UNIVERSITY OBSERVATORY PREPARES TO PHOTOGRAPH CORONA OF SUN'S ECLIPSE

"Yes, we expect to begin the time trials in a day or two," said assistant Professor Edward S. King, when interviewed by a CRIMSON reporter recently at the University Observatory. Professor King was not talking about a track meet, but about the preparations which are being made by the University to observe the total eclipse of the sun which takes place on January 26th.

"Time," he continued, "counts for everything in observing eclipse. Two or three weeks before its occurrence we have to go through all the motions of taking the photographs. Sometimes the slide will stick, or the camera may not be in working order. Nothing like this can be allowed to happen on the day of the eclipse. We must be absolutely sure that everything is in perfect order, and we must practice for speed. In the past, I have often had the stop watch on me, as I practiced changing the slides. A few seconds makes all the difference in the world."

Professor King went on to describe the corona, the particular phenomenon of the eclipse which the University Observatory is concentrating on.

Have Four Photometer Cameras

"When the moon completely covers the sun, at the height of the eclipse" he said, "there will still be rays shooting out around the edges of the moon, which are called the corona. The corona has approximately the same total light as that of the full moon. It is made up probably of great tongues of flame which shoot thousands of miles out into space, and are reflected by something in the air, the nature of which has not yet been determined.

"Our problem is to study the total brightness of the corona. For this purpose we have four photometer, cameras, consisting of a box with a plate at one end and a pinhole at the other.

"Since the eclipse will not be total in Cambridge," he continued, "we are cooperating with the Maria Mitchell Observatory on Nantucket Island, which lies in the path of the total eclipse. Two of us expect to go there, while Professor Shapley will travel to an observatory in the western part of the state or in eastern New York."

Amateurs Should Use Negatives

When Professor King was asked what the amateur could do in the way of observation, he said, "I should suggest either a smoked glass or a blackened negative. Perhaps the latter would be preferable," he added, smiling slightly, "as it won't smudge your face as you gaze heavenward.

"The diameter of the sun will be 99 per cent covered in Cambridge," he continued, "so that you will get a rather good chance to observe all the phenomena of the total eclipse. It will begin at four minutes past 8 o'clock on the morning of January 24, and will be at its height at 15 minutes past 9 o'clock. One thing of great interest is to observe the peculiar images cast by the sun during the partial period. A ray of light through a knot hole, for instance, will cast a crescent shaped image on the floor instead of the ordinary round one.

Must Have Clear Day

"What every body is praying for now," continued Professor King, "is a clear day. A cloudy sky would spoil everything, though we would probably go through the motions of taking the pictures under any circumstances."

In this connection it is interesting to note that most observatories, according to Professor Shapley, have insured themselves against total loss, if the weather is bad, so the insurance companies also are hoping for a clear day on January 24.

The last total eclipse occurred in Massachusetts over 100 years ago. In 1806 Nathaniel Bowditch, a prominent Massachusetts citizen of that day, observed a total eclipse from Salem, and remarked especially on the corona, though he did not call it by that name.