CHAPTER TWO

COMET-HUNTING AS A HOBBY

“I have the greatest admiration for a man or woman who discovers a comet, because I know of the hard and thorough work which the success implies.”

—W. R. BROOKS, the noted American comet-hunter.

To hunt for a comet in the ocean of space is as fascinating a hobby in its way as angling for a wily fish, requiring in either case an unlimited supply of perseverance, patience, and spare time. In place of fishing tackle one requires a telescope with an aperture of four or six inches, though excellent work has been accomplished with smaller instruments. It should be erected in a position commanding a clear view of the horizon either eastward or westward, as comets travel in the wake of the rising or setting sun. During the daytime a glance at a map showing the region of the sky to be examined in the evening will save an endless waste of time, to say nothing of the disappointment when the suspected object proves to be a nebula and not a comet. On the other hand, fuzzy-looking objects resembling comets have been mistaken for nebulæ when in reality they _were_ comets. For instance, in looking over Sir William Herschel’s list of 1,000 nebulæ and clusters, presented by him to the Royal Society in 1786, suspicion is aroused by the following entry: “Some of the shape of a fan, resembling an electric brush, issuing from a lucid point, others of the cometic shape, with a seeming nucleus in the center, or like cloudy stars surrounded with a nebulous atmosphere.” (_Philosophical Transactions_, Vol. LXXIV, p. 442.) As we shall see later on, the descriptions tally with the appearance of comets which have been photographed.

Nebulæ and clusters likely to be on the list of “suspects” have been charted in my father’s _New Star Atlas_, edition 1915, containing maps of all the stars down to the sixth magnitude (that is, all stars which can be seen with the naked eye), as well as the positions of nebulæ, clusters, and fainter stars which become visible with the aid of a small telescope. It is a compact, handy volume, serving as an excellent guide for the amateur comet-hunter in his rambles through starland in search of cometary prey.

Provided with a copy of this book, and allowed the privilege of using the Brashear (name of the maker), Comet-Seeker, which is stationed on the main roof of the Yerkes Observatory at Williams Bay, Wisconsin, U. S. A., the writer spent many a delightful evening during the summer of 1910, scanning the evening sky for celestial wanderers. Unable to resist the temptation to linger by the way in admiration of double stars, clusters, and nebulæ strewn along the highways and byways of starland, comets missed recognition.[3] Nevertheless, the evenings spent with the little comet-seeker were a source of unqualified delight, though no comet hove in sight.

The telescope of six inches aperture, easily handled, is inclosed in a sort of cabin which rolls on wheels. This can be pushed backward a certain distance, leaving the instrument out in the open air. Fortunately, the width of the cabin was such that it was just possible for the writer to catch hold of the rods on each side, drawing them backward the distance required; while shutting it was an easier matter, requiring as a rule a gentle push, sending the cabin back on the rollers provided for this purpose. Before doing so, however, the telescope was leveled and carefully wrapped up to keep it free from any moisture or dampness which might penetrate from the outside, and anyone who has passed a winter in Wisconsin knows something of the deep snowdrifts which must settle several feet deep in such an exposed site as the main roof of the Yerkes Observatory building. After the cabin has been closed, it is hooked at the sides and remains so until the services of the telescope within are once more required.

[Illustration:

THE COMET-SEEKER ON THE ROOF OF THE YERKES OBSERVATORY, AT WILLIAMS BAY, WISCONSIN ]

Then the cabin is reopened and the wrappings are removed from the telescope, which is turned in the direction of a specially selected star. This is kept in the center of the field of view, which is marked by the intersection of two threads made from a spider’s web. As there is no clockwork attachment, the telescope is guided by means of a small screw like a miniature wheel or helm, enabling the observer to pilot his or her way through the ocean of space. Then a keen search is made in the surrounding region, and if nothing in the way of a comet “stands revealed” to the searching eye of the telescope, another region is explored, so that a more or less extended expanse of sky comes under observation during the course of the evening. On one eventful occasion a supposed comet was glimpsed and its position duly charted with regard to neighboring stars. However, on reference to the star map the fuzzy-looking object proved to be a nebula. Supposing by any possibility the suspected object _had_ been a comet, this could have been proved beyond doubt by watching it for two or three evenings in succession. The presence of a comet can be detected as it slowly drifts against a background composed of the stars, while the nebula is at a distance so remote that an observer would have to watch for centuries before he detected any perceptible motion.

