The Reminiscences of an Astronomer

by Simon Newcomb

When the telescope was approaching completion I wrote to the head of one of the greatest European observatories, possessing one of the best telescopes of the time, that the first thing I should attempt with the telescope would be the discovery of the companion of Procyon. This first magnitude star, which may be well seen in the winter evenings above Orion, had been found to move in an exceedingly small orbit, one too small to be detected except through the most refined observations of modern precision. The same thing had been found in the case of Sirius, and had been traced to the action of a minute companion revolving around it, which was discovered by the Clarks a dozen years before. There could be no doubt that the motion of Procyon was due to the same cause, but no one had ever seen the planet that produced it, though its direction from the star at any time could be estimated.

Now, it happened that my European friend, as was very natural, had frequently looked for this object without seeing it. Whether my letter set him to looking again, or whether he did not receive it until a later day, I do not know. What is certain is that, in the course of the summer, he published the discovery of the long-looked-for companion, supplemented by an excellent series of observations upon it, made in March and April.

Of course I was a little disappointed that the honor of first finding this object did not belong to our own telescope. Still I was naturally very curious to see it. So, on the very first night on which the telescope could be used, I sat up until midnight to take a look at Procyon, not doubting that, with the greater power of our telescope, it would be seen at the first glance. To my great concern, nothing of the sort was visible. But the night was far from good, the air being somewhat thick with moisture, which gave objects seen through it a blurred appearance; so I had to await a better night and more favorable conditions. Better nights came and passed, and still not a trace of the object could be seen. Supposing that the light of the bright star might be too dazzling, I cut it off with a piece of green glass in the focus. Still no companion showed itself. Could it be that our instrument, in a more favorable location, would fail to show what had been seen with one so much smaller? This question I could not answer, but wrote to my European friend of my unavailing attempts.

He replied expressing his perplexity and surprise at the occurrence, which was all the greater that the object had again been seen and measured in April, 1874. A fine-looking series of observations was published, similar to those of the preceding year. What made the matter all the more certain was that there was a change in the direction of the object which corresponded very closely to the motion as it had been predicted by Auwers. The latter published a revision of his work, based on the new observations.

A year later, the parties that had been observing the transit of Venus returned home. The head of one of them, Professor C. H. F. Peters of Clinton, stopped a day or two at Washington. It happened that a letter from my European friend arrived at the same time. I found that Peters was somewhat skeptical as to the reality of the object. Sitting before the fire in my room at the observatory, I read to him and some others extracts from the letter, which cited much new evidence to show the reality of the discovery. Not only had several of his own observers seen the object, but it had been seen and measured on several different nights by a certain Professor Blank, with a telescope only ten or twelve inches aperture.

"What," said Peters, "has Blank seen it?"

"Yes, so the letter says."

"Then it is n't there!"

And it really was not there. The maker of the discovery took it all back, and explained how he had been deceived. He found that the telescope through which the observations were made seemed to show a little companion of the same sort alongside of every very bright star. Everything was explained by this discovery. Even the seeming motion of the imaginary star during the twelve months was accounted for by the fact that in 1873 Procyon was much nearer the horizon when the observations were made than it was the year following. [1]

There is a sequel to the history, which may cause its revision by some astronomer not many years hence. When the great telescope was mounted at the Lick Observatory, it is understood that Burnham and Barnard, whose eyes are of the keenest, looked in vain for the companion of Procyon. Yet, in 1895, it was found with the same instrument by Schaeberle, and has since been observed with the great Yerkes telescope, as well as by the observers at Mount Hamilton, so that the reality of the discovery is beyond a doubt. The explanation of the failure of Burnham and Barnard to see it is very simple: the object moves in an eccentric orbit, so that it is nearer the planet at some points of its orbit than at others. It was therefore lost in the rays of the bright star during the years 1887-94. Is it possible that it could have been far enough away to be visible in 1873-74? I need scarcely add that this question must be answered in the negative, yet it may be worthy of consideration, when the exact orbit of the body is worked out twenty or thirty years hence.