te voLUMEtd NO3 + AUTUMN 19I}9 THE NEWSLETTER I Patt of one discovery ptate of Pluto in the constellation Gemini takzn on January 29, D3A. The arow points to Plttto (about 15th magnitude). The bight star is Delta Geminorum. South is at the top and west at the left. (photo coufiesy Clyde Tombaugh) Discoverer of Pluto to Speak Dr. Hazel Ross A special treat is in store for us this Fall when Dr. Ctyde Dr. Tombaugh was born and raised on a farm, first in Tombaugh, discoverer of the planet Pluto, will give the Illinois and later in Kansas. tnspired by an uncle who was Chesley Bonestell Memorial L,ecture on September 23. As something of an amateur astronomer, and encouraged by one contemporary writer has pointed out, "More people have his father, he developed a keen interest in astronomy as a walked on the moon than have discovered planets. In fact, teenager. [,ater, using a f-inch reflector he had made only two other individuals in history have actually discovered himself, he studied Mars and Jupiter and sent drawings of new planets. Dr. Tombaugh is the third, and is still with us." what he had seen to Lowell Observatory in the hopes of obtaining a job. It turned out that the Lowetl astronomers Dr. Tombaugh had just turned 24 when, on February were looking for a young, aspiring astronomer to undertake a 18, 1930, he made the momentous discovery that rocked the search for a new planet beyond Neptune using the world. He had been working at the Lowell Observatory for observatory's new 13-inch camera. Impressed by the work just over a year. Tombaugh had done all on his own, they hired him, and the rest is history! It is interesting to note that on September 5, 1989, for the first time since its dismvery Pluto reaches perihelion-the Dr. Tombaugh, at 83, continues to radiate his point at which it is closest to the sun (29.656 astronomical enthusiasm and excitement for astronomy. He is Professor units away). The next perihelion won't occur until 2236! Emeritus at New Mexico State University and his backyard Pluto's closest approach to earth will come in May 1990. contains a remarkable collection of telescopes made with his continued Saturn Occults a Bright Star *' Stew Hobson * A once-in-a-lifetime event occurred in the late wening of Sunday, July 2, and lasted until the early morning of Monday, July 3. Beginning about 11:00 p.m. PDT, the planet Saturn and its rings occulted the 5.4 magnitude star 28 Sagittarii. Several members of the MIRA Amateur Astronomer Group were on hand at Bob Webb's Tularcitos Observatory to witness and time this remarkable event' Steve Butler and his wife, Ray Dyck and Brenda Aronowitz, Dick Spaulding, Mitchell Thompson and I all made the drive up to our favorite observing site in the hills above Carmet Valley- The various members of the observing team started arriving at about 9:fl) and by about 9:30 everyone was set up and ready to go. With somewhat more than an hour before the occultation began, we.started scanning the skies for objects of interest. As the sky got darker, some of the fainter objects in the southern sky grew steadily brighter; the Iagoon Nebula in particular was quite memorable. Two or three of us even managed to identif lJranus, a short distance away foom Saturn in the sky. As the time for the beginning of the occirlation drew close, Mitchell tuned to WWV for the timing signals and Clyde Tombaugh at the guiding qqiece of the l3-inch turned on his tape recorder. Everyone grew silent as we tilrnq" (which took the discovery plaus of Plato) at LoweV littened to the signals being broadcast orrer the radio. While Obsertatory in l9jt. (Photo couttery of Clyde Tonbaugh) keeping a steady view of Saturn, we tried to anticipate when Saturn's orrter ring would actually start to obscure the star, * and all our attention became focused simultaneously on the star and the outer ring of Saturn, ever so sloflly approaching ''[here she goes!" and own hands The 9-inch telescope that got him the job at each other. At last everyon€ chorused, Lowell Observatory is still in use and still being modified! the occultation had begun. process In his ta[q Dr. Tombaugh will talk about the For the better part of the next hour everyone intently show slides of the and equipment used to find Pluto and will peered into his eyepiece as 28 Sagittarii made its way behind prospect of actual dismvery plates. He will also discuss the Saturn's A ring, still shining through this relatively reaches of the solar finding a tenth planet in the far outer transparent ring, emerging with increased brightness into the system. famous Cassini division, vanishing totally for almost 20 After the talk, Dr. Tombaugh will be available to sign minutes