Nevertheless, there is a close resemblance between the hazy-looking objects known as nebulæ and comets when they emerge from obscurity. For this reason, they gave a great deal of trouble to Messier, a French astronomer of the eighteenth century. So keen was he on capturing comets that Louis XV nicknamed him “the Ferret of Comets.” Consequently, we can imagine his annoyance, after discovering a supposed comet, at finding it was merely a cloudy-looking object which he termed a nebula. He kept a careful record of these “embarrassing objects,” so that he might not be led astray by them again, and labeled them Messier 1, Messier 2, and Messier 3, in the order of discovery, and these are usually briefly recorded on star maps as M1, M2, M3, etc. In this way, Messier made a list of forty-five nebulæ, which he entered in a catalogue published at Paris in 1771. A century later (1871) the list had been enlarged by one hundred and three discoveries. For the listing of these “embarrassing objects,” as Messier termed them, we are greatly indebted, since in recent years photography has revealed the fact that they are among the most marvelous objects in the heavens.

With the assistance of a small two-foot telescope of two and a half inches aperture, magnifying five times, and with a field of view covering four or five degrees, Messier discovered thirteen comets. His first comet dates from 1760, and another French astronomer named Pons, who discovered a comet in 1802, joined him in the pioneer work of making a systematic search for comets. It is interesting to note that Pons was a doorkeeper at the Observatory at Marseilles, and, owing to the teaching and encouragement he received from Thulis, the director, he achieved phenomenal success as a comet-hunter. A third name must be added to the list of these enterprising searchers after cometary prey, _viz._, that of Montaigne, between whom and Messier existed a keen rivalry. The following story shows the importance attached by the latter to each comet captured.

It seems that on one occasion Messier, who had discovered twelve comets, was looking for his thirteenth, when his wife was taken seriously ill and died. While attending to her he was hindered in his search for the comet which was found by his rival, Montaigne. When some one sympathized with him about the loss he had sustained he said, “Alas! Montaigne has robbed me of my thirteenth comet!” Then realizing that he should be mourning the loss of his wife, he added the remark, “Ah! poor woman!” but he continued grieving for his lost comet.

Apparently Messier’s path was beset with difficulties, for in his book entitled _Planetary Worlds_ Breen tells us that on one occasion while Messier was walking in President Saron’s garden he was doubtless looking up at the sky on the chance of detecting a comet, when he fell into an icehouse, and was temporarily disabled. Later on, we are told in the same book, the revolution deprived Messier of his little income and every evening he was wont to repair to the house of the noted astronomer Lalande to replenish the supply of oil for his midnight lamp. The political storm made it necessary for him to remove to another neighborhood, “where he no longer heard the clocks of forty-two churches sounding the hours during the night watchings.”

Possibly his most trying experience occurred in connection with the expected return of Halley’s comet in 1758. It was first observed by a farmer named Palitzsch, living at Prohlis, near Dresden, who saw it on Christmas Day, 1758, with a telescope of eight-foot focus. He was an amateur astronomer possessed of keen sight, and was in the habit of searching the heavens with the naked eye, which seems to have given rise to the statement that he found Halley’s comet with the naked eye at a time when the professional astronomers were searching for it in vain with their telescopes.

