Our Astronomical Column

Abstract

THE SUNSPOT CURVE AND EPOCHS.—The great importance of collecting as many facts as possible regarding solar activity, and revising them from time to time as new information is gathered, is clearly shown by the paramount rôle that the sun plays in causing the numerous variations in meteorological phenomena. Wolf's relative numbers have been, and are now, so commonly used when reference has to be made to solar activity that it is of the first importance that such a series of values should be as near correct as possible. It is with great satisfaction, therefore, that we note that Wolfer has so diligently continued the useful work, ably begun by Wolf, that he has now published (Meteorologische Zeitschrift, May, 1902) a new set of values carefully revised and brought up to date. As he remarks, an examination of the original manuscript at the observatory with various published tables has shown that a great number of differences and printer's errors have crept in, suggesting that it is time that a new edition was published. This reduction has been very carefully made by Wolfer and his assistant, each making the computations twice. In addition to the observed relative numbers, the paper gives smoothed relative numbers, while a third table shows the epochs of maxima and minima with their corresponding weights; the addition of the weights to the dates of these epochs is a very valuable piece of information which will add to the utility of the earlier epochs.