as it crossed behind the B ring, flickering irregularly special posters showing the discovery photographs. The as it passed behind the very tenuous C ring, emerging briefly before posters cost $20 and alt proceeds go to benefrt the Clyde in the gap between the C ring and Saturn's dish Tombaugh Scholars Endowment Fund which provides funds finally vanishing altogether behind the disk itselt for outstanding young astronomers to do research. Approximately 50 minutes had passed since we all had noted the star's frrst dimming. Thisis an unparalleledopportunityto meetone of theZ)th century's most famous frgures. Only one or two hearty souls had the stamina to wait around until 28 Sagittarii emerged from the other side of The lecture will be held at the Sister Carlotta Performing Saturn's disk about two hours later. Honever, Mitchell duly Arts Center at Santa Caalina School at 8:00 p.m. Special sent offour timings and obeervations for the "inbound" leg to seatingwillbe reserved for the Friendsof MIRA the International Occultation Timing Association. Everyone continued ageed that this viewing experience had been well worth the So by searching for galaxies from the list of radio effort and not one we would soon forget. Many thanks go to sour@s, astronomers could find big, luminous galaxies. For Mitchell for spearheading the observing effort and to Bob distant galaxies, only these brightest galaxies can be seen from Webb for graciously providing his obserrratory grounds as an Earth anyway. observing site. Without a guide, finding the distant galaxies would be like trying to pick the San Francisco Giants' fan out of a picture of a crowded Southern California beach. Without some identiSing mark like a baseball cap, it would be an Those Distant Galaxies, overwhelming task. Far, Far, Away. Astronomers must intelligently expend their resources. There is a limit to how many objects they can study. Professor * Dennis Mar * Spinrad and his students have studied the physical characteristics of a couple hundred very distant gala:ries in a As the movie says, distant galaxies are far, far away. We third ofa career. see them as they were a long, long time ago. For MIRA's June public lecture, Dr. Hyron Spinrad described his Yet even with the radio sources as a guide, the job is research on these objects. In between the facts about radio daunting and requires persistence. Finding the right object galaxies, expanding universe, and Doppler shifts, he spoke and recording its spectrum might require ten nights of about astronomy as a human enterprise. observing spread over several months. Professor Hyron Spinrad is a faculty member at the To do their work, researchers at the University of University of California, Berkeley. Stew Hobson, MIRA's California have Lick observatory on Mt. Hamilton in the east amateur observer coordinator, sfudied asffonomy with Dr. San Jose hills. It is close and familiar but the nearby Spinrad. Both said they were very young at the time. metropolitan lights disrupt stellar spectra with ortra sodium Professor Spinrad presentation was the annual Dolph Tewes and mercury lines. Memorial [.ecture. Darker skies can be found at places such as Cerro The universe is expanding. The distant galaxies move Tololo in Chile. With these observatories the problem can be away from us at the greatest speed. Since light takes so long getting there with astronomers doing their ovm versions of to reach us from these galaxies, we see them as they were "planes, trains, and automobiles." billions ofyears ago. The study of distant galaxies gives us clues to fundamental questions such as the origin of galaxies, the large scale organization of the universe, and the ultimate fate ofthe universe (expansion, steady state, or collapse). It is not obvious which galaxies are the furthest away. Galaxies are not rare. In an area of the sky the size of the moon, modern detectors can find 40 to 1m thousand galaxies. Galaxies are social animals: find one and you will find another. The challenge is to uncover the distant galaxies from among the others. Fortunately, radio astronomer. on provide hints. It is difEcult to pinpoint radio sources because radio waves are much longer than light waves. But by the 1960's, radio astronomers had developed their technique to the point where other astronomers could begin searching in the visible spectrum for the sources of these radio waves. It was found that some of these radio sources were galaxies. And these galaxies were special because they were both radio emitters and very luminous. Why strong radio Dr. Ilyron Spinrad answere questions after his talk on distant emitters? Perhaps "a black hole at their center or a galaxies.