America’s First “Trip” to the By Robert Anderson

Mount Wilson is most famous for the work of astronomers , , and Milton Humason that answered some of the fundamental questions in cosmology. Many other astronomers working here helped piece together the story of stellar evolution and how magnetism on one , our Sun, governs its behavior. But what about the Moon? As we close in on the 50th anniversary of the Apollo 11 moon landing on July 20th, what contributions did the Observatory make to understanding our nearest celestial companion?

Ever since Galileo first trained his on the Moon in 1609, humans have strived to get a better look at it. got better, and in 1840, John Draper launched astrophotography with the first successful daguerrotype of the Moon. Mount Wilson’s George The Moon, imaged last year by Thomas Spirock on Mount Willis elevated the art to a high level. (see the Wilson’s 6-inch Warner & Swasey refractor installed in 1914. article in our last issue). His giant reflectors Using the “lucky imaging” technique (which uses only the recorded the best photographs of the Moon in the first sharpest images recorded at moments of the best seeing), he imaged the Moon’s four quadrants and combined them. half of the 20th Century. To Page 4 With modern detectors and processing, Spirock reveals the extraordinary quality of the mountain’s antique optics.

Saturday Evening, July 13 In this issue . . . Moon Diver: Return to the Sea of Tranquility A talk at the Observatory by Dr. Laura Kerber, Trip to the Moon ……..…….1 The Periodic Table Turns 150….7 a planetary research scientist at NASA’s Jet News + Notes …………………2 Observatory Visiting + Map…..8 Propulsion Laboratory, followed by a chance to look Alliance of …3 through the 100-inch Telescope

Mount Wilson is Open to Visitors Weather and roads permitting, will be open every day. Come on up to the mountain to enjoy the beautiful weather and uplifting surroundings! The Cosmic Café is open Saturdays and Sundays, 10 a.m. to 5 p.m., offering a variety of fresh-made sandwiches and other treats. The Café also sells National Forest Adventure Passes and tickets for the weekend walking tours at 11:30 am and 1:00 pm. On other days the pass can be purchased at the gas station at the bottom of the Angeles Crest Hwy. Check our website at mtwilson.edu for upcoming events and telescope rentals. See you on the top!

ANNOUNCEMENTS A B O U T U S

The Mount Wilson Institute NEWS + NOTES operates Mount Wilson Observatory on behalf of the 2019 CONCERTS AND TALKS AT Carnegie Institution for Science. MOUNT WILSON OBSERVATORY Mount Wilson Institute is dedicated to preserving the We are well into our busy season on the Observatory for scientific research mountain, with many first time visitors and fostering public appreciation coming up to enjoy concerts in the 100- of the historic cultural heritage of inch Telescope dome and science lectures the Observatory. Reflections is in the auditorium followed by viewing published quarterly by the Mount Wilson Institute. through the 100-inch or 60-inch telescopes. The Saturday Evening Talk INFORMATION and Telescope Night on July 13 is For information about the Moon themed (like this issue) to Observatory, including status, commemorate the 50th anniversary of the activities, tours, and reserving 60- first lunar landing. Visit us at Astronaut Buzz Aldrin of Apollo 11 takes a look inch and 100-inch telescope time, mtwilson.edu for more information. at through the eyepiece of the 100-inch visit our website: Telescope. He visited Mount Wilson last July to LOOK THROUGH OUR use the giant telescope to view during its close approach. mtwilson.edu TELESCOPES

✰ The 60-inch & 100-inch telescopes REFLECTIONS STAFF provide incredible views of some of the most beautiful objects in the night Editor/Designer sky, and are the largest in the world Robert Anderson accessible to public viewing. For [email protected] information on how you can reserve Copy Editor Angie Cookson time, available dates, fees, and make reservations — visit mtwilson.edu Special thanks to Docent Jed and click on the “Observing” tab at the Lederman for his help on Mount top. Use the same telescope Edwin Wilson’s lunar history. Hubble and Buzz Aldrin used!

