Historical Astronomer of the Month:

Giovanni Schiaparelli

Presenter:  Connor Justice

This month we are highlighting Giovanni Schiaparelli.

Main Presentation:  

Man and the Universe

Presenter:  Doug Smith

For our main topic, Doug Smith will be trying something new for this, with  a topic he has titled “Man and the Universe”.

6:30 pm – Main Presentation

TITLE:  Sun Daggers and Simple Noontime Sun Observations; From the Hohokam and Ptolemy to Kepler and Einstein

PRESENTATION: All cultures have specialists and laypeople observing the Sun, for purposes ranging from calendars (for planting and ritual days) and timekeeping, to astronomy research (e.g., sunspot counts, Earth’s orbit, and the gravitational bending of light).  For TAAA, Dr. Schaefer will share two sets of his research with naked-eye observations of the Sun from the Tucson area that are of interest to amateur astronomers, professional astronomers, and historians of astronomy. One set of research concerns the many sun daggers—dagger-shaped gaps in shadow created by sunlight steaming through crevices in rocks—etched onto rocks by the Hohokam Indians (c. 1000 AD) as markers for solstices and equinoxes for ritual purposes.  His research (with Jim Stamm) on sun daggers from spiral petroglyphs at Picture Rocks, Signal Hill, and Cerro Prieto prove the solstitial alignments were intentional.  

Another local observing program has been to accurately measure the Sun’s analemma; a diagram that shows the position of the Sun as viewed from a fixed position on Earth over the course of a year. With these observations for the Astronomical League Observing Award on the Analemma, he can define Earth’s orbit, and derive Tucson’s latitude, the obliquity of the ecliptic, the dates of solstice and equinox, the eccentricity of the Earth’s orbit, and the date of perihelion. This is a modern empirical test of the ancient Greek discoveries that led them to introduce epicycles. Dr. Schaefer’s modern data can also be used to test and prove the three Kepler Laws.  And all this, he says, is possible “by making quick naked-eye observations, with simple and cheap equipment, from my front yard.”

BIO:  Dr. Bradley Schaefer received his Ph.D in 1983 from Massachusetts Institute of Technology and is Professor Emeritus in the Department of Physics & Astronomy at Louisiana State University. His wide range of interests include many areas of astrophysics, as well as many aspects of astronomical events in history (e.g. the Crucifixion and the Star of Bethlehem) and in literature. For his work on the Supernova Cosmology Project which led to the discovery of dark energy and for which its leader, Saul Perlmutter won the 2011 Nobel Prize in Physics, Dr. Schaefer received a share of the 2007 Gruber Cosmology Prize, and the 2015 Breakthrough Prize in Fundamental Physics.

7:15 pm – Seasonal Star Information

Presented by Mary Turner.

Main Presentation:  

Biography of Edwin Hubble

Presenter:  Connor Justice

Our only presentation this month will be a biography of Edwin Hubble, name bearer of the Hubble space telescope.

TITLE:  Space Domain Awareness for Sustainable Orbital Space 

PRESENTATION:  The orbital space around the Earth is congested, contested and competitive. Over the last decade, the number of operational satellites has increased >250% and the number of orbital debris has doubled. With the impending launch of commercial mega constellations, the sustainable use of orbital space is questioned. As humans expand their footprint beyond near-Earth environment into cislunar space (between Earth and the moon), there is a critical need to detect, track, and characterize space objects not only for space traffic management but to avoid strategic surprises. Dr. Reddy’s talk will be a primer on space domain awareness, including a synopsis of the current situation, highlighting key challenges ahead and the application of planetary science techniques to resolve some of them.

BIO:  Dr. Vishnu Reddy is a planetary scientist and an infrared spectroscopist researching connections between asteroids and meteorites to understand Solar System formation and evolution. His research also focuses on space objects in cislunar space for the US Air Force. He received his doctorate from the University of North Dakota (UND) in Earth System Science and Policy (2009) and was a post-doctoral researcher at Observatório Nacional, Brazil (2010). While a Research Assistant Professor at UND (2010-2013) he worked with the Max-Planck Institute for Solar System Research in Germany on NASA’s Dawn mission to asteroid (4) Vesta. He subsequently worked at the Planetary Science Institute (2013-2016) before moving to the University of Arizona (2016-present) where he is an Associate Professor in the Lunar and Planetary Lab. He served as the investigation team lead (2015-2020) on NASA’s Near-Earth Object Surveyor Mission to discover 90% of near-Earth objects (NEOs) larger than 140 meters. Currently, as Director of UA’s Biosphere 2 Space Domain Awareness Observatory Complex, he oversees all ground-based optical/infrared and passive radio frequency space surveillance assets. Asteroid 1981 EQ28 has been named (8068) vishnureddy by the International Astronomical Union in recognition of his contribution to planetary science.

Main Presentation:  

History of Large Telescopes

Presenter:  Stephen Ferris

This month our main topic will be on the history of large telescopes presented by Stephen Ferris.

TAAA’s next General Member Meeting will be held on Friday, June 3, 2022 at 6:30 P.M. This will be a hybrid meeting (both in person and online). TAAA members will receive a Zoom link should they wish to attend remotely. The public may attend in person or online through our Facebook page https://www.facebook.com/TucsonAstronomy. (This being our first hybrid meeting, please be patient as we work out any technical kinks!)

6:30 pm – Main Presentation

TITLE:  Imaging Giant Planets Forming Around Young Stars 

PRESENTATION:  Giant planets form within the first few million years of a system’s lifetime. After formation, these massive planets interact with their birth disks and gravitationally sculpt the environment of subsequent planet formation. Recent technical advances have enabled observations of the first few giant planets while they’re still forming and interacting with their parent disks. These planets induce large-scale structural changes in the disks alongside their on-going formation. And Dr. Kevin Wagner’s talk will highlight the first images of gas giant forming planetary systems. It will cover how these images are produced, what goes into their interpretation, and what they teach us about the formation of systems with giant planets (including our own solar system). 

BIO:  Dr. Kevin Wagner is a NASA Sagan Postdoctoral Fellow at the University of Arizona’s Steward Observatory. After growing up in Kentucky and Ohio, Dr. Wagner studied at the University of Cincinnati before receiving his Ph.D. at the University of Arizona. His research focuses on directly detecting and studying planets around nearby stars, such as Alpha Centauri, with a specific focus on finding and characterizing potentially life-supporting planets and understanding how planetary systems form and evolve.