This page allows you to compute sight reductions. As an example try entering this example from the text. L= 26.12 S. Note that the minutes and seconds must be changed to decimals as done here. D=29.03 N. H=44.97 E. The result z is 70.01472 and Hc = 19.98528. P is 60.97 and Z is 45.8411 (but this may not be correct). The degrees and minutes input isn't working yet but the output is displayed in decimal and degrees and minutes.