✰ Don’t Want to Miss For the use of historical anything? photographs of Mount Wilson, we Buzz Aldrin in the 100-inch Telescope dome (easily identified) with Tom Meneghini, the director of the thank the Observatories of the Subscribe to Mount Wilson Observatory. Perhaps Tom is asking Buzz if he can Carnegie Institution for Science, Observatory News for updates on visit again next year to celebrate the 50th anniversary the Huntington Library, and other concerts, lectures, public telescope of the first lunar landing—and Aldrin is thinking of a sources as noted. nights, and other events. Sign up at tactful way to say he’ll probably be busy. Reflections copyright © 2019, mtwilson.edu Mount Wilson Institute PAGE ONE BANNER Help Sustain the Observatory PHOTOGRAPH (Inset) Astronomer Edwin Hubble The Observatory receives no regular support from government or at the Newtonian focus of the institutions.We rely on donors, a few small grants, and the revenue from 100-inch telescope on Mount our telescope nights to fund our continued operation.You can help Wilson, circa 1923. ensure the continued operation of this world class, science heritage site with your tax-deductible gift. We welcome donations of any size!Visit mtwilson.edu for information on how to support the Observatory through donations, memberships, or volunteering. Thanks.

REFLECTIONS 2 JUNE 2019

maintain their facilities and to extend public A LETTER FROM outreach programs for education. Each Observatory SAM , CHAIRMAN OF represented is unique in its own history and level of public support. Some, like Griffith Observatory are THE BOARD OF TRUSTEES well funded by private and government support, but others are not. For instance, near Preliminary Meeting of the Alliance Chicago (also founded by my grandfather George of Historic Observatories Ellery Hale) has recently been shuttered by the University of Chicago, and is searching for a way to On June 15-16, Mount Wilson Observatory hosted reopen its doors. In many ways it is in the same the first meeting of the Alliance of Historic situation Mount Wilson Observatory was in back in Observatories, a new organization being formed to 1985 when the Carnegie Institute of Washington promote the longterm support of observatories that withdrew its support in order to devote its limited played key roles in advancing our understating of the financial resources to building the next generation of Cosmos. The idea is to form a loose alliance that will big telescopes in Chile. Because the public cares explore ways in which we can support each other about history, science, and education we are thriving through shared promotion, lobbying, and other and so will Yerkes. means to ensure that the remarkable legacy of these observatories is preserved for future generations, to We had a productive meeting to explore ways

inspire and educate the next generation of scientists. in which we can help promote each other’s long-term success. Each observatory will benefit from this In attendance, we had representatives from Yerkes interconnection. My grandfather foresaw the need to Observatory, Observatory, Lick Observatory, network on a grand scale, both nationally and Griffith Observatory, , the internationally, to achieve his goals, and so shall we. Vatican Observatory in Arizona, and of course Mount Wilson Observatory. The first session took Sincerely, place in the 100-inch Telescope dome, which made a great conference room to discuss the future of historic observatories. While many (including Mount Sam Hale Wilson) are still doing cutting edge astronomical Chairman of the Board of Trustees research, they are all in need of public support to Mount Wilson Institute

REFLECTIONS 3 JUNE 2019 Trip to the Moon — "om page 1` kilometer in diameter. Shoemaker was able to begin reconstructing the order of events that created the craters In 1919, one hundred years ago, Francis Pease, Ritchey’s and other features on the lunar surface—lunar protege and the chief engineer of the 100-inch Telescope, stratigraphy. Eventually, he completed 50 maps, covering used the Moon as an easy target to test the newly finished most of the Moon visible from Earth.1 giant. Needing only short exposures to capture the Moon’s bright light, Pease began making an extensive collection of One of the early concerns with landing on the Moon (or 8 x 10-inch lunar plates that would be used to illustrate anything else) is the basic question: is there a firm spot to popular articles on the Moon for decades. It was, in some land on, or will one sink into a bed of dust? Way back in sense, America’s first “trip” to the Moon made possible by 1927, Mount Wilson astronomers Seth and the first truly big science project: the telescope funded by Edison answered the question. They had built a and John Hooker (who paid for the remarkably sensitive device that could measure the faint hundred inch mirror). heat from , planets, and the surface of the Moon, pioneering astronomy outside the visible spectrum—in the infrared. During an eclipse, they measured the surface temperature of the Moon as the Earth’s shadow swept across it. The temperature showed virtually no time delay in following the curve of radiation received from the Sun as the eclipse proceeded. From these results, they concluded that the thermal conductivity of the lunar material was exceptionally low, probably due to granular “pumice.” The layer, in Pettit’s estimation, was only about an inch thick.

