Stardust Memories: Frank E. Seagrave and Halley's Comet

March 2003  :  Dave Huestis

During the fall of 1909 "prophets" and doomsayers were predicting dire earthly calamities because of a forthcoming celestial event -- the return of Halley's Comet from the outer reaches of our solar system. However, in Providence, Rhode Island, an almost half-century year old "amateur" astronomer was already basking in the cometary light of stardom.

While many of the general public feared the comet would hit the earth, others thought the cyanogen gas discovered in the comet's tail would extinguish all life on our planet. Meanwhile, Frank Evans Seagrave kept his eye glued to the eyepiece of his 8 1/4 inch Alvan Clark refractor, carefully studying this celestial snowball whose orbit it had taken him 3 years to compute.

Worldwide acclaim was his. But who is this man and what events led him to the forefront in astronomy? And why are there no references throughout the literature on Halley's Comet that mention the man or his magnificent work? His tale is a fascinating one.

Frank Evans Seagrave was born March 29, 1860, son of Mary Greene (Evans) and George Augustus Seagrave. George was a wealthy textile mill owner just outside of Providence, as well as a Providence bank president. Young Frank went to a private school, and it was there that he acquired a knack for mathematics. On October 26, 1874, at the age of 14, his interest in astronomy was awakened by an eclipse of the moon. So great was this new interest that his father bought him a 3- inch refractor soon after. It is reported that Frank observed every fair night.

In 1875 he began travelling to the Harvard College Observatory (HCO) twice a week, where, even though he wasn't enrolled as a student, he was given access to the library and instruments. Frank's father was so impressed with his son's new-found activities that he purchased an 8 1/4 inch Alvan Clark refractor as a present for Frank's 16th birthday. He continued to observe with this great instrument which was then the 3rd largest in New England, and was the largest in New England in private hands.

Then in 1878 he erected an observatory in the backyard of his father's house at 119 Benefit St. in Providence, RI (probably because he got tired of lugging this large 6 foot telescope, mount, and heavy accessories outside each time he wanted to observe, and having to polar align it again and again). The telescope was mounted in May. Present at the dedication ceremony was none other than Alvan G. Clark, the famous telescope maker. Also present was Leonard Waldo, Assistant Director of HCO under E.C. Pickering, who thought the "complement of accessories attending the telescope could occupy the time of two competent observers."

Also at this time young Seagrave was invited to participate in a government sponsored solar eclipse expedition to Ft. Worth, Texas, his first of many to come. During the ensuing years Frank Seagrave observed a myriad of objects, including the sun, variable stars, comets, novae, asteroids, and of course the planets. Then again in 1877, another government sponsored solar eclipse expedition took him to Pottsdam, Germany, where Frank not only observed and photographed the reversing layer, but also obtained prominence and corona spectra. The year 1900 provided a similar opportunity in North Carolina.

Of particular note concerning the planets, in 1901 and 1902 Frank made micrometer measurements of the planet Saturn and it's ring system. It seems the German astronomer von Struuve had made similar studies and had determined that the distance between the planet's disc and the rings was decreasing very rapidly. In fact, von Struuve predicted that the rings would crash down on the planet's "surface" by the year 2150. Mr. Seagrave noted no decrease. Latter in 1914 and 1915 Seagrave made the same measurements. No change was detected.

Also of importance, Frank observed and photographed the transit of Venus in 1882 from his observatory in Providence. But the great event that would bring Frank E. Seagrave to the forefront of the astronomical world was slowly making its way through the outer reaches of the solar system. In 1906 while Frank was reading a German magazine, he came upon an old observation of Halley's Comet. He decided at once to work out an ephemeris for the comet so that he would know where in the sky it might be. Mr. Seagrave worked on the calculations for three years and finally sent the ephemerides for the orbit to E.C. Pickering, Director of HCO).

