May 28, 2017

Review: The Journey to Palomar.

Out from PBS!
Out from PBS!

Any groundbreaking construction project has its own unique tale, and the ascent of some of the great telescopes of the world is no exception. This week, we look at PBS’s landmark documentary, The Journey to Palomar, the story of a man and the rise of American astronomy to pre-eminence on the world scene.

 Hale hard at work circa 1905. (Public Domain Image).

Hale in his natural habitat…hard at work circa 1905. (Public Domain Image). 

 George Ellery Hale was a genius who, like many before or since, was nearly driven to madness for his visionary efforts. Palomar traces the pattern he established for undertaking huge observatory construction projects, starting with his first goal that established a precedent for all others; the construction of Yerkes Observatory. The crown gem of the facility was the 40” inch Yerkes refractor, still the largest of its kind used for scientific research to this day. Yes, we know the French built a 49” refractor for the Great Paris Exhibition in 1900, but that beast proved unusable! The Yerkes refractor also marked an end for an era of 19th century astronomy; a larger refractor will probably never be built. An almost as revolutionary breakthrough was the moveable floor designed to bring the observer up to the eyepiece; this floor collapsed once shortly after construction. The film also quotes Simon Newcomb’s now famous remark that “We are probably nearing the limit of our knowledge in terms of astronomy” when in fact, the voyage had yet to really have begun!

Yerkes 40-inch refractor.

The Yerkes 40″…Notice a famous somebody? (Credit: Observatory/University of Chicago).

A perfectionist, Hale was on a lifelong quest to build larger and larger instruments. This pursuit drove him westward to found the Mount Wilson observatory in California. With funding from the Carnegie Institution, ground was broken in 1904 and first light was achieved in 1908. The observatories built by Hale displayed a fundamental shift in thinking; it was slowly becoming realized that not only the instrument, but the site selected was crucial to astronomical success. Hale’s observatories were not just lone instruments, but research complexes dedicated to science and astronomy.

 Top scope for its time: the 100" Hooker reflector! (Credit: Mount Wilson Observatory).

The venerable 100″ Hooker telescope. (Credit: The Mount Wilson Observatory).

 At the time, the 60”inch was the largest operational telescope in the world, the 72” inch Leviathan of Parsontown having fallen into disrepair. Eventually, Hale would surpass even this with 100” inch Hooker telescope, the largest and most ambitious project of its day. Completed in 1917, this scope pushed Hale to his physical and mental limits; he suffered mental fatigue, and sought relief from the immense personal pressures by sojourning in Europe. He even committed himself to several psychiatric regimens after confiding that he was suffering from hallucinations… alas, it seems that it’s never truly a great work for science and man until someone loses their mind! The Journey to Palomar explores the trials that Hale suffered through on his quest in poignant detail. The Hooker telescope itself made possible one of the great discoveries of the 20th century; Edwin Hubble’s realization that faint “nebulae” were actually galaxies beyond our own! So much for that “we know everything” guy…

But Hale wouldn’t live to see his final act play out; the construction of the 200” inch reflector atop Mount Palomar. Projects of this scale simply had no template to build off of; whole new techniques had to be devised for the figuring and polishing of the massive mirror. Construction began in 1936, and the promise of the Palomar observatory was perhaps the one great shinning light during the Great Depression. The initial glass pourings were true media events; the process itself was slow and tedious and had to be repeated several times. Corning Glass Works initially experimented with fused quartz in the initial castings but eventually settled on a new material known as Pyrex for its low thermal expansion qualities.   Hale passed on in 1938; work on the telescope was halted during World War II but the instrument that now bears his name saw first light in 1949. Footage of the final polishing process is just plain cool to watch; did you know that final polishing was done with bare fingers? Ultimately, the engineers had to pry the 200-inch away from the opticians loving hands and simply proclaim the mirror as “done”; polishing might have continued to this day! Journey to Palomar also traces the story with comments by noted scientists and authors such as astrophysicist Wendy Freedman. The Hale telescope was to a generation what Hubble and Keck are today; I vividly remember Palomar being the pinnacle of astronomy as a child of the 1970s. These days, apertures are measured in meters, and several of Hale’s masterpieces now have the modern trappings of CCD cameras and adaptive optics to remain competitive. But Hale’s visionary mastery of astronomy gave us a glimpse of what might be possible, in a field where everything may truly never be known. Do give Journey to Palomar a look for a fascinating glimpse in astronomical history. The title is available via Netflix, but the truly good news for those who read this far is its still currently up on Hulu for free viewing! Now what would Newcomb thought of that and the idea of Internet astronomy? 

The Mt. Wilson 60". (Credit: The Mount Wilson Observatory).
The Mt. Wilson 60″. (Credit: The Mount Wilson Observatory).

05.06.10: An Exoplanet Family Portrait.


The worlds of HR 8799. (Credit: NASA/JPL/CalTech).

The worlds of HR 8799. (Credit: NASA/JPL/CalTech).


   Astronomers have recently accomplished another amazing first; the first images of an exoplanetary system taken with modest sized optics. But to perform this feat, several ground-breaking techniques had to first be pioneered. The target was HR 8799, a known exoplanetary system 120 light-years distant in the constellation Pegasus. The instrument was the Hale telescope just north of San Diego, and the team was out of NASA’s Jet Propulsion Laboratory in San Diego. Using a combination of coronagraph and masking the scope down to a diameter of 1.5 meters in diameter, the team was able to capture the above resulting image. The revolutionary “funnel coronagraph” was necessary to block the swamping light of the parent star; the masking was used to maximize the use of adaptive optics. The image was also taken in the infrared, an area of the spectrum in which the young hot planets generate the most energy. “The trick is to suppress the starlight without suppressing the planet light,” Stated JPL Astrophysicist Gene Serabyn. To give you a sense of scale, the three exoplanets pictured lay about 24 to 68 A.U. from their host sun; our own Jupiter orbits at a distance of about 5 A.U. Not only will the technique be capable of being scaled up for the observatory big guns, but it could also prove effective for space-based platforms, where a tension always exists between what astronomers would like to launch and payload limitations. Expect to see more exoplanet images via this method in the near future!