Mount Wilson astronomer and historian, Allan Sandage, wrote, “An actual lunar landing 40 years later enabled astronauts to verify with their boots on the Moon’s surface what Pettit and Nicholson had surmised with their minds from Earth.” Had the Apollo mission planners read their paper in the Astrophysical Journal from the 1920s, they might not have worried quite so much about sinking into the dust. Using Mount Wilson images for reference, artist Roger Hayward sculpts a crater on a giant 38-foot section of the A less well known Mount Wilson lunar project was the Moon, an exhibit at Grifth Observatory created in the “Moon House.” It was the idea of geologist Frederick 193os. Walt Disney later commissioned Hayward to make , who came to the mountain in the mid 1930’s from similar models for the “Man in Space” television show and another branch of the Carnegie Institution, the Tomorrowland exhibits. Photo: LA Public Library Department of Terrestrial Magnetism. Wright eventually became known as the “Moon Man” and was, at the time of Surprisingly, these 100-inch Telescope images taken by his death in 1953, considered the foremost authority on Pease were still among the best decades later when the the Moon. (His daughter, Helen Wright was the author of moon was being mapped in advance of the Apollo Explorer of the , the biography of George Ellery missions. Planners needed to know the geology in detail to Hale, Mount Wilson’s founder.) select landing sites that would maximize the scientific In a popular science article written in 1935,2 Wright sums opportunities. So, in the early 1960s as the space race up the Observatory’s general feeling toward lunar heated up, the first “astrogeologist,” Gene Shoemaker of research: “In spite of (the public’s) general interest and the United States Geologic Survey, got to work making friendly feeling toward the moon, the president of the quadrangle, geologic maps of the Moon. Among his Carnegie Institution of Washington realized several years primary sources were the plates from Mount Wilson, ago that its presence in the night sky is resented by the stored in the vault at Carnegie Observatories in Pasadena. modern astronomer, especially the astrophysicist. Its light For his first map of lunar geology, Shoemaker chose the interferes with the photography and analysis of far distant, area around the giant crater Copernicus. Shoemaker’s faint celestial objects, such as stars, clusters and nebulae— paper on the map, the first geologic map of an incandescent masses of enormous size, radiating huge extraterrestrial body, featured an annotated image of the amounts of energy into space and of special significance crater taken by Pease in 1929. He had blown the because they yield information on the extent of the photograph up and could pick out craters as small as a universe and on the behavior and structure of matter

