Date:  January 26, 2009

Title:  60th Anniversary of Hale Telescope “First Light”

Podcaster:  Scott Kardel

Organization:  Palomar Observatory/Caltech

Description:   We’ll take a trip to the prime focus observer’s cage at Palomar Observatory’s Hale Telescope on the 60th anniversary of the “first light” photographs taken there by astronomer Edwin Hubble on January 26, 1949.   Included in the podcast will be the sounds and vivid descriptions of the prime focus elevator, the slewing of the 530-ton telescope and the rotation of the 1000-ton dome.  We’ll also take a look at astronomy taking place at Palomar now and compare the experiences of the modern astronomer to those of Hubble’s era.

Bio:   Scott Kardel received his MS in Astronomy from the University of Arizona and his BS in Physical Science / Secondary Education from Northern Arizona University.  For the last two and a half decades he has been working to bring an understanding of science and the universe to a wide range of audiences.  In 2003 he became the Palomar Observatory’s first full-time person devoted to public outreach. There he works to bring Palomar’s rich history and story of exploration on the road and on the Net to a wide variety of groups throughout Southern California and beyond.

Today’s Sponsor:  This episode sponsored by Dr. Kevin Marvel, the Executive Officer of the American Astronomical Society in memory of Dr. Thomas Swihart who taught him how to really do astronomy. Kevin challenges all of Dr. Swihart’s former students to sponsor one episode of 365 Days of Astronomy in his memory. Flopdiddle bugs forever!

Transcript: 

Welcome to another edition of the 365 Days of Astronomy podcasts.  Today is January 26, 2009.

I am Scott Kardel of the Palomar Observatory. Today we are remembering an important anniversary at Palomar.

On January 26, 1949, sixty years ago today, the 200-inch Hale Telescope at the Palomar Observatory finally saw first light.  The effort to build the 200-inch telescope, then the world’s largest, began twenty one years earlier in 1928 when George Ellery Hale received a six million dollar grant for the project.  The telescope’s design, construction and final calibration phases spanned the Great Depression and World War II.  This story was recently chronicled in a PBS documentary film about the career of George Ellery Hale known as The Journey to Palomar. Prior to Palomar Hale was the driving force behind the 40-inch refractor at the Yerkes Observatory and the 60-inch and 100-inch reflectors on Mt. Wilson, each of which was a leap forward for astronomy.

It was with the 100-inch telescope on Mt. Wilson that astronomer Edwin Hubble made two important discoveries. First that what where then called “spiral nebulae” were actually distant and distinct objects separate from our own galaxy, the Milky Way.  The second discovery was that the universe itself is expanding – many galaxies are receding farther from our own. The discovery of the expansion of the universe was made in 1929 with just a handful of data points.  A bigger telescope was needed to measure distances farther into space.  These distance measurements would help to strengthen the idea of the expanding universe and to establish the ultimate fate of the universe.  Would it expand forever or collapse back upon itself?

Twenty years after Hubble’s discovery he was certainly hungry for more data.  He was ready to begin the next phase of his work at Palomar.  The 200-inch telescope became the first telescope large enough for an astronomer to actually ride inside it.  Back then all astronomical images were recorded on photographic plates,  basically a piece of glass coated with an emulsion of film.  The astronomer had to make sure that the telescope was pointed correctly and at its best focus.  By looking at a star through a guiding eyepiece they would also guide the telescope as it moved to counteract Earth’s rotation.  If it drifted off of center they would carefully guide it back.

On Palomar, inside the 200-inch telescope the astronomer would ride in what is known as the Prime Focus Cage, some eighty feet above the observing floor. To ascend the astronomer would carry his plates and other gear with him up the steps to the prime focus elevator.  And slowly ride to the top of the 530-ton telescope.

As you likely guessed, that was the sound of the prime focus elevator making the trip up, although it takes longer than what you just heard.

Once the observer was inside, the telescope operator, located at a console on the observing floor, would slew the telescope to the first target and observing would begin.

Hubble’s first night on Palomar was mostly a demonstration to produce some nice photos. His first target was an object he knew well, having studied it previously at the Yerkes and Mt. Wilson observatories.  Today that object, NGC 2261, is often referred to as Hubble’s Variable Nebula.  Other objects were photographed that night with the results published in the astronomical literature and in Collier’s magazine.   You can see that first light photo on the Palomar Observatory website. Just visit palomar “dash” observatory.org.  Click on “astronomical images”, then “nebulae” and then scroll down a bit.

Hubble’s studies of the expansion of the universe were cut short by a heart attack and his untimely death in 1953. His work was carried on by his longtime observing assistant Milton Humason, his protege Allan Sandage and others.

Over the decades many astronomers observed from prime focus.  On cold winter nights conditions could take their toll on those observing.  Many astronomers chose to wear electrically heated war surplus flight suits.  Those nights are now long past.  No one has exposed a photographic plate in the Hale Telescope since 1989.  The flight suits are in storage and on display for the observatory’s many visitors.

At night the prime focus cage is now occupied by an electronic camera and the trip to prime focus is  made mostly by Palomar’s electronic technicians.

The astronomers now observe from the comfort of an office chair as they sit a warm room in front of their computer monitors. Gone is the cold of the night.  Some say that the romance has gone with it, but astronomers are happier and more productive.  Today’s electronic cameras are more sensitive to light than film ever was and we have new technologies like adaptive optics that give ground based telescopes like the Hale sharper view of the universe than ever before.

Weather permitting, Palomar’s Hale Telescope is used nearly every night of the year. So what are  astronomers studying tonight, January 26, 2009?  Some of the most energetic explosions in the universe-gamma ray bursts.

365 Days of Astronomy
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