Meanwhile, Messier had been carrying on a prolonged watch of the heavens, extending over the whole of the year 1758, but he did not actually get a view of Halley’s comet until January 21, 1759, when he observed it regularly for three weeks. He was the first noted astronomer to do so, but according to the account given by J. Russell Hind, in his book on _The Comets_ (page 41):

“Delisle, then director of the Observatory at Paris, would not allow him to give notice to the astronomers of that city that the long-expected body was in sight, and Messier remained the only observer before the comet was lost in the sun’s rays. Such a discreditable and selfish concealment of an interesting discovery is not likely to sully again the annals of astronomy. Some members of the French Academy looked upon Messier’s observations, when published, as forgeries, but his name stood too high for such imputations to last long, and the positions were soon received as authentic, and have been of great service in correcting the orbit of the comet at this (1835) return.”

The name of J. R. Hind, by the way, is the only English one included in the list of those who received a gold medal given to the discoverer of telescopic comets by Frederick VI, King of Denmark, who instituted the distribution of this award in the year 1835. The gold medal was also won by an American astronomer, Maria Mitchell, who discovered a comet, October 1, 1847, while engaged in making observations from the roof of the Nantucket Athenæum. When eighteen years old she was appointed librarian at the Athenæum, which position she held for twenty years. The roof of the building was her observatory. In 1865 she became professor of astronomy at Vassar College, a position she retained until her health permitted her to do so no longer.

The grant of the medal by King Frederick VI was discontinued after the death of his successor, Christian VIII, in 1848. The Vienna Academy of Sciences formerly gave a gold medal to the discoverer of every new comet, but this also was discontinued in 1880. Then Mr. H. H. Warner, a wealthy American, came to the rescue and offered a prize of two hundred dollars for every unexpected comet found by an observer in Canada or U. S. A., which brings us to the story told in the autobiography of the late Professor E. E. Barnard, one of the most successful competitors. He had nineteen comets to his credit, resulting in the erection of what he quaintly termed “The house that was built with comets.”

“Times were hard in the last of the ’seventies and the first of the ’eighties, and money was scarce. It had taken all that I could save to buy my small telescope. I had been searching for comets for upward of a year with no success, when a prize of two hundred dollars for the discovery of each new comet was offered (in 1880) by the founder of the Warner Observatory through the agency of Dr. Lewis Swift, its director. Soon after this it happened that I found a new comet and was awarded the prize. Then came the question, ‘What shall we do with the money?’ After due deliberation it was decided that we [referring to Mrs. Barnard] would try to get a home of our own with it. I had always longed for such a home where one could plant trees and watch them grow up and call them our own. So we bought a lot with part of the money, which was on what was afterwards called Belmont Avenue, but which was not then even a road. It was hard to find the lot after it was bought, for it was out in the open common. The place was in the midst of a scattered settlement of negro shanties, where the negroes had ‘squatted’ after the war, though on beautiful rising ground which I had selected in part because it gave me a clear horizon with my telescope.

“After some saving and some borrowing, and mainly a mortgage on the lot, we built a little frame cottage where my mother, my wife, and I went to live. Those were happy days, though the struggle for a livelihood was a hard one, with working from early to late for a bare sustenance (and the hope of paying off the mortgage), and sitting up all the rest of the twenty-four hours, hunting for comets.

“We could only look forward with dread to the meeting of the notes that must come due. However, when the first note was due a faint comet was discovered wandering along the outskirts of creation, and the money went to meet the payments, and this continued after we had gone to other scenes. The faithful comet, like the goose that laid the golden egg, conveniently timed its appearance to coincide with the advent of those dreaded notes. And thus it finally came about that the house was built entirely of comets. This fact goes to prove the great error of those scientific men who figure out that a comet is but a flimsy affair after all, infinitely more rare than the breath of the morning air, for here was a strong compact house, albeit a small one, built entirely out of them. True, it took several good-sized comets to do it, but it was done, nevertheless.”

In connection with the prize offered by Dr. H. H. Warner, Professor W. H. Brooks discovered twenty comets; Barnard, nineteen, as already stated; Perrine, thirteen; and Swift, eleven. Awarding this prize was given up after a while, but the idea was again revived by a wealthy American, the late Mr. J. M. Donohoe, in the year 1890, with the result that a bronze medal is now presented to the discoverer of any new comet, on the report of a committee of the Astronomical Society of the Pacific. There were two awards for the year 1923. Comet A was discovered independently by Sr. Dr. Arturo Bernard, Colmenarejo, Madrid, Spain, on October 11, 1923; and by Alexander D. Dubiago, of Kasan, Russia, on October 14, 1923. The medal was awarded to each of these two discoverers. On November 10, 1923, Mr. W. Reid, of Rondebosch, South Africa, who has been awarded several of the medals for his discoveries of comets, added another to his list of captures.

