中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
2′,4′,6′-三甲基苯乙酮 | 2,4,6-Trimethylacetophenone | 1667-01-2 | C11H14O | 162.232 |
The planispheric astrolabe occupies a special place among early scientific instruments because of its mathematical sophistication, its elegant appearance, and its usefulness to astronomers in pre-telescopic times. The operation of the astrolabe is based on the mathematical properties of stereographic projection, concepts that were understood by the time of Ptolemy in the second century