Mount Wilson Observatory


spots. tt is to be noted that sunspot-numbers such as those from Ztirich can be obtained from the number of groups and spots given in the Table by the formula N=k (10g+s), where k for Mount Wilson is about 0.7. Mount Wilson Observatory is now supplying corrections and additions to the sunspot-data which are broadcast in the URSIgram. So far as possible, these additional and corrected values will be used in this tabular summary and will be designated as such in footnotes to the Table. Beginning January 15, 1936, all areas on the Sun with temperatures much lower than their surroundings will be counted as sunspots at the Mount Wilson Observatory. The value of k for Mount Wilson used in forming the Wolf numbers will thus be made smaller than heretofore and more nearly constant during the cycle. Beginning January 1, 1934, the magnetic information of the URSIgram is for Cheltenham, Maryland, instead of Tucson, Arizona. In addition to this change in observatory, the data cover the 24 hours ending 8 A.M., 75 ø west meridian mean time, instead of the 24 hours ending at 7 A.M., 105 ø west meridian mean time. The columns headed solar constant show (1) the value in calories of the solar constant, and (2) by letters s, f, and u whether the determination was satisfactory, fair, or unsatisfactory, respectively. In accordance with information received from Dr. C. G. Abbot, Secretary of the Smithsonian Institution, transfer from Table Mountain to Montezuma solar-constant values was made as of October 23, 1934. Table Mountain for a considerable time has been 0.012 calorie above Montezuma, and above the scale of 1913 to 1930. Hence the value of October 23, 1934, and succeeding values are on a scale 0.012 calorie lower than previous ones. The table of Kennelly-Heaviside Layer heights is self-explanatory.

Cite this paper

@inproceedings{Ennis2007MountWO, title={Mount Wilson Observatory}, author={Calvin S Ennis and MOUNT WILSON OBSERVATORY}, year={2007} }