1801 元旦發現穀神星

mca

1801 年的元旦，在意大利的皮亞齊無意中發現了 Ceres 穀神星。Ceres 的直徑約 950 公里，亮度  6.6 至 9.3 等，本來是小行星 1  號，但在 IAU 2006 年的定義修正之下，Ceres 不再是小行星而編入矮行星 (dwarf planet) 族，即是沒有 "小行星 1 號" 了，小行星族由 Pallas (智神星 / 小行星 2 號) 開始。

發現穀神星的 The Palermo circle


This instrument, built by Jesse Ramsden (1735-1800) of London, was used by Giuseppe Piazzi (1746-1826) to obtain precise measurements of stellar positions, with an accuracy of a few seconds of arc after observing each star for at least two nights. In the process, Piazzi unexpectedly discovered the first asteroid, 1 Ceres, in 1801. The telescope has a 7.5-cm objective lens. The altitude scale (5 feet in diameter) was read with the aid of two diametrically opposed micrometer microscopes; the azimuth scale (3 feet in diameter) was also read by means of a micrometer microscope.

穀神星的發現經過
http://www.staff.science.uu.nl/~ ... loads/text2_04a.pdf

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Auld Lang Syne (Sissel in Swedish TV, 12.30.2008)
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