Guest Speakers



Verde Valley





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Background Pieces

Here is a little background on our speakers, their interests 
and the topics of their talks.




Bruce Koehn

April 14th, 2012

Professional - Amateur Collaboration


Bruce Koehn, Research Scientist

Bruce’s major research interests include near-Earth object discovery, real-time computer programming, and image processing. He works with Dr. Ted Bowell on the LONEOS project searching for near-Earth objects that may impact our planet.

Gerard van Belle

October 12, 2012



Gerard van Belle, Astronomer

Gerard’s research concentrates on the fundamental properties of stars — masses, linear radii, and temperatures. These parameters tell us about the internal structure and evolution of stars, which in turn is essential in understanding the plethora of new planets being discovered about nearby stars. He has also applied his interests in the highest-resolution, highest-precision, astronomical techniques to detect such planets and map the surfaces of stars.

Gerard has worked on every major optical interferometer on the planet, including the Infrared-Optical Telescope Array, the Palomar Testbed Interferometer, the CHARA Array, the Very Large Telescope Interferometer, and the Keck Interferometer. His pioneering stellar surface imaging work on PTI won him the first director’s research award at the Jet Propulsion Laboratory.


Brent Archinal

October 11, 2003

Mars Exploration 

Brent A. Archinal Professionally, Brent Archinal received his PhD from the Ohio State University Department of Geodetic Science and Surveying in 1987. For 13 years he was employed as an Astronomer at the U. S. Naval Observatory in Washington, D. C. His work there centered on performing research into methods for more accurately determining the Earth's orientation and improving the coordinate systems of the Earth and sky. In May of 2000 Brent began professional work on coordinate systems for the other bodies of the solar system with particular emphasis on improving the control network for the planet Mars and high-resolution mapping of proposed 2004 Mars landing sites.

Brent has also been an active amateur astronomer for many years. While attending Ohio State during the latter 1970's and early 1980's, his interest in observational and amateur astronomy grew. During this same time period he also became active in various astronomy clubs where he served in several official capacities, including as President, of the OSU Astronomy Club and the Columbus Astronomical Society. More recently he has been a member of the Richland (Ohio) Astronomical Society, the Northern Virginia Astronomy Club, and now the Coconino (Arizona) Astronomical Society.

He has long advocated that visual observers "push the envelope" of what is thought possible. After becoming one of the first to publicize the "Messier Marathon" during the early 1980¹s, in 2001 he become the first (and at this writing, only known) person to observe all 110 Messier objects in a single night using binoculars. He made perhaps the first documented naked eye observation of the M 81 galaxy in 1995, the farthest object visible to the unaided human eye. In 1987, along with Bob Bunge, he made possibly the first known visual observation of a gravitational lens, the double quasar in Ursa Major.

Brent has a long interest in correcting various problems in the catalogs available to amateur and professional astronomers. His recent book (co-authored with Steve Hynes) on star clusters and the included catalog of star clusters is a direct outgrowth of that interest. In recognition of this work, in 2000 the International Astronomical Union named the minor planet no. 11941 Archinal. Brent currently resides near Flagstaff, Arizona with his wife JoAnne.

Paul Comba

June 28, 2003


Paul Comba grew up in Italy. He was always interested in astronomy - his parents had an astronomer friend who encouraged his interest. When he was 14 he got his first telescope, a 4 inch refractor. He now  has an 18 inch reflector with a ST8-E CCD. 

Paul came to America in 1946 at the age of 20 on a mathematics  scholarship to Cal-Tech.  He received his PHD in mathematics there  in 1951.  He taught Mathematics at the University of Hawaii until 1960, when he joined IBM as a software developer.

His interest in asteroids was piqued when he took "The Pilcher Challenge" to observe a specified number of  asteroids visually.  He far exceeded the target - eventually observing 1280 visually!

He discovered his first asteroid in 1995, photographically.  It was mag 16 , much brighter than the 19th & 20th mag asteroids he now  routinely discovers.  All subsequent discoveries were with the CCD - his total discoveries  to date: 1145. He  usually observes 13 nights a month, with three hours each night spent in the observatory and three to four hours per night at the computer in his study. 

He is the author of the Asteroid Club Observing Guide published by the Astronomical League. A pdf version of this document is available at

Tyler E. Nordgren

June 20
& June 21


Dr. Tyler E. Nordgren is Assistant Professor of Physics at University of Redlands, CA, and on the staff at Lowell Observatory. 

He has been part of the team working with the Navy Prototype Optical Interferometer (NPOI) at Flagstaff. You can read an article written by Dr. Nordgren titled "Plumbing the Depths of Polaris" by clicking here. Another interesting article by him is titled "The Optical Interferometer: Completing the Work of Galileo"

Another instrument, the Multi-channel Fourier Transform Spectrometer (mFTS) developed by Dr. Nordgren and others at the USNO, Flagstaff, may enable the detection of Earth-sized planets in orbits around other stars. Here is a link to an article about this effort. 

You can also read about the C-N (Chengalur-Nordgren) Galaxy Pair Sample, which is an ongoing project to determine the dark matter content of individual galaxies by using observations of the relative motions of galaxies in pairs. Dr. Nordgren's graduate work was on galaxy pairs.

No doubt we will hear about these and other "Unusual Objects" and the methods of observing them.

 Here is a link to his web page, updated as of Sept. 3, 2002.

Tom Polakis

August 16, 2003


Tom Polakis is a Contributing Editor of Astronomy magazine. He is a mechanical engineer in the aircraft engine industry. In his 25 years of involvement in amateur astronomy, his primary interest is the visual observation of the aesthetic beauty of astronomical objects combined with an awareness of what one is seeing. His writing about this subject has culminated in the Celestial Portraits series of observing articles that have appeared regularly in Astronomy magazine since 1998.

Tom also has an interest in astro-photography, particularly that which can be accomplished using simple equipment. When he isn't observing, he can be found pretending to be younger than he really is by playing roller hockey and ultimate Frisbee.

This write-up was taken from Astronomy Magazine's Staff Biographies. Click here to get the complete picture.

Robert Schottland

July 19, 2003


Rob Schottland is on the Board of AVV as Member-at-Large. It's hard to say how he came by that title (clearly not as a result of his physique). Most would say a better title would be “Renaissance Dude”. What is obvious is that he is interested in a great many things - he runs his own software and consulting business, travels incessantly, loves music and astronomy and is active on the Boards of Chamber Music Sedona and the Astronomers of Verde Valley, is into computers and gadgets, owns three dogs (two bearded collies and a border collie) and is neck deep into herding trials. If he didn't have his wife, Betty, to help him, you'd wonder where he found the time to do half the things he undertakes. 

Rob lives in Sedona (intermittently, as his travels permit) with Betty, Watson, Scooter and Dixie. Besides deserving sainthood for putting up with all this, his wife Betty has claimed herding championships with Dixie, the border collie. But that, as they say, is another story.

Rob redeems his "at-large" status by periodically entertaining and informing his fellow club members with well-researched talks on diverse subjects. We all remember his discourse on the Herschels - William, Caroline and John. Now he proposes to attack the rich lode of lore surrounding Isaac Newton. This should be interesting.