Many letters passed between Seagrave and Pickering at this time. A prophetic one was dated August 4, 1909, in which Frank wrote, "I should say it would be all right to begin a systematic search for the Comet photographically about the end of this month. I should say it would be visible nicely with your 15 inch telescope by the middle of October next. I hope that Max Wolff will not get the better of us on this. We want the American astronomers to see it first."

Wolff did recover the comet on a photographic plate taken on September 11, 1909, the first time plates had been used for such a search. Regardless, Frank Seagrave's calculations proved to be quite exact. At recovery the comet was very near where Seagrave had computed it to be at that time. In fact with further observations from Yerkes Observatory, it was determined Frank was only off by 54 secs. in R.A. and 14 mins. 32 secs in declination.

Congratulatory telegrams and letters came from all over the world from the most prestigious astronomers of the time. Crommelin, of the Royal Greenwich Observatory, England, who had previously calculated Halley's to the greatest degree of accuracy at the time (still 3 days in error), rightly praised the accuracy of Seagrave's ephemerides. The French astronomer Flammarion was so impressed with Seagrave's orbital elements that he publicly acclaimed them and used them for his own studies of the comet.

However, when Frank learned that his computations had some error, he began to re-calculate the ephemeris based on current observations. It was then that he made a startling discovery. On May 18, 1910, the earth would not only pass through the tail of Halley's Comet, but the comet would also be seen to transit the sun. Unfortunately the transit would not be visible form the continental United States (sun below our horizon at that instant).

"But," said Mr. Seagrave last night (November 27, 1909) as he prepared to follow the course of the total lunar eclipse at his private observatory, 119 Benefit Street, "we will have our spectacle here. Even if we cannot witness the transit, the tail of the comet, streaming out toward us, will afford us here a spectacle to be remembered. The comet's tail will sweep as a gigantic streamer across the night sky and will appear as a magnificent aurora. If the tail is 10,000 miles broad it will sweep practically over half of the sky. This interesting phenomenon will be brought about through the fact that the comet will be right on the earth's plane at that date, and the tail, repelled from the sun, will stream in toward us and will be readily observed in the night sky."

During the lunar eclipse Frank paid more attention to the comet, which only a few degrees away had been obscured by overwhelming moonlight. He noted that it appeared much brighter than when he had observed it more than a week earlier. Based on these observations he predicted that the comet would become a naked eye object by New Year's Day, and by late March or mid-April, much detail would be observable.

Frank continued to observe the comet as it began it's headlong approach to the sun. Not only was he interested in watching the development of the comet, but more importantly he was monitoring the comet's orbit to detect any variance from his calculations. By December Frank reported seeing a "wisp of a tail ... It is not a well-defined tail as yet, but more of an elongation of the cometary head, making the comet appear somewhat oval ...". Though Halley's would be a telescopic object during January 1910, and a difficult naked-eye object by the end of February, not until April and May would it put on a spectacular show.

But on January 19, 1910, a new visitor to the inner solar system became visible in the western sky for 15 minutes after sunset. This very brilliant, fast moving comet, with a very conspicuous tail was seen while the sun was setting. The head hung like a red ball in the blue sky, while the tail stretched for several degrees behind it. It was believed to be the brightest comet since the Comet of 1882.

On the 20th, Frank received a telegram from Lick Observatory stating that the comet was "plainly visible to the naked-eye at noon-day". On the 22nd the comet, now known as 1910A, outshone brilliant Venus. By the evening of the 23rd the bright head and long filmy tail was watched by thousands of Rhode Islanders. Many thought Halley's Comet had put in an early appearance. Frank laid that idea to rest promptly: his calculations showed Halley to be right where it should be. He further stated that Halley would be even better. The press got that idea across as well because not very much newsprint was devoted to 1910A. They, especially the astronomers, should have known better. (We'll come to that shortly.)

Frank's ephemeris of 1910A showed the orbit to be a parabola, in which only a slight change could cause it to be an ellipse. His calculations supported the idea that 1910A was making its first encounter with the sun, hence its brilliancy. The comet's orbit dictated that it would never return to the inner solar system. Interest in Comet 1910A passed almost as quickly as the comet did. Now all everyone had to do was wait for the Great Halley's Comet. However, the only thing predictable about Halley was its orbit.

