As seen at Newcastletown Moor, January 28, by the author
]
Nevertheless, despite a few tragedies consequent upon fear at the
comet’s near approach, the lurking dread of evil it might have had in
store for us was considerably less on the occasion of the return of
Halley’s comet in 1910, than was usual in the gloomy, prognosticating
period of the Middle Ages. Yet certain events occurred which made some
people wonder if there was not a kernel of truth in the so-called
portents after all. For instance, during the month of January (in the
eventful year 1910) the so-called Daylight comet—a totally unexpected
visitor to the sun’s domain—blazed out in the evening sky and the people
of Paris saw its reflection in the flood which threatened to destroy
their city. In May, while Londoners were watching for Halley’s comet,
which proved to be a very disappointing spectacle in this part of the
world, the body of King Edward the Seventh lay in state at Westminster.
“What wonder,” as Mr. Arthur R. Hinks observes in his book entitled
_Astronomy_, “that the imagination seizes upon these deplorable
coincidences and the fear of comets dies hard among us?”
Tennyson thus refers to Halley’s comet in his poem “Harold”:
“Lo! there once more—this is the seventh night
You grimly-glaring, treble-brandished scourge of England.
· · · · ·
Look you, there’s a star.
· · · · ·
It glares in heaven, it flares upon the Thames,
The people are as thick as bees below,
They hum like bees—they cannot speak—for awe,
Lord Leodwin, dost thou believe that these
Three rods of blood-red fire up yonder mean
The doom of England and the wrath of Heaven?”
Milton in “Paradise Lost” compares Satan to a comet:
“That fires the length of Ophiuchus huge
In the Arctic sky, and from his horrid hair
Shakes pestilence and war.”
It has been suggested that the poet was doubtless referring to the comet
of 1618, which was held responsible for the great Thirty Years’ War.
Milton was only ten years old at the time, but the impression made on
his mind by this magnificent comet with a train 104° long (or over
twenty times the distance separating the pointers in the constellation
of the Great Bear), “may well have lasted until he wrote the above lines
as a man of fifty.”[1]
Elsewhere, in “Paradise Lost,” Milton refers to a comet as the
brandish’d sword of God:
“... before them blaz’d
Fierce as a Comet: which, with torrid heat,
And vapours as the Lybian air adust,
Began to parch that Temperate clime.”
According to the translation by Longfellow, Dante in his “Paradiso,”
Canto XXIV, refers to comets as “souls beatified.”
“Thus Beatrice: and those souls beatified
Transformed themselves to spheres on steadfast poles
Flaming intensely in the guise of Comets.”
Turning to the _Avesta_ writings, we find that the Parsees of ancient
Persia classified comets as parihs, or fairies. _Pari_ is the Iranian
word for fairy, and is derived from the word “par,” meaning to tempt, to
enchant. The English word “fairy” also comes from a similar root,
“fier,” to enchant.
Nevertheless, these cometary fairies are not the dainty beings of
English folk-lore, but are described in the _Avesta_ as “ill-born
fairies,” their appearance in the sky inspiring terror, since they are
supposed to bring disease, calamity, and death in their wake. In the
picturesque language of the Persian writer, “the distress of the earth
becomes as that of a sheep when a wolf falls upon it.”
The following quaint account of the influence of a comet is given in the
_Avesta_.
“A hairy comet appeared in the year 662, Hijri, and the increase of
the splendour of the world was in Leo. The strange thing was that it
appeared to be of the proportion of the head of a big man and
emitted steam from the front. It passed over the countries of Tibet,
Turkestan, China, Kashgar and remained visible for 85 days. In all
these countries there arose rebellions. In Khorassan calamities of
thunder and lightning and other such phenomena appeared.
“Many years and many months had passed over this event, and then in
803, a tailed comet appeared in the zenith of Constantinople.
Astrologers informed Timur that from what the wise and the
experienced have said, it appears that an army coming from the
direction of the east will be victorious in that country, and a
general from that country will assist him. Timur (literally: the
illuminator of the face of fortune), who was always expecting an
invasion of the country, but whose companions of poor intelligence
did not acquiesce, attended to that prediction and convinced the
great and small of his court, of the truth and insight of the
star-seers. The learned in the mysteries of the heavens are
convinced of this, that if the comet appears within the boundaries
of a country, its king dies. If it is inclined towards the boundary,
the country of the governor passes away from his hands, and plague
and disease add to the afflictions of the country.”[2]
Some of the Pahlavi books refer to a comet as “the thievish Mushpar
provided with tails.” The comet was classified as an evil spirit in
company with planets and meteors which wandered hither and thither;
while the sun, moon, and fixed stars were considered good spirits,
because they were always to be found at appointed times in their places
in the sky.
