| 摘要 |
<p>The slide rule is for calculating astronomical positions. It has a rigid support with a central shaft, on which is placed an assembly of cards for each latitude in two degree steps. Each card is a transparent and synthetic disc showing projections of arcs of azimuth in 5 degree steps and graduated 0 to 360 degrees. The full card set has 33 cards. There is a similar disc graduated 0 to 360 degrees and 0 hrs to 24 hrs in sidereal time and with a representation of a stereographic projection of the zodiac band on a plane.</p> |
