LOP plotting question

[Rumata]

When you plot your TOWARD or AWAY distance, do you account for the change in distance between degrees of longitude? 

Darn-it, Bigbill... you just made me doubt my own work - great question.  I have been using great circle distance and use latitude to ascertain distance. (Using distance from right or left margin.)  In other words I use full nautical miles without compensation for divergence (or convergence) of latitude.  But then again I live at 10 degrees north and do all my observations here.  There is not much difference between true Nautical miles and max seconds of longitude in meters which vary with latitude..

I found the technique described in Mixter, 1942, article 195, how to make your own plotting sheet helpful. In particular, on page 108, it says "...the diagonal gives the scale of latitude OR DISTANCE FOR USE ANYWHERE ON THE PLOTTING SHEET." On the UPS lattitude scale looks reasonable.