In the mythology of China and Japan we find that comets were supposed to
be celestial representatives of every country on the earth, and occupied
the important position of ambassadors journeying from one celestial
region to another, and giving forecasts of terrestrial events of
importance. For this reason, careful records were kept of the dates of
their appearance and the paths along which they traveled, thus enabling
astronomers of to-day to trace back the path of Halley’s comet, for
instance, to a very remote era. Whatever the motive that prompted the
accumulation of records, they have proved of the utmost value.
Comets are called “broom stars” in China, a name derived from the form
of their tails, which have the very prosaic name of brooms (sui or
soui). A comet without a tail was referred to as merely a star, or a
guest star, from its visiting the provinces and taking up its abode in
different places, as at an inn.
“Their home was in the vestibule of the celestial palaces; there,
under an invisible form, they awaited the order of departure,” says
Pingré, “the order sent, they became visible and commenced their
journey. If, whilst on their way they put forth a tail, the star was
said to have become a comet.”
The above quotation, remarks the same author, explains:
“the foolish and singular idea that the Chinese formed of the
heavens. According to them, the heavens represented a great empire,
composed of kingdoms and provinces; these provinces were the
constellations; there was decided all that would happen for good or
ill to the great terrestrial empire, that is, to China. The planets
were the administrators or superintendents of the celestial
republic, the stars were their ministers, and the comets their
couriers or messengers. The planets sent their messengers from time
to time to visit the provinces for the purpose of restoring or
maintaining order, but all that was done in the heavens above was
either the cause or the forerunner of what was to happen below.”
The ideas of the Chinese were not more foolish than the extravagant
myths of the ancients, and of the Europeans in the Middle Ages.
Nevertheless, although comets are no longer regarded with superstitious
awe, mystery still clings to them. For those who are unaware of the fact
that astronomers can trace their paths, predict the periodic returns of
these wanderers, and even analyze the substance of which they are
composed, there are many problems concerning them still awaiting
solution.
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.”
CHAPTER THREE
THE STORY OF DONATI’S COMET
Hast thou ne’er seen the comet’s flaming flight?
Th’ illustrious stranger, passing terror sheds
On gazing Nations, from his fiery train
Of length enormous, takes his ample round
Thro’ depths of ether; coasts unnumbered Worlds,
Of more than solar glory, doubles wide
Heaven’s mighty cape; and then revisits Earth,
From the long travel of a thousand years.
—YOUNG. “Night Thoughts.”
When a comet draws near to pay its respects to its ruler, the sun, it
usually assumes a splendor befitting this momentous occasion. It adorns
itself with a glittering train millions of miles in length, and composed
of myriads of particles reflecting the sun’s light. The head is often
enveloped in a multiplicity of transparent veils, through which bright
jets may be seen emanating from the star-like nucleus within. Some
comets have been seen with five or six trains, spread out like that of a
peacock, the camera revealing rapid and marvelous changes in their
appearance, during the course of a few hours. No fair débutante, about
to be presented to royalty, could vie with a comet in capriciousness
regarding her raiment, nor could she equal it in splendor, even though
she owned the mystic lamp of Aladdin.
The brief assumption of splendor on the part of a comet is very unlike
its usual humdrum existence when it is as yet so far distant as to be
not only invisible to the comet-hunter, but beyond range of the
far-reaching eye of the telescope or the entrapping power of the camera.
Not the slightest impression is made on the photographic plate, and as
far as an observer on planet earth is concerned the comet might have
ceased to exist. It is only when it begins to draw near to the sun that
we are enabled to obtain a record of the marvelous changes produced in
its appearance, until at its nearest approach it has sometimes been
known to vibrate as though with intense excitement. For instance, in the
case of Biela’s comet, concerning which a special account is given
further on, it was apparently so overcome at its last appearance in
1846, that it split in two and literally went to pieces.
