20pc是多少ly？
20pc = 65.2313ly
是65.2313ly，所以說成65ly也沒問題——四捨五入的誤差在0.5%以內。
反過來，20ly是多少pc？
20ly = 6.132pc
計算公式: ly = pc × 3.261564
該數值前後的 pc → ly
2 pc6.5231ly
4 pc13.0463ly
6 pc19.5694ly
8 pc26.0925ly
10 pc32.6156ly
12 pc39.1388ly
14 pc45.6619ly
16 pc52.185ly
18 pc58.7081ly
20 pc65.2313ly
22 pc71.7544ly
24 pc78.2775ly
26 pc84.8007ly
28 pc91.3238ly
30 pc97.8469ly
32 pc104.37ly
34 pc110.8932ly
36 pc117.4163ly
38 pc123.9394ly
40 pc130.4626ly