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Book Review - Mystery of the Ashen Light of Venus

Posted: 30 October 2021


Mystery of the Ashen Light of Venus
Dr. John C. Barentine
273 pages
$30 (paperback), $20 (ebook)
Published 2021

Dr. John Barentine sent me a copy of his new book, Mystery of the Ashen Light of Venus. Dr. Barentine has a Ph.D. in astronomy, was formerly the Director of Public Policy for the International Dark-Sky Association (IDA), and recently formed his own company, Dark Sky Consulting, LLC. I have reviewed his previous two books, The Lost Constellations and Uncharted Constellations.

The Mystery of the Ashen Light of Venus is, as the subtitle states, an investigation into a 400-year old phenomenon. Dr. Barentine digs deeply into the history and science of this mystery to determine whether the Ashen Light is a trick of the eye, the result of defective optics, or a real observation based on science.

Table of Contents:

Prologue: The Martians That Never Were
"I Could See the Dark Part of Venus…"
First Light: Early Accounts of the Ashen Light 1643–1800
Going Mainstream: A Scientific Approach c. 1800-1900
What Is the Light? Historical Explanations of the Ashen Light
Venus as a Knowable World: Chasing the Ashen Light into the Space Age 1900–1980
New Ideas for an Old Problem: Observations and Science 1980–2020
Seeing What We Want to See: The Psychology of the Ashen Light
Perception Revisited: The Psychophysics of the Ashen Light
Epilogue: Evanescence and Evasion

The evening after receiving the book, I just had to take a photo of the cover with Venus in the background (along with my observatory).

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The book begins with the story of the so-called Martian "Canals", which were believed to be not only real objects on the Martian surface, but were built by Martians. These beliefs lasted for decades beginning in the late 1870s and continued well into the 1900s based on visual observations by experienced observers using excellent telescopes (for the time). I "saw" the "canals" myself, even though I knew they did not exist, using a friend's 6" Newtonian reflector telescope in the early 1960s when my vision was better than 20/20. It was a surprising "observation", and made it obvious that the human eye and brain can sometimes "see" things that do not exist.

Next, the book discusses the human cultural significance of the planet Venus. That is followed by documented Ashen Light observations over the centuries since the invention of the telescope. Possible explanations for these observations are discussed. The remainder of the book tries to answer the question of just what is Ashen Light using scientifically accurate studies, both of the eye and what might be occurring at Venus.

I have never observed or even tried to observe the Ashen Light, but I will now using what I learned from this book. Will I be successful? Who knows. I did "see" the non-existent canals on Mars in the early 1960s. As documented in my autobiography, I and some other observers saw the planet Mercury immediately after it ended transiting the Sun in May 1970. Maybe I will see (or not) the Ashen Light of Venus. I just hope I don't talk myself into thinking I observed the Ashen Light when nothing was there.


Does Mystery of the Ashen Light of Venus answer the question as to whether the Ashen Light is a trick of the eye and brain, the result of defective optics, or a real occurrence based on science? You get to decide using the evidence presented. Based on his extensive research of historical records going back several centuries, Dr. Barentine gives a very complete historical perspective on observations of Ashen Light. The science of possible explanations for Ashen Light is based on indepth research and interviews with experts. The book is an easy read, entertaining as well as informative. You will learn some history and some science, both in very readable and understandable ways.

Every astronomer should read Mystery of the Ashen Light of Venus and do their own observations of the planet. Maybe we can add more evidence to this 400-year old astronomical mystery.

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