Abstract
IN his twenty-third annual report to the Solar Physics Committee the Director of the Solar Physics Observatory, Cambridge, is able to point to a number of interesting results obtained from a particularly active year. To begin with, the 3-ft. Common mirror has been refigured by Dr. Burch, who has developed a special new method of testing paraboloids in this connexion. The performance of the mirror is greatly improved, and it is hoped to improve the 10-in. secondary mirror used with this large mirror and so obtain really good definition with the 3-ft. telescope. The year's work on stellar spectro-scopy has been notable on account of special observations made during the eclipse of Aurigae and for the work on Nova Herculis. A very special effort was made, and altogether 284 spectra were secured on 137 nights between December 13, 1934, and July 31, 1935. This is a very fine performance for the climate of Great Britain, and was only made possible by enthusiastic team work by the staff and research workers at the Observatory. An item of interest is the attempt made by Drs. Redman and Bullard to determine the diameter of Antares by observing the brightness during an occultation by the moon. Unfortunately, the apparatus broke down at a critical point in the observation, but there appears to be nothing unworkable in the method, which is of extreme interest, and it is to be hoped that the experiment will be repeated at the next favourable occultation. The solar work has continued, perhaps the most noteworthy item being the accurate determination of the central intensity of the line at 4227 A. (due to Ca+) by Dr. Redman, the result being 2 per centpossibly the lowest central intensity yet accurately measured. The Observatory has arranged to send an expedition to observe the total solar eclipse of June 19, 1936, the site chosen being in the island of Hokkaido. Finally, the work on meteorological physics has been continued, and the work on the Fe+ laboratory spectrum has been brought to a successful conclusion, 58 new multiple terms and 157 levels having been determined.
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Solar Physics Observatory, Cambridge. Nature 136, 906 (1935). https://doi.org/10.1038/136906a0
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DOI: https://doi.org/10.1038/136906a0