REFLECTIONS 4 JUNE 2019 under conditions of temperature and pressure not plates onto a spherical surface; the light had to be focused attainable in the laboratory.” Wright went on to say that, by a parabolic mirror placed 135 feet away—the same focal in comparison, the Moon “is a lifeless, inert mass, shining length as the Hooker Telescope. In his 1935 paper, Wright only by reflected sunlight” which held little interest for describes the target of the projected light: “a carefully the astrophysicist. In short, the Moon was getting little turned globe of bronze, 15-inches in diameter and coated attention because it was seen as boring. with magnesia powder. This coating furnishes a white diffuse reflecting surface. The image of the Moon formed Nevertheless, in 1923, the Carnegie Institution formed the on it is in all respects similar to the Moon in the relations Committee on the Study of the Surface Features of the of the surface features one to the other; in other words, it Moon, with Wright as chairman. The rest of the is a miniature Moon which can be photographed from any committee was composed of three Mount Wilson direction.” astrophysicists, Walter , Pettit, and Pease, and four other scientists, including the well-known astrophysicist, Wright realized that this “miniature Moon” could be made Norris of Princeton. One of their major permanent by coating a glass globe with a photographic goals was to create a definitive lunar topological map. For emulsion. It was not an easy thing to do, but the Corning this they needed to transform flat photographs of the Glass Company made 16 of the glass spheres and the moon into faithful spherical renderings. This would allow Eastman Kodak Company managed to apply the emulsion. craters and other features near the edges of the lunar disk The resulting globes, showing different phases of the to be viewed accurately without foreshortening. Moon, aided the mapping efforts and were used in exhibits and public talks. Today only four remain. This was the reason behind the Moon House, which Wright erected next to the 100-inch Telescope dome in In his paper, Wright describes the experience of looking at 1930. This temperature controlled building had to be very the Moon with a big telescope, presumably one on Mount long to house the necessary optics to project a sharp Wilson: “Viewed through a large telescope it appears to be image from light shining through Pease’s flat photographic only 200 or 300 miles away and details 500 feet apart can

Frederick Wright’s “Moon house” is visible behind the 100-inch Telescope dome roughly on the same footprint now occupied by the CHARA array beam equalization building. Photo: Carnegie Observatories

REFLECTIONS 5 JUNE 2019 have jeopardized the safety of the Apollo astronauts who had scant protection from the resulting particles and radiation. Little could be done once the astronauts were on the way to the Moon, but missions could be postponed if the Sun was looking particularly active just prior to an Apollo launch.

Padilla’s visit happened sometime after the major solar flare and CME that occurred on August 4, 1972. The Apollo missions happened to coincide with the years of peak solar activity, but for the most part solar cycle 20 was relatively tame. The size of the August 4th event however alarmed the mission planners. Had astronauts been on their way to the Moon, this solar storm would have given them a large radiation dose, enough to cause acute radiation sickness. So, up until the launch of the last lunar mission, Apollo 17, on December 7th, NASA undoubtedly One of the fe w surviving glass created by Frederick kept close tabs on the sunspot activity, checking in Wright on Mount Wi lson, in the Li brary at Carnegie frequently with Tom Cragg—perhaps Mount Wilson Observatories in Pasadena. Photo: Carnegie Obs. Observatory’s last contribution to lunar exploration. be distinguished under conditions of good seeing.” Having guided the 60-inch telescope with the Moon in the eyepiece, I would go even further. It gives you the sensation of flying above the surface in any direction with the ability to explore craters, mountains, and other features as if you were there — a trip to Moon, without the risks or discomfort of space travel!

And there are risks. Steve Padilla, the mountain’s longtime solar astronomer, remembers a particularly interesting tie between the Apol lo missions and Using Mount Wilson’s 150-foot Solar Telescope, Tom Cragg made this drawing of the Mount Wilson. Long monster spot responsible for the violent solar storm on August 4-5, 1972. Note the Greek before getting his job as a letter gamma (to its upper right), used to designate a complex region in which the positive UCLA researcher using the and negative polarities are so irregularly distributed that they can't be classified as a 150-foot Solar Tower bipolar sunspot group. These are the most likely to produce dangerous solar flares. Telescope, he and friends would visit Mount Wilson 1. To see Shoemaker’s beautiful geologic maps of the any chance they could. On one occasion in the fall of 1972, Moon, go to https://www.lpi.usra.edu/resources/ while he was visiting Tom Cragg, the chief solar mapcatalog/usgs/ astronomer at the time, he heard a telephone ring. It was a special phone on a dedicated line paid for by NASA for 2. Frederick Wright’s 1935 paper: https:// the sole purpose of checking the Sun’s activity during the archive.org/details/in.ernet.dli. manned space missions. A violent solar flare or a coronal 2015.27268/page/n99 mass ejection (CME) headed in the right direction could

REFLECTIONS 6 JUNE 2019 The Periodic Table Turns One Hundred and Fifty!