Just seven days before perihelion, on March 27, observers at HCO saw a 1 degree tail. After perihelion though, no tail was observed or photographed on the 11th, 14th and 25th from observatories around the world. This development, or lack of it, should not have been too surprising. Halley's in 1759 had a faint, disappointing tail. The 1835-36 apparition showed a pre-perihelion tail of 24 degrees, but postperihelion showed an expanded head with no tail. Unfortunately the 1910 apparition was going to be an event entirely unique.

Beginning in May many newspaper articles began to appear concerning people's fear of the comet. Ninety-four year old Mr. Wilbur of Providence who remembered the fear Halley caused in 1835 said of the current apparition,"... for astronomy has made great strides since those days and people are not superstitious." Was he wrong!! People didn't want to know what would happen. They began querying "what if" scenarios -- what if conditions were different, what could happen? Some writers, astronomers among them, fed the public stories on the consequences of Halley's comet colliding with the earth. Others wrote of the comet as a "seething mass of flames". And of course the astrologers had a field day.

It was the announcement of the discovery of cyanogen gas in Halley's tail that got everybody frightened. With this news came reports of what cyanogen gas was and what effects it could have on the human population. It became blown way out of proportion. The gas detected was so tenuous that Professor Mitchell of Columbia University stated, "I believe that if a cubic mile of the comet's tail could be gathered and put into a beaker, it would require the most minute chemical tests to detect anything more than a trace of the poisonous gas." But the damage had already been done. Some people were panicking.

As the comet neared the earth, Frank Seagrave was frequently called upon by the local press for observing reports and comments on the actions of the comet. One such observation on the 13th of May showed a distinct area of the comet showing "jets of light bursting ... piercing the haze enveloping the glowing arc of the nucleus." He also reiterated the sun transit circumstances saying, "There may be a slight diminuation of the sun's rays, but it will probably be simply as a light wisp or fog passing over the sun ... The tail at the time of conjunction may be visible here on the midnight sky."

But the tail was not behaving properly. A report from Lowell Observatory to Frank Seagrave stated that a photograph of the comet on May 1st showed "the action of some disintegrating force, some shattering and sudden force ... (possibly) the comet's nearest approach to Venus ...". And as observed by Frank, "the flaring out in the tail, a divergence of the outer streamers and a narrowing down again as if they actually approached and receded from each other."

On May 15th, the Providence Journal began promoting "Comet Week: Arrival of the Best Advertised Heavenly Wanderer". The 1985-86 apparition, as unfavorable as it may be, will render that apt title to the scrap heap. "This performance", wrote the Sunday Journal, "will duly instill the comet as an evening attraction and for the next few nights star gazing will be the established occupation of the public."

However, fear was still a big problem. Mr. Seagrave had many queries on the comet's possible destruction of the earth by collision. In fact, one prominent businessman from Providence refused an invitation to spend Wednesday night (May 18th, when comet's tail would sweep over the earth) at Frank's observatory, insisting that the place for a conscientious man was at home with his family.

Frank made every effort to comfort the public commenting, "There seems to me to be absolutely no reason for fear of the comet. The comet is twice as far away now as it was in 1066 and no harm was done to the earth then. It will be just about as close to us Wednesday night as it was to Venus two weeks ago. I turned my telescope on Venus last night and she was still there. I couldn't notice that she had suffered any harm." According to some of the press reports though, many people continued to believe that the end of the world was at hand. Some people, too nervous to sleep, remained awake all night in case something unusual happened.

