Here are some of the presentations I have developed and given. The dates or range of dates indicate in what years I gave the talk. I have given two of them over the Internet via Webex. I have also supported local teachers with astronomy lessons in the classroom.

Click on the presentation name to see a brief summary below. Most of the presentations can be tailored for audiences ranging from families with young children to amateur astronomers.

Earlier presentations given with 35-mm slides are no longer available.

A brief biography is given at the end of this page.

Luna, Earth’s Moon (2019)

Lunar phases, super moons, and lunar features start the presentation. The middle gives scenes from the first and last Apollo landings on the Moon. The ending gives some of the findings from the samples brought back from the Moon that are pertinent to the Moon’s origin, and a brief summary of the Giant Impact hypothesis of the origin of the Moon.

This presentation was created to help celebrate the 50th anniversary of the landing of Apollo 11 on the Moon. In 2019, it was given to campers at Maine’s Lake St George State Park and to summer students at Thorndike Elementary School.

Apollo 11 astronaut Buzz Aldrin standing on the Moon's surface'

Apollo 11 photo from NASA

Out of this World Astronomy: The Orbiting Astronomical Observatory-2 (2019)

Artwork from NASA/GSFC

Artist's concept of the OAO-2 in orbit above the Earth
Orbiting Astronomical Observatory-2 was the first satellite to deliver astronomical data about stars, planets, nebulae, and galaxies to astronomers on Earth. It functioned from 1968 until 1973, and was an essential step in the progress to the Hubble Space Telescope. This is the story of that mission, its operations, and its discoveries. I helped to operate OAO-2 and prepared this talk in honor of the 50th anniversary of its launch into orbit.

The presentation was given at the Howard Astronomical League on March 21, 2019, and at the Space Telescope Science Institute on May 21, 2019. Click here to see a video of the version at the STScI.

Fifth grade students in Baltimore with the model comets they made in class

Supporting Teachers Under Project ASTRO

I have supported fifth grade teachers in presenting astronomy to their students through Towson University's Project ASTRO program, which is affiliated with the national Project ASTRO from the Astronomical Society of the Pacific. My contribution has consisted of presentations and hands-on activities, such as exploring the spectra of lights in the classroom, building a star finder, and building model comets using dry ice and other common materials. I participated in the 2014/2015, 2015/2016 and 2016/2017 school years.

The presentations I used for the fifth graders are:

  • Constellations
  • Comets
  • Astronomers (and their diversity)
  • Our Moon
  • Spectra
  • The Birth of Planets

The Ends of the Earth (2015)

Artwork from NASA/JPL

Artist's concept of a 
    planet orbiting at the surface of a star
Fire or ice? With a bang or with a whimper? How will the third planet from the Sun end its days? No one knows for sure, but scientists have ideas on which possible endings are likely and which are improbable. I discuss some of these possibilities. I present human-made hazards, such as global warming and nuclear war, as dangerous to humanity, but not to the Earth itself. Natural hazards range from the extremely unlikely collision with another world to the almost certain searing or engulfment by the dying sun in 5 billion years.

The idea for this topic came from a lecture by Neil deGrasse Tyson. The presentation was given at Coffman House in Falcon Heights, MN, and at Iron County Historical Museum in Caspian, MI, both in 2015.

Artist's concept of Kepler
       in space with a transiting planet in the background   
Image from

Got Planets?

Got Planets? tells the story of the more than 1,800 exoplanets - planets orbiting other stars - that have been discovered in the past two decades and the more than 4,000 candidates are waiting for confirmation. This presentation begins by describing some of the discoveries. The middle tells about three techniques that have produced evidence for exoplanets. The end discusses the search for planets on which life may exist and the challenges to be faced in finding life in the universe.

I first developed this presentation for families waiting to look through the telescopes at Idaho's Bruneau Dunes State Park during the summer of 2013. An updated version was used at the Iron County Historical Museum in Caspian, MI, in 2014.

Invisible Universe (2012)

Living on the Earth, nearly everything we know about the universe we have learned by seeing light from the celestial objects, whether that light is visible light, radio waves or X-Rays. Yet astronomers now think that the the universe filled with invisible stuff, stuff like black holes, dark matter and dark energy. In fact, they think that that the bulk of the universe is invisible. If we can't see these things, how can we ever know that they are there? And if the universe is filled with invisible things, what can we deduce about the nature of these things? This presentation describes some of the observations and measurements that that force astronomers to accept the invisible side of the universe.

Originally prepared for use during the summer of 2012 at Iron County Historical Museum in Caspian, MI, it was also given to families waiting to look through the telescopes at Idaho's Bruneau Dunes State Park during the summer of 2013.

Cartoon of dark matter and dark energy contending 
       over the expansion of the universe

Artwork from Space Telescope Science Institute

Variable Stars: Stepping Stones to Understanding the Universe (2011) R Coronae Borealis light curve from

The poet wrote, "Bright star, would that I were as stedfast as though art". On close inspection, however, stars are not steadfast. They become brighter and fainter with time, they are variable. To their first discoverers, variable stars were "Wondrous" and "Mischief-makers", unnatural intrusions upon the starry sky. Today, we know that nearly all stars are variable to some degree, yet they still elicit wonder in us. Some types of variable stars allow us to determine the size of our Galaxy and/or the age of the universe. Others are the sources of essential components for the making of our planet. They can even touch our lives - the study of variable stars allows ordinary citizens to enjoy the challenge and excitement of making significant contributions to science. This presentation introduces some of the people who have discovered and studied variable stars, explains what makes some stars vary, and shows how the study of variable stars has changed our concept of the universe.