Regarding the ease with which comets may be discovered in the clear skies of America, Professor H. H. Turner, in his lecture on Halley’s comet, given before the British Association in 1908 at Dublin, referred to a meeting which took place at Albany, New York, of the Board of Visitors. A discussion arose as to the value of some desk work which the director was carrying on, as compared with the discovery of a comet, which it was suggested would surely add to the reputation of the observatory. Professor Boss (the director) promptly remarked that nothing was easier, if they would sanction the outlay of certain sums of money to be used as salary for a person of average intelligence, while devoting himself to the search.

“The challenge was accepted on the spot,” remarked Professor Turner, “the money subscribed, the searcher set to work, and within the allotted time a fine comet was found. Professor Boss undoubtedly took a certain risk in undertaking to catch a comet, just as a man who would undertake to catch a fish within a definite time. But he was anxious to indicate his views of the relative importance of different kinds of work, and deserved the success he ventured to count upon.”

One wonders if this was the occasion referred to when it is said that the comet-hunter, after a preliminary search for a comet, returned to the room where the Visitors were awaiting his report, announcing that he had discovered a comet in such and such a part of the sky. It was immediately claimed by Professor Barnard, who was present on this occasion, as one that had already been discovered by him last spring, or a year or so ago, as the case might be. After this had occurred two or three times, it is said, the comet-hunter remarked to Professor Barnard, “Why don’t you keep your comets chained?” However, it may be as well to take this story _cum grano salis_.

The cloud-laden skies of England are not encouraging, as far as comet-hunting is concerned. It may be possible, when the moon is absent, to get a glimpse of a comet low down in the vapors after sunrise or sunset, if the chances are favorable. Then follows a week of cloud and misty skies during which period the comet has vanished. For this reason the discovery of comets in England is rare, but all the more credit to those who eventually succeed in making a capture.

Our veteran comet-hunter is Mr. W. F. Denning, of Bristol, who has specialized in the observation of comets and meteors. In his book on _Telescopic Work on Starlight Evenings_ he gives an instance of two experiences he had in the year 1881, showing how he missed one comet, but succeeded in finding another, just before sunrise, when comet-hunting is not nearly as attractive, one imagines, as in the evening.

It seems that on July 11, 1881, after a night’s observation of the stars, Mr. Denning, just before daylight and preparatory to ceasing work, looked in the direction of the constellation Auriga, the Charioteer. The idea occurred to him that it might be worth while to sweep the surrounding region with his comet eyepiece, but he hesitated, not thinking the prospect sufficiently inviting. There is a well-known saying that he who hesitates is lost, and on this occasion Mr. Denning undoubtedly missed an opportunity for finding a comet. Three nights later a bright comet in Auriga was discovered by Schaeberle, an American astronomer at Ann Arbor, Michigan!

That same year, on October 4, Mr. Denning had been observing the planet Jupiter before sunrise, when once more he hesitated as to the advisability of making an attempt at comet-seeking, but, profiting by his former experience, he made use of the comet eyepiece with good results. To quote his own words—

“at almost my first sweep I alighted upon a suspicious object which afterwards proved itself a comet of short period,”

which means that it is a frequent visitor to the neighborhood of the sun. These facts are encouraging, and still more so when we remember that Kepler said, “there are as many comets in the sky as there are fishes in the sea.”

The first woman to discover a comet was Caroline Herschel, the sister of the famous astronomer, Sir W. Herschel, and she had eight to her credit. In her diary, which has been most carefully preserved by Miss Francesca Herschel at Observatory House, Slough, there is an account of her first discovery which occurred on August 1, 1786. During the absence of her brother in Germany she availed herself of the opportunity to make use of a small Newtonian telescope he had given her, in “sweeping the skies.” Her “sweeper,” as she termed it, was of 27-inch focal length, a power of about 20, and a field of view 2° 12′.

