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Mr. Pigott's Investigation of the Changes
Its rotation on its axis was, in 1796, estimated at 6234 days, from a mean of six observations of its greatest and least brightness. Here follow about 26 similar determinations, most of them the results of very accurate observations; and as they probably will in future be compared with others, I have examined them repeatedly with the utmost care, attending particularly to the progression of their changes.
Table I.
| Dates when at its greatest Brightness. |
Magnitudes | Dates when at its least Brightness |
Magnitudes | |||
| 1796. | September 17 | 5 | 1796. | September 3 | 6 | |
| November 13 | 5 | – | October 22 – | 6 | ||
| 1797. | May 14 : – | 5 | + | 1797. | July 10 – – | 5.6 |
| August 7 – | 5 | September 15 | 6 | |||
| October 15 – | 6.5 | November 6 | 6 | |||
| 1798. | July 29 – | 5 | + | 1798. | July 10 – – | 6 |
| October 25 – | 5.6 | September 15 | 9.0 | |||
| December 5 : : | 5.6 | November 10 | 6 | |||
| 1799. | June 1 : : – | 6.5 | 1799. | July 4 – | 7 | |
| August 7 – | 5 | September 16 | 6 | |||
| October 11 – | 5 | + | November 5 : | 6.7 | ||
| 1801. | July 14 : – | 5 | 1801. | June (middle) : | 6 | |
| September 24 | 5 | August 21 – | 6.7 | |||
| October 16 – | 6.5 | |||||
The + and — annexed to the magnitudes denote them to be more or less bright; the doubtful results are marked with dots; all the others are esteemed exact, except those of August 7, 1797, and August 21, 1801, which are in a small degree less so. From these determinations the rotation on its axis may be computed as follows.