Regardless, Frank anxiously waited for the comet's tail, then 20,000,000 miles long and 1,000,000 miles wide, to intercept the earth at 10:50 P.M. He was cautious in predicting what could be seen saying, "I do not see how anything more spectacular can occur than the appearance of bands of light across the skies. It would be fine if we could have showers of meteors such as have occurred at various times in history, but I think that we can expect nothing of the sort. If we were going to pass through the comet's tail at a point several miles nearer the head than we are we might have some beautiful shooting stars, but the gases of the tail are so thin and unsubstantial that such phenomena are not to be expected. But you can't tell just what will happen: nobody knows. Everything anyone says is the merest guesswork."

In the early evening of May 18th, in Providence, after the passing of very black storm clouds, "one of the most gorgeous sunsets ever seen here" cast an eerie "orange golden glow" across the city. Of course many people attributed this atmospheric effect to the comet. Said Mr. Seagrave, "It would not be reasonable to suppose that something which was coming on us several million miles away of such rarity as the comet's tail is believed to be, could affect the weather conditions here in the least."

Later in the evening throughout the city, people were outside waiting for something to happen at the appointed hour of the earth's passage through Halley's tail. Providence at the time was wrapped in a hazy fog, again attributed to the comet by some, while others "in the vicinity of the Great Bridge, catching a whiff of the familiar 'Providence smell', were certain that they were able to trace the cyanogen gas of the comet's tail." "What I would like to see", Frank said, "would be an exhibition which would appear as the most vivid and beautiful aurora ever witnessed." Nothing was visible due to the fog, though nothing happened anyway. Even Hawaiian astronomers, who had hoped to observe the solid nucleus of Halley's transiting the sun (an event calculated by Seagrave), were very disappointed. No presence of the comet could be detected.

Then the unusual began to occur, not threatening to the earth, but it did greatly affect the comet. Large eruptions were observed on the sun on May 18th. "The sun spots and the comet had nothing in common with one another", said Frank Seagrave, but they were unusual at that time in the solar cycle. On the night of the 19th Halley's tail should have been observed, but the only thing visible was an aurora caused by the unusual solar activity. Of course everyone at first mistook the aurora for Halley's tail.

Meanwhile, Frank scanned for the tail, but could find none. "It's almost incredible, but everything indicates that at almost the very moment when we should have been entering the comet, the tail gave a sudden turn backward, which threw it out of our path sufficiently to allow us to get by without going through the comet's substance. The calculations of all the astronomers had been based on the belief that the tail would remain straight. If it had we would have had the experience of travelling through a million miles of comet tail. But it bent backward and got by us. It is out of the question now for us to expect to run into the comet on its present visit. All chance of passing through the tail is now gone, because of the difference in the angle of the two orbits. I must admit that I am surprised. Every other calculation I have made has been proven exactly correct. The head has met every expectation and has followed exactly the course I mapped out months ago. It crossed the disc of the sun exactly on time and is now on its journey to aphelion, but the tail has played us a funny trick. Frankly, I don't know just when we shall see the tail. I wouldn't be surprised to see it bobbing up above the horizon any minute, but I won't promise now that it will be seen before Saturday night. I think that by that time it ought to be bent back into shape so that it will flash its light above the horizon. The comet's head will probably be seen for a little while to-night in the northwestern sky, but Saturday night and early next week the head will be higher and the view will be much finer."

Also on the 19th, Yerkes Observatory astronomers observed a broad spectrum of light across the sun that was attributed to Halley's tail. During mid-day on the 20th, Frank Seagrave attempted to find the comet, but without any luck. Then when Halley moved into the early evening sky (7:40 P.M.) that same day, no tail was observed at all by Yerkes. Frank tried in vain to observe the comet but a thick band of clouds obstructed the western sky. Later that evening the aurora reappeared and even a halo surrounded the moon. Frank Seagrave had to deny that either of the two events had anything to do with Halley's Comet.

Frank also reported that based on the spectrum obtained by Yerkes, and on the observation of a beam of light seen by astronomers in the eastern sky on Thursday morning (believed to be a branch of the comet's tail), the earth passed through the leading branch of the tail and was then in the area between the two branches. The earth's passage through the tail therefore occurred sometime between 8 - 12 A.M. Thursday morning.

