a column fresh and relevant. 

Traditional newspaper columns are fading from public view due to the challenges facing print media in today’s digital world.  Even so, a blog or digital column needs as much input as possible from interested persons, readers and editors.  The sky is a wonderful draw.  It interests everyone in some fashion.  Put a telescope on a busy corner in the heart of a metropolis.  You will draw a crowd no matter the light pollution or surrounding urban chaos.  It is hard to beat the glory of Saturn’s rings or the craters on the Moon in a small telescope.  The summer Milky Way overhead on a clear night at a dark sky site rivals any digital trick available to the modern movie industry.  A total eclipse of the Sun is such a stunning experience that it has no serious rival in nature. 

What first brought you to astronomy?

I have been an amateur astronomer since 1950 when Miss Wilmore my first-grade teacher showed me a book of the constellations.  I was fascinated by a drawing of Cygnus the Swan and wondered whether I could ever see that in the sky.  That book has been published in the 1920s and did not list Pluto.  When I grew up in the 1950s and 1960s, Pluto was a planet.  Today, Pluto is now longer a planet, but that is a story for another time.  It turns out the book I though was outdated when I was in first grade is now back in style.

You advocate naked-eye viewing, and your book discusses objects easily viewed this way.  Why do you like this approach?

The sky is wonderful.  It is to be enjoyed day and night with easy viewing of the night sky the focus of the book.  All one has to do is step outside and look up.  I assume the reader is literate and interested in the sky but not particularly knowledgeable.  It assumes one is not familiar with most of the constellations, but it is hoped the descriptions provided and the directions given are good enough to find one’s way around the sky.  

There are many things you can easily see from your backyard even if you live in the city: the Moon, the planets, bright stars, bright satellites, the Earth’s shadow, conjunctions of the planets and Moon, eclipses, and bright constellation.  At a darker suburban location, you can even see a few star clusters and at least one galaxy with your naked eye.  If you add a good pair of easily held binoculars, you extend your viewing many times further. 

I will have succeeded if you enjoy the sky as much as I do and make friends with the Moon, planets, and stars. 

What are you working on now?

I have an observatory in my front yard in Tucson, the 3towers Observatory, and an observatory out of town near Sonoita, Arizona, the Grasslands Observatory (see: http://www.grasslandsobservatory.com ).  The Grasslands Observatory sits on a high 5000-foot altitude grasslands between distant mountains in all directions.  It has three telescopes that can be controlled remotely from Tucson and are used for astrophotography projects.  An ongoing project is to image all the 370 Barnard Objects in color.  These are regions of dark nebulosity which were first described and photographed in black and white more than 100 years ago by the famous astronomer E. E. Barnard (1857-1923).

***

Tim B. Hunter, MD, MSc, is a professor emeritus in the Department of Medical Imaging at the University of Arizona College of Medicine and has been the author of the Sky Spy column in the Arizona Daily Star for more than fifteen years. He is a co-founder of the International Dark-Sky Association and has received multiple awards for his work addressing light pollution.