Saturday, August 17: Stellar Evolution & Origins of the Elements

To celebrate the 150th anniversary of Dmitri Mendeleev’s conception of the Periodic Table, our fourth evening lecture of the year will be delivered by our Trustee, Tim Thompson. He will explain how all the elements came to be. The story is intimately tied to how stars evolve and die. He will show how Mount Wilson Observatory astrophysicists played a major part in deciphering the lives of stars. Having spent three and a half decades as a docent on the mountain, explaining our rich history of astrophysics to countless visitors, and himself once a physicist at NASA’s Jet Propulsion Laboratory, Tim is uniquely qualified to bring the subject of nucleosynthesis down to earth. He also happens to bare a remarkable resemblance to Mendeleev — perhaps it is the beard.

Dmitri Mendeleev, creator of Mount Wilson Observatory Trustee and Docent, Tim Thompson, the Periodic Table in 1869. tells Edwin Hubble’s story in the 100-inch Telescope dome.

Mount Wilson Observatory's Periodic Table (used to help teach STEM students about spectroscopy) will be on display at the talk. Built to be transported to classrooms, part of the glowing noble gas column is shown to the left. The whole table has been wired so that the elements can be illuminated according to the astronomical process that created them.

The lecture starts at 5:30 and is followed by dinner, for cash purchase, provided by Pie and Burger in Pasadena, or bring your own. Then we will be opening up the 60-inch telescope for guests to look through until midnight. Once the largest in the world, this telescope was used by astronomer Harlow Shapley to map the extent of our and to determine our position in it, far from the center. The 6-inch Warner & Swasey refractor and other telescopes will also be available for viewing while visitors wait for their turn on the 60-inch Telescope.

For more information on Concerts, Lectures, and Tours please visit mtwilson.edu

REFLECTIONS 7 JUNE 2019 WELCOME, VISITORS! HOW TO GET TO MOUNT WILSON OBSERVATORY

Welcome hikers, bikers, star-gazers, visitors of all interests! The From the 210 freeway, follow (State Highway 2 Observatory is open from 10:00 a.m. to 5:00 p.m. daily on north) from La Cañada Flintridge to the Mount Wilson–Red Box Road; weekdays. On Saturday and Sunday the gates open earlier at turn right, go 5 miles to the Observatory gate marked Skyline Park, and 8:30 a.m. The Cosmic Café at the Pavilion is open on the park in the lot below the Pavilion. Visit the Cosmic Café at the Pavilion, weekends only from 10:00 a.m. to 5:00 p.m. and sells fresh- or walk in on the Observatory access road (far left side of parking lot) made sandwiches and Observatory memorabilia. about 1/4 mile to the Observatory area. WALKING TOURS WITH A DOCENT On weekends only two-hour public tours of the Observatory start at 11:30 a.m. & 1:00 p.m. Meet at the Cosmic Café to buy a ticket or go online. Guests on these tours are admitted inside the historic 100-inch & 60-inch telescope domes. Note that private tours are available all year long, weather permitting (see below). PRIVATE GROUP TOURS Group daytime tours are available on any date. Advance notice and reservations are required and a modest fee is charged. For more information, please visit www.mtwilson.edu/private-group-tours LOOK THROUGH THE TELESCOPES Mount Wilson’s historic 60-inch telescope and 100-inch telescope are available for public viewing of the night sky. For details, fees, etc., on scheduling a viewing session, see www.mtwilson.edu. PARKING AT THE OBSERVATORY The U.S. Forest Service requires those parking within the and the National Monument (including the Observatory) to display a National Forest Adventure Pass. For information, visit www.fs.usda.gov/angeles/. Display of a National Parks Senior Pass or Golden Age Passport is also acceptable. The $5 pass can be purchased at the mountain on weekends.