Miss Herschel had been observing nebulæ when she saw what she believed might prove to be a comet. At one o’clock on the morning of August 2 she made the following brief note in her diary: “The object last night _is_ a comet,” and she wrote to Dr. Blagden of the Royal Astronomical Society, asking him to take the comet under his protection “in regard to its right ascension and declination,” which correspond to latitude and longitude of a place on earth. The right ascension of a heavenly body is measured eastward along the celestial equator, from the vernal equinox to the hour circle on which the object lies. Declination of a heavenly body is its distance north or south of the celestial equator, measured on a great circle passing through the pole and the celestial body.

Caroline Herschel sent drawings she had made, showing the position of the suspected object with regard to certain stars in the same field of view, to Dr. Blagden. He was thus enabled to locate the comet and confirm her observation. When this discovery of a comet was followed by seven more, Caroline Herschel succeeded in making for herself a European reputation for what was called “her eccentric vocation.”

In 1828 she received the gold medal of the Royal Astronomical Society, and in 1835 was elected an honorary member thereof. The personal interest she took in her cometary captures is evidenced by a neat little packet found among her papers after her death, containing the account of her discoveries. It was labeled “Bills and Receipts of my Comets.” This also has been carefully preserved by Miss Francesca Herschel (the granddaughter of Sir William Herschel) who showed it to the writer during the summer of 1922.

Searching for comets is not part of the defined programs of observatories, as it involves an immense amount of time with results which only present themselves at intervals. However, when an amateur succeeds in discovering a comet and has made known the fact to a professional astronomer, the latter completes the work of computing its orbit and other elements, which is not usually undertaken by the discoverer, unless he has the requisite mathematical knowledge.

Yet it is advantageous, if he possesses a ring micrometer (an instrument used for the measurement of small angles), to learn how to make use of it during the first few observations, which are usually made before the comet has been seen elsewhere. These observations, if precise, will prove of the greatest value. The news of the discovery of a comet should be sent at the first opportunity to the director of the nearest observatory, who will communicate with the director (Elis Stromgren) of the Bureau Centrale Astronomique de l’Union Astronomique Internationale, Observatoire de Copenhagen, from which center it will be sent broadcast all over the world. The discoverer will then experience the delight of having a comet named after him, which he can claim forthwith as his own individual celestial treasure trove. As a matter of fact, newly discovered comets are now usually referred to by their date and order of discovery, as Comet 1, 1924, saving much confusion as to the name of the actual discoverer. This was exemplified in the case of a comet found by Pons in 1819 (III of that year), which Encke showed to be revolving in an ellipse with a periodic time of three and one-half years. Hence its name of Encke’s comet. It was again renamed after Winnecke, who rediscovered it in 1858, but actually he had no more claim to the title than Caroline Herschel, who discovered it in 1795—her seventh comet—or Méchain by whom it had been previously seen in January, 1786.

The majority of comets travel in an ellipse, and those of short period, like Encke’s comet, make short journeys and may be considered frequent visitors to the neighborhood of the sun. Others are long-period comets, such as Donati’s (described in the following chapter), since it requires nearly two thousand years for the round trip. Finally there is a third class of adventurous comets which dash in from outer space, swinging swiftly round the sun in the focus of its curve, and darting off again with no prospect of returning, since they cannot possibly get round the other focus. Whence they have come or whither they have gone, no man knows! They are like the sparrow referred to in a simile used by a courtier in the days of King Edwin, who compared its fleeting visit to the life of a man:

“It is as a sparrow’s flight through the hall when you are sitting at meat in winter tide, with the warm fire lighted on the hearth, but the icy rain storm without. The sparrow flies in at one door, and tarries for a moment in the light and heat of the hearth fire, and then flying forth from the other, vanishes into the wintry darkness whence it came.”