Quite a different story is told concerning the magnificent comet which
greeted us in the summer of 1858, and was first seen at Florence on the
2d of June by Giambattista Donati, after whom it was named. At the time
it was merely a nebulous mass about one-twentieth the diameter of the
moon, and for some weeks it retained about the same brightness except
for a gradual increase in the central star-like point, the only
indication of its coming splendor. At the end of August it had increased
so rapidly in brightness that by September it was visible to the unaided
eye, resembling a hazy-looking star adorned with a small tail.
Gradually, as it drew nearer to the sun, it increased in size and
splendor, reaching its maximum brightness in October. Its train extended
over an arc of forty degrees, or eight times the distance separating
Alpha and Beta—the so-called pointers in the constellation of Ursa
Major, the Great Bear. Its real length was then about forty-five million
miles, with a width of ten million. The nucleus varied in diameter from
five hundred miles to three thousand, or nearly half that of our planet
earth.
The comet was kept under accurate observation for fully nine months, and
during part of that time it was visible to the naked eye. Professor G.
P. Bond, the director of the Harvard College Observatory, availed
himself of the opportunity thus presented, of making a series of
drawings of the comet which convey an excellent idea of its changing
appearance, and the delicate shadings and misty outlines of this
marvelous visitant from the star-depths. These drawings are of all the
more value, since it will be nearly two thousand years before Donati’s
comet visits these realms again.
To go back to the earlier history of the comet, before these drawings
were made, we find that its tail was not observed telescopically until
seventy-three days after Donati’s discovery. It was seen on August 14,
1858, by astronomers at Copenhagen and Vienna, but not at Harvard until
the 20th of that month. The brilliancy of the comet was somewhat
impaired by a strong twilight and its low altitude. This may account for
the fact that it was described as ruddy in hue, and concentrated, and
having a mere suggestion of a tail. On August 23 the tail was still so
faint as to be easily overlooked in the moonlight, the record being:
“Bright, but no trace of a tail; the sky clear, but the moon nearly at
full.” On August 30, according to the record in the _Times_ (London), of
observations made by J. Russell Hind, “The comet was just perceptible to
the naked eye; its nucleus is strongly condensed and brilliant, and the
tail is thrown off in the ordinary form, without bifurcation.”
During the month of September the tail of the comet showed a tendency to
curve, and by September 7 it was recorded as being very conspicuous to
the naked eye. September 12 it had increased wonderfully in brilliancy,
and on September 16 the first sketch was made by G. P. Bond, showing a
view of it with the naked eye. The tail was now estimated as being 7°
long, thus exceeding the distance (of 5°) separating the pointers. A
tangent to the convex edge near the nucleus prolonged would pass through
Delta in Ursa Major, and it was noticeable that this side was the
brightest in all the sketches. A narrow dark channel extending from the
nucleus up the axis of the tail was very remarkable, and its edges were
surprisingly well defined, especially very near the nucleus. In fact,
the comparatively sharp definition of the eastern edge of the tail was
in marked contrast to the softness of outline on the western side. (See
_Monthly Notices_, R. A. S., Vol. XIX, pp. 88–89.)
By September 27 the length of the tail as observed with the naked eye
was about 9° or 10°. It was curved, convex toward the star Cor Caroli,
being much better defined on the side near the star than on the concave
side. The narrow dark stripe in the axis of the tail was still very
marked, and the outline of the tail could be traced from the nucleus
halfway to Delta in Ursa Major, and a degree or so further. It was now
strongly curved and its upper outline well defined and bright as
compared with the inner. A straight ray or secondary tail could be seen
faintly suggested on the eastern side and reaching northward from the
main tail.
By October 3 a marvelous change had taken place in the appearance of the
comet. The train had increased in length and brightness, extending
nearly as far as Eta in Ursa Major, and the straight ray or secondary
train was still very much in evidence. It was supplemented by another
slender ray, as shown in drawings made by Professor Bond on October 4
and 5, but it had vanished by October 6, although its position was
indicated, for that date, in the faint suggestion of a ray between the
main tail and the outer or secondary tail. The bright star to the left
of the nucleus of the comet is Arcturus (in the constellation Boötes),
over which the comet passed without perceptibly diminishing its
brightness, thus showing of what airy texture the train of a comet is
composed. Was it not Sir John Herschel who said that a comet could be
easily packed in a portmanteau, and in the recent edition of _The Vault
of Heaven_ Sir Richard Gregory gives the following unique illustration
of the insignificance of the whole mass of a comet:
[Illustration: