"Fred Hoyle - The Black Cloud" - читать интересную книгу автора (Hoyle Fred)

first at one plate, then at the other, then back to the first one again, and so on in
fairly rapid succession. When this was done, any star that had changed
appreciably during the time interval between the taking of the two plates stood
out as an oscillating or 'blinking' point of light, while on the other hand the vast
majority of stars that had not changed remained quite steady. In this way it was
possible to pick out with comparative ease the one star in ten thousand or so that
had changed. Enormous labour was therefore saved because every single star did
not have to be examined separately.
Great care was needed in preparing plates for use in the 'blinker'. They must
not only be taken with the same instrument, but so far as possible must be shot
under identical conditions. They must have the same exposure times and their
development must be as similar as the observing astronomer can contrive. This
explains why Jensen had been so careful about his exposures and development.
His difficulty now was that exploding stars are not the only sort to show
changes. Although the great majority of stars do not change, there are a number
of brands of oscillating stars, all of which 'blink' in the manner just described.
Such ordinary oscillators had to be checked separately and eliminated from the
search. Jensen had estimated that he would probably have to check and
eliminate the best part of ten thousand ordinary oscillators before he found one
supernova. Mostly he would reject a 'blinker' after a short examination, but
sometimes there were doubtful cases. Then he would have to resort to a star
catalogue, and this meant measuring up the exact position of the star in
question. So all in all there was quite a bit of work to do before he got through
his pile of plates - work that was not a little tedious.
By 14th January he had nearly finished the whole pile. In the evening he
decided to go back to the Observatory. The afternoon he had spent at the
California Institute of Technology, where there had been an interesting seminar
on the subject of the spiral arms of the galaxies. There had been quite a
discussion after the seminar. Indeed he and his friends had argued throughout
dinner about it and during the drive back to the Observatory. He reckoned he
would just about get through the last batch of plates, the ones he had taken on
the night of 7th January.
He finished the first of the batch. It turned out a finicking job. Once again,
every one of the 'possibilities' resolved into an ordinary, known oscillator. He
would be glad when the job was done. Better to be on the mountain at the end of
a telescope than straining his eyes with this damned instrument, he thought, as
he bent down to the eye-piece. He pressed the switch and the second pair
flashed up in the field of view. An instant later Jensen was fumbling at the plates,
pulling them out of their holders. He took them over to the light, examined them
for a long time, then replaced them in the blinker, and switched on again. In a
rich star field was a large, almost exactly circular, dark patch. But it was the ring
of stars surrounding the patch that he found so astonishing. There they were,
oscillating, blinking, all of them. Why? He could think of no satisfactory answer to
the question, for he had never seen or heard of anything like this before.
Jensen found himself unable to continue with the job. He was too excited
about this singular discovery. He felt he simply must talk to someone about it.
The obvious man of course was Dr. Marlowe, one of the senior staff members.
Most astronomers specialise on one or other of the many facets of their subject.
Marlowe had his specialties too, but he was above all a man of immense general
knowledge. Perhaps because of this he made fewer mistakes than most people.