THERE is a great deal of truth in the cliche that the day of significant contributions by amateurs in science has passed, but it is probably less true in astronomy than in most other sciences. In astronomy, perhaps more than in any other field, the dividing line between the amateur and the professional is still rather thin and hard to define. Amateurs and professionals hobnob in the same organizations, work on some of the same kinds of problems and often are equally innocent of remuneration for their work, or vice versa. It is also a fact that amateurs have made many important contributions to astronomical knowledge in the past half-century. Nearly everything we know about the moon's surface and that of the planet Jupiter is due to the work of amateur observers; they have also been responsible for the discovery of many comets, meteor showers and novae. In addition, as regular readers of this department know, amateurs have contributed in no small way to telescope optics, astronomy's servant.

The history of amateur astronomy is summed up in the history of a few amateur societies. One of the earliest was the Astronomical Society of France, founded in 1887. It set a pattern for such organizations by admitting professionals as well as amateurs; it now has several thousand members. In 1889 a group of professionals and amateurs in the Pacific Coast States organized the Astronomical Society of the Pacific. This society became increasingly professional, however, and today its 800 members include many specialists, and its journal, called The Publications, is largely technical.

The most active and serious-minded of the amateur groups is the British Astronomical Association, founded in 1890. From the outset it carried on organized, systematic observations. Within 10 years of its founding it had 1,169 members and had already published 32 "memoirs" on the sun, planets and moon, with many detailed drawings of sunspots and planetary and lunar features. Today its 1,800 members are divided into more than a dozen working sections, each specializing in a particular investigation such as the sun, the moon, a planet, comets, meteors, the aurora and zodiacal light, variable stars, photography, instruments, computations and astronomical history. Although amateurs cannot do difficult astrophysical research, the members of the British group have published a great number of memoirs describing long, patient investigations of astronomical subjects within their reach; notable among them are minutely detailed maps of the moon by the late Walter Goodacre and more recently by H. P. Wilkins.

The founding of the British association was followed in 1903 by the formation of the Royal Astronomical Society of Canada, a federation of amateur astronomers' clubs in 11 Canadian cities. These clubs do little organized observing but meet to hear lectures by professional astronomers or the reading of members' papers, and the Society publishes a periodical called The Journal and an annual Observer's Handbook. There are now 1,700 members, including 300 in the U. S.

In the U. S. amateur astronomy made a slower start. The early files of Popular Astronomy, a publication founded in 1893, show that for many years professional astronomers worked hard but without much success to' build up a body of amateur astronomers in this nation. Then in 1911 the American Association of Variable Star Observers was founded to help the professionals keep watch on some of the 600 variable stars. Since 1911 the diligent members of this group have provided astrophysicists with more than a million observations of variable stars—one of the most solid contributions by amateurs to astronomy. Recently the Association has sponsored organized observation of sunspots and a lookout for bright novae. It has also done cooperative observing with the American Meteor Society, another amateur group founded in 1911.

Since 1925 local groups of amateur astronomers have been forming all over the country, and after World War II Charles A. Federer, Jr., of Harvard University, who had long been active in popular education in astronomy, organized these groups in a federation called the Astronomical League. It now has 56 member organizations and 3,389 members. In 1947 another new society, the Association of Lunar and Planetary Observers, was formed to make systematic observations of the moon and planets, it publishes a periodical called The Strolling Astronomer.

It would be misleading to suggest that the principal purpose of the amateur astronomy movement is to contribute important new research and discovery to the science. Although the amateurs observations have been helpful to the professionals, few amateurs are equipped to make basic discoveries of new knowledge in modern astronomy. The amateur in this field, as in any other, finds sufficient justification in the pleasure and personal enlightenment afforded by the pursuit of his hobby, whether at the eyepiece of a telescope, at the workbench, in an armchair or in the sociable company of colleagues with a kindred interest.

This is particularly true of the many thousands of amateur astronomers whose chief interest is in making their own telescopes, and who for a quarter of a century have been the special concern of this department of SCIENTIFIC AMERICAN. Few of the amateur telescope makers have yet discovered new worlds with them. Probably most have found more satisfaction in making telescopes than in using them; the first telescope is barely started before they are already planning the second. By and large the telescope maker is not an observer. This may be regrettable, but the work of the telescope makers has not been without profit to astronomy. It has made an appreciable indirect contribution to the science through its contributions to precision optics. Some of the amateurs have gone on to become professionals, and to design new types of optical instruments for astronomy.

The history of the amateur telescope-making movement may be of some interest to all who are interested in science and in broadening the understanding of science among laymen by enlisting a more widespread amateur participation. The fascinating but latent possibilities in the art of telescope making were discovered quite accidentally by this magazine just 25 years ago. Before that time the art had never had more than a handful of followers, but as information about it was made widely available through the pages of SCIENTIFIC AMERICAN and the book Amateur Telescope Making, tens of thousands of persons eagerly seized upon it as a most absorbing pastime and ultimately developed it to a full-fledged nationwide movement.

Had an unknown borrower in the New York Public Library one day in 1925 deposited Volume 29 of Popular Astronomy on the book-return desk one minute earlier or one minute later, this history of telescope making might not have been written, at least not by this author. As it was, the writer, who happened to be present at precisely that moment, idly picked up the volume before it could be returned to the library's stacks and came upon an article by Russell W. Porter on the making of reflecting telescopes. He recalled that his father, Charles W. Ingalls, had once said many years before that there were not 10 men on earth capable of making telescope mirrors and lenses. The writer sat down and read the article with fascination. He went home determined to attempt to make a telescope of his own, and therefrom grew an unforeseen sequel of events.

