Nan Dieter Conklin: A Life in Science
by N.D. Conklin, © 2001
Modified on Monday, 29-Dec-2003 17:14:21 EST by Ellen Bouton
Nantucket: Variable Stars
Helen protested, "You canít know that you want to make astronomy your career without some experience of the real thing," and she set about finding me the chance to get it. For the summers of 1947 and 1948 I got fellowships to the Maria Mitchell Observatory on the beautiful island of Nantucket. I discovered many things there, not all of them astronomical. I was terrified of Margaret Harwood, the director and sole permanent member of the tiny observatory. (It was my first time away from home.) Miss Harwood knew the right way to do things, and I clearly did not.
Our principal work lay in the study of stars that vary in brightness. Since the telescope was a small 7.5" refractor, hour-long exposures were required to reach the faint stars we were after. That, of course, ruled out study of the very interesting short-period variables. Lesson #1 in fitting the study to the equipment. The photographs were made on 8x10 glass plates that I handled very carefully (Occasionally we washed the stored plates to remove salt spray that actually reached our closed, polished wooden cabinets. Those were tense days.) After choosing several variable stars of interest, we used the coordinates of a reasonably bright star near the center of the field to set up the telescope and begin the exposure. The guidance mechanism of the 7.5" was very good but not accurate enough to produce perfect round stellar images over such a long exposure. The only way to get them was to keep the central star precisely on cross-hairs in the eyepiece by moving the telescope a little, very little, with a hand-held manual control. The quality and vigilance of the observerís control were apparent in the shape of the final images.
The demands of becoming an extension of the telescopeís guidance system did not prevent my being aware of the pure beauty of the night sky. Nantucket is thirty miles at sea, and a clear night there has a quality that is both indescribable and unforgettable. I became aware for the first time of the sweep of the stars across the sky from dusk to dawn. I was amazed at how often I had to move the slit of the telescopeís dome to keep up. Hard to believe that the majesty of the motion results from a simple thing like the rotation of the earth.
After a plate was developed the next step was to identify an image of a star varying in brightness with time. It was often a known variable but one for which neither the amplitude nor period of the variation had been determined. The brightness of the star on our new plate was compared with that on earlier ones - hence the need for those perfect round images. The process was a good deal more tedious than it sounds, but it was a thrill (albeit a small one) to find the time interval that was the period of a regularly varying star. It after all was new. This was Helenís "real thing", and it was all I had hoped it would be.