The revival of solar activity after Maunder minimum in reports and observations of E. Manfredi
✍ Scribed by E. Baiada; R. Merighi
- Publisher
- Springer
- Year
- 1982
- Tongue
- English
- Weight
- 265 KB
- Volume
- 77
- Category
- Article
- ISSN
- 0038-0938
No coin nor oath required. For personal study only.
✦ Synopsis
We present information, published here for the first time, concerning observations of sunspots made at the beginning of the XVIIIth century. The information has been taken from specola's archives in Bologna. It concerns the years just after the end of the Maunder minimum. The data confirms the presence of a double maximum in 1704-1707, and shows a high asymmetry in sunspots latitude distribution, possibly related to the abnormal Sun activityin the second half of XVIIth century.
This paragraph was written by E. Manfredi, astronomer of the Specola Marsiliana, in his book Descrizione d' alcune macchie scoperte nel Sole l' anno 1703 .... publishing the first scientific result of his work. The period of solar inactivity to which Manfredi refers, is now known as Maunder's minimum. The end of the period can be traced to the first years of XVIIIth century, so solar observations from 1700 to 1710, years of Specola Marsiliana activity, are of particular interest.
2. Historical References
Bologna, whose famous University was still limited to scholastic methods of research, lost its only internationally important scientist when G. D. Cassini left for the Paris Observatory. * We observed (...) with the utmost care to see if any new phenomena appeared on the Sun. In fact it seems that, after Galileo and P. Scheiner's discovery of the sunspots they have been seen with decreasing frequency. Around 1625 sometimes as many as fifty spots appeared together, and towards the middle of the last century the absence or even low number of spots was considered quite extraordinary. Today, on the contrary, we consider unusual the appearance of even a single sunspot. It would seem as if these spectacles appeared deliberately in the century during which the wonderful instrument for observing them was invented.