Poor weather continued to plague Frank. Thick clouds again covered the sky on the 21st. Reports from elsewhere under better conditions reported a "fan-tailed pigeon's appendage" in describing Halley's tail. So Frank decided to go to Harvard. Reports stating Halley to be brighter than Venus and with a 40 degree tail excited Frank tremendously. He was also hoping for better observing prospects. It was at this time that two theories emerged concerning the unusual circumstances of the tail. Some astronomers believed the pre-perihelion tail may have been stripped off by the unusual solar activity. Others believed Halley's tail split in two leaving the earth between the two branches.

Providence and the entire eastern seaboard remained under a shroud of clouds. Then on the night of the 22nd at 8:35 P.M., Frank Seagrave got his first post-perihelion glimpse of Halley's Comet. All he saw was the comet's head, measurements of which he took to confirm the orbital elements he had previously derived. On the 24th Harvard photographed Halley, then at magnitude +2.0 with a 10 degree tail. Unfortunately the comet was rapidly receding from the earth and growing dimmer all the while. Back in Providence, Halley's Comet observers were "getting reconciled to their fate, and confidently voice the opinion that they will have to live another 76 years and then move elsewhere if they expect to see the comet."

Then finally on May 26th, a full week after perihelion, Frank Seagrave and Providence saw the comet in the western sky. It had a 30 degree tail that stretched to the south and it shone brightly against a black sky. To the unaided eye the comet's head looked like a large dim and hazy star, while the narrow tail splashed up into the dusky sky. Seagrave was pleased to verify his computations of Halley's orbit by setting his telescope on the sky by merely using his calculations and his setting circles.

Just before 8:00 P.M. he caught the faint glimmer of the comet .... in the center of the field!!! "I can go down the street again now and look my fellow men in the eye. It is simply impossible for anyone to realize the mental strain I have been under as the result of this bad weather." He was being ridiculed and accused for the comet not being visible, much like we blame weather-persons today for forecasting bad weather. But there it was. Nothing had happened to the earth or its inhabitants.

Frank then took on the air of a philosopher, "There is something pathetic to me in the departure of the comet. To-day the whole world is worked up over the comet's visit. But soon it will fade so that the naked eye cannot perceive it. We astronomers will keep it in sight, though, until almost New Year's. But when it fades out entirely - and this is what seems so pathetic - it will not be seen again by the eye of man until nearly every human being now living is dead. There will be a few children who will live to see it again, but in 1986, when it makes its next appearance, it will be as new to the generation then living as it has been to the people to-day."

By now the tail was so faint that even the slightest cloud wisps would overwhelm it. To the naked eye it seemed to be no more than a "luminous haze". Harvard also got its first look at Halley's on the 26th, noting a 40 degree tail. According to a Harvard astronomer, "... it was recently reported that the nucleus had divided, nothing of such a division was seen: in fact, the head of the comet was found to be quite sharp and stella. The maximum of light or 'jet', which was seen projecting from the nucleus toward the southwest on May 2 and May 24, measuring some 2 and one-half minutes of arc, had entirely disappeared to-night."

On the 27th only the head and nucleus were observable in Providence due to haze. Though visible for 1 1/2 hours, nothing of consequence was observed by Frank Seagrave. Interest was diminishing as rapidly as the comet, since it soon became only a telescopic object. These observations were continued by Mr. Seagrave, but nothing spectacular was reported. The hoopla over Halley's was over, so Frank returned to his regular routine. However his story doesn't end here with Halley's departure. But that's a story for another time.

The comet continued its outbound journey into history and aphelion, and was soon forgotten by the general public. But interest is again on the increase, many only interested in making a few bucks on the return of the celestial snowball. But for amateur astronomers it will truly be an experience of a lifetime. And while my wife Tina and I observe this heavenly wanderer from the island of Bonaire, Frank Seagrave will be right there with us, checking up on Halley's orbital elements.

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From The Historian

Frank Evans Seagrave (1860-1934)