The seed had actually been planted many years earlier. Porter himself had discovered telescope making in 1911 through a copy of Popular Astronomy sent to him by a friend. The periodical had a short note about a telescope made by Leo Holcomb of Decatur, Ill. (who in turn had been prompted to undertake his project by reading an article with some scanty instructions for telescope making by John Mellish in Popular Mecanics in 1907). Porter wrote to Holcomb for further information, and with the help of a book on glass working began to make reflecting telescopes. By 1925 he had made 10 mirrors. The writer, after reading Porter's article, purchased a mirror blank and communicated with Porter, then living in Springfield, Vt. Porter soon announced that he was coming to New York on business and suggested a meeting.

At six o'clock one spring evening in 1925 we sat down to two-inch mutton chops in Brown's Chop House on Broadway. We arose from our chairs only in time for Porter to catch a midnight sleeper to Vermont–after six solid hours of talk about telescopes! Porter became so absorbed in the subject that in the midst of dinner he stood up in the crowded restaurant, thronged with theatre goers, and gave me a demonstration of mirror grinding with the makeshift tools at hand. Using two inverted saucers on the dinner table, he demonstrated various grinding and polishing strokes, ordinary and extraordinary, with a quiet running commentary. While the fascinated restaurant diners, to whom Porter was completely oblivious, stopped dining to watch, uneasy floor managers hovered indecisively over the performance, apparently wondering what kind of emergency vehicle should be summoned.

During the evening Porter proposed that an attempt be made to spread the telescope-making virus through SCIENTIFIC AMERICAN. Soon after he returned to his Vermont home, he renewed the suggestion, writing: "I have held a meeting of the telescope makers of Springfield to set a date for your visit. We have, after due consideration of the moon's phase, configuration of the planets' horoscopes and astrological incantations, found that the 13th of June seems the most auspicious for the night at Stellafane on the mountain. A little grinding experience before then will give you more appreciation of the stuff you will hear discussed here."

A somewhat over-dramatized account of the events of that June night was published in the November, 1925, issue of SCIENTIFIC AMERICAN. We thought that perhaps half a dozen readers might show some interest. Actually we had 368 immediate requests for instructions in the art of telescope making. Early in 1926 the magazine began to publish articles of instruction by Porter, and eager readers all over the country fell to work grinding their first telescopes. A series of accidental events, which had brought together a reliable source of instruction, a means for its dissemination and a catalytic agent, had revealed an unsuspected hunger for creation to which about 50,000 amateur-made telescopes have since been fed without reducing the hunger.

Very soon all amateur telescope makers with known addresses in the Northeast States received printed invitations to a meeting at Stellafane on July 3, 1926. A group photograph still in existence reveals that on that date 17 guests assembled behind Porter's Springfield telescope in front of Stellafane, shown in one of the drawings on page 109. This was the first of 17 such conventions, some of which brought as many as 400 pilgrims to the crowded mountain top at imminent risk of mutual suffocation, for Stellafane is only a little wooden house on top of a mountain that is only a hill. Unfortunately the conventions eventually outgrew the capacity of the Stellafane retreat, nestling in a grove of aromatic black spruces, and the amateur astronomers now convene in cities or on campuses.

The invitations. to the second Stellafane convention in 1927 read: "No formal program but a chance to talk over your problems." It had been recognized that the amateurs wanted most of all to become acquainted, hence no attempt was made to weary the visitors by aping the formal programs of established societies, and this set the keynote for future Stellafane conventions.

By 1928 the movement was well amarch. In that year this department, then called "The Back-yard Astronomer," was started as a regular feature of the magazine: The first, 103-page edition of Amateur Telescope Making had vanished and 6,000 copies of a second edition of 285 pages were printed. Clubs of amateur astronomers were being formed in local communities. The skill of the amateur telescope makers did not yet match their enthusiasm; most of their products were too light and shaky, but progress was being made.

When in 1930 the Lowell Observatory in Arizona announced the discovery of the planet later named Pluto, the press stated that its image had been found on the plate by Clyde Tombaugh, "who once had made a telescope." This hint led to the disclosure that Tombaugh had started as an amateur. The telescope referred to, his third, had been mounted by his father on parts adapted from a straw spreader, a cream separator and an old car. "Its optical performance," according to Tombaugh, "was most gratifying." Appointed as a professional to the staff at the Lowell Observatory and assigned to. the search for an outer planet, Tombaugh examined two million images with the blink microscope and within a year succeeded in finding Pluto. Tombaugh is one of several professional astronomers now at large observatories who graduated from the ranks of the amateur telescope makers.

In the depths of the economic depression of the 1930's men who were out of work turned to telescope making as an inexpensive form of fun and as a morale-preserver. And in World War II the amateur telescope making movement made a material, practical contribution to our military needs. The war found this nation short of roof prisms for gun sights—one of the most difficult prisms to manufacture–and even of trained personnel who could make them. An amateur telescope maker, Fred Ferson of Biloxi, Miss., who had mastered the difficult art, undertook to instruct other amateurs. Through this magazine, which coordinated the project and distributed his instructions, he taught 100 advanced amateur telescope makers how to make roof prisms. Working in spare hours in their home workshops, about 15 of these amateurs produced more than 30,000 roof prisms, And in Texas a graduate of the amateur telescope making hobby produced another 30,000 in his plant. It turned out that the amateurs' prisms excelled those of professional manufacturers by a wide margin in quality of workmanship, no doubt because of the amateurs' pride in their skills and the fact that large manufacturers could not arouse equal pride of workmanship in their employees.

Amateur telescope making is now in its second generation of followers. It is clearly destined to a permanent place as a hobby that attracts those who enjoy the challenge of its exceptional difficulties.

The Society for Amateur Scientists (SAS) is a nonprofit research and educational organization dedicated to helping people enrich their lives by following their passion to take part in scientific adventures of all kinds.