Featured Photograph
Crescent and Soap Bubble Nebulae
© 2026 Matt Anderson
This is an image of the Crescent Nebula and, to its lower left, the spherical Soap Bubble Nebula. The former (NGC 1688) is a beautiful emission nebula resulting from a massive Wolf-Rayet star shedding its outer layers. The latter is a planetary nebula – a shell cast off by a dying star. Both objects are found in the constellation Cygnus.
This image was created using about 25 hours of Ha and O-III data, as well as three hours of RGB data for the stars. The O-III signal, heavily concentrated in the outer shell of the Soap Bubble Nebula, allows it to be seen against the strong Ha background.
Matt Anderson
The featured photograph is any astronomical photograph provided by one of our members. If you are a member and have a photograph you would like to submit, please refer to the Featured Photo Guidelines for more information. The submission deadline is the 15th of each month.
Saturday, October 17, 2026 (Moved from October 24th)
Presenter: William Sheehan
Title: Roaming the Dark Skies of a World Lit Only by Fire: Astronomical Glimpses from the Upper Paleolithic
Description: This will be effectively the way that members of our species who painted the caves of the Upper Paleolithic, including the Pleiades on the ceiling in the Hall of the Aurochs at Lascaux, viewed the astronomical objects of their world. I hope to invoke a bit given my background in neuroscience the likelihood that they were wired rather differently from us, and had a very different experience of the world around them, which we could hardly imagine. I would like for this to be attended not only by CAS members but also warmly invite members of the Flagstaff Dark Skies Coalition to what I hope will be a pleasant evening of telling tales around the campfire.
Bio: William Sheehan is a retired psychiatrist, astronomy historian and author, and amateur astronomer. He has written 30 books including, most recently, "Solar Eclipses," "The Solar System" (with Cliff Cunningham), "Parallel Lives of Astronomers: Percival Lowell and Edward Emerson Barnard," "Space Age Generation" (with Klaus Brasch), "Discovering Mars" (with Jim Bell), "Discovering Pluto" (with Dale P. Cruikshank"), "Northern Arizona Space Training" (with Kevin Schindler), etc., etc. He is a long-time contributor to Sky and Telescope and the Biographical Encyclopedia of Astronomers, and has contributed a chapter to Astronomy and Philosophy: Conceptual and Methodological Foundations and Challenges (Cambridge U Press, 2026).
CAS Monthly Meetings and Astronomical Programs are held the
Saturday closest to the Full Moon at the Mars Hill Campus of
Lowell Observatory, Hendricks Center for Planetary Studies
Auditorium (6:45 pm - 8:00 pm), unless otherwise noted followed
by refreshments, and informal discussion. Meetings are open and free
to the public.
