TO SAVE time the navigator sometimes sets a watch to keep approximate local apparent time. Similarly, aviators are already using two watches, one set to Greenwich civil time and the other to Greenwich sidereal time. These are makeshifts and unsatisfactory. However, if we could find quickly and accurately both G.C.T. and local apparent time, or both G.C.T. and G.S.T., we would be getting somewhere. With various accurate short methods of computing the altitude, one of the largest factors in working the line of position now consists of finding the local hour angle of the body used. In order to reduce the time and labor for finding the hour angle in aerial navigation, we propose an adjustable rate clock. The manufacturer might say that it is impracticable to make, and some might say it is too complicated to use, or unnecessary. However, the idea is advanced for what it is worth, and thought on the subject by others might help to develop a short cut in finding the hour angle.
Possibilities of an Adjustable Rate Clock
By Lieutenant Commander P. V. H. Weems, U. S. Navy