You can watch the version presented at the Space Telescope Science Institute on April 5, 2011, here.

A version of this presentation was given to families waiting to look through the telescopes at Idaho's Bruneau Dunes State Park during the summer of 2013, and a different version via WebEx to members of the RASC at Saskatoon.

Hubble @ 20 (2010)

Image of Hubble in space   
In 1990 the Space Shuttle Discovery carried the Hubble Space Telescope into orbit. Since then the Hubble has generated remarkable images and astounding scientific discoveries. It has also experienced crises, both natural and man-made. This presentation gives an historical overview of the Hubble. It includes some of Hubble's "greatest hits" and their meanings. It also touches on mission's biggest crises, how the telescope works and who uses it, and how anyone can get Hubble data and even participate in research based on Hubble images.

In 2010, I gave this talk at: the Centro Cultural Salvadoreño Americano in El Salvador; Mott Community College and Longway Planetarium in Fint, MI; the Iron County Historical Museum in Caspian, MI; Coffman Condomium in Falcon Heights, MN; Brookwood Middle School in Genoa City, WI; and St. John United Church in Columbia, MD. In 2011, I gave it to members of the Marquette Astronomical Society at Northern Michigan University.

A version of this presentation was given to families waiting to look through the telescopes at Idaho's Bruneau Dunes State Park during the summer of 2013.

Sky Gazing (2010)

This presentation begins with constellations and how they can help you find your way in the sky. It continues with brief discussions of some of the great puzzles facing astronomy today, puzzles that today's young people may solve. It ends by describing the roles of some professional and amateur astronomers.

I first prepared this program to encourage scouts to undertake badge projects in astronomy and space exploration, and then adapted it for a general audience.

The constellation Orion

Saturn's moon Enceladus                 Wondrous Worlds (2008, 2017)

In recent decades astronomers have learned many surprising things about the nature of planets, moons and asteroids and about the forces that affect them. Much of what we have learned leads to further questions. Big questions remain unanswered. Is there life outside the Earth? Is there intelligent life elsewhere in the universe? Can we live on other planets? This presentation uses images from space missions and from telescopes on the Earth to report about some of the exciting findings in our solar system, especially on Mars and Titan, and about the search for planets of other suns.

In 2017, I prepared a new version of this, titled Strange and Wondrous Worlds. The new version dealt with evidence for water on Enceladus and Europa, high resolution observations of Pluto and Ceres, and concepts about how the Solar System was formed.

Behind the Scenes at HST (2006-2019)                         A view of the Flight Operations Room
when it was located at the Space Telescope Science Instiute

What do observations from the Hubble Space Telescope look like before they become press releases? How does the Hubble work? Who flies it? What are some of its surprising discoveries? What are the plans for telescopes after Hubble? These topics and more are discussed in this presentation.

Versions of this presentation have been given to families waiting to look through the telescopes at Idaho's Bruneau Dunes State Park during the summer of 2013, to members of the RASC at Saskatoon via WebEx in 2014, and to campers at Maine’s Lake St George State Park in 2019.


Three Eyes On The Cosmos: HST, Kepler and JWST (2006)

This presentation was given as the post-banquet talk at the fall meeting of the American Association of Variable Star Observers in 2006. It discusses the status of the instruments on the Hubble Space Telescope, and the plans for repairing and replacing them during Servicing Mission 4 (which occurred during May 2009). The presentation also tells about the astronomical goals of the Kepler and James Webb Space Telescope missions.


Originally from the Upper Peninsula of Michigan, I graduated with a Bachelor of Science degree from the California Institute of Technology in 1966, and went on to receive a Ph.D. in astronomy from the University of Wisconsin-Madison in 1971. My thesis, carried out under the guidance of Dr. John Mathis, involved building computer models of planetary nebulae to try to understand why some appeared to have dense condensations embedded in them.

My first job after getting my Ph.D. was at Goddard Space Flight Center where I helped operate the Orbiting Astronomical Observatory-2, the first successful astronomical satellite. The OAO-2 was designed to provide ultraviolet photometry and low-resolution spectroscopy of stars, planets, and other celestial objects. During that time I grew to love observing variable stars. With the OAO-2 we made the first ultraviolet observations of a supernova as well as many other variable stars. After the OAO-2 suffered a power supply failure in 1973, I returned to Madison to help reduce its observations.

In 1977 I joined Computer Sciences Corporation to operate the International Ultraviolet Explorer from Goddard Space Flight Center. The IUE was a fun observatory because we were always in real-time communication with the telescope. We were able to react immediately to new information either from the IUE itself or from other sources. This made it excellent for studying variable sources. During this time, I obtained new results on dwarf novae and other cataclysmic variables, on R Coronae Borealis stars, on eclipsing binaries, and even on pulsating white dwarf stars.

In 1983 I joined my colleagues at the Space Telescope Science Institute to prepare the ground system for operating the Hubble Space Telescope. At the Science Institute, I served as manager for the Observation Support System team and then for operation of the OSS-PODPS Unified System. Most recently I served as Branch Chief for Data Processing and Archive Services until I retired in summer 2010.

Because of my interest in variable stars I became active in the American Association of Variable Star Observers. I was a member of the Council of the AAVSO from 1990 until 1998, and served as president of the organization from 1995 to 1997.

I have been giving public talks about astronomy since the early 1990's. Most of the material is suitable for the general public, although I have done presentations for students in fifth grade and, on the other end of the scale, for amateur astronomers.

Responsible: Albert Holm
Updated: 18 March 2023