A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Gary LaPook
Date: 2015 Dec 24, 23:59 -0800
The CP-300/U allows you to slide the altitude curve disk up or down 5 degrees to set your exact latitude but does this make a practical difference? For stars north or south then each degree of latitude scale change makes a degree of altitude but there is little change on azimuths near east or west. On north and south you could just mentally make that adjustment. The maximut error in altitude with the 2102-D is just this five degrees. If you are just looking with your eye nobody can detect a five degree difference. If looking through your sextant scope to find a star at twilight, as long as its field of view is greater than 5 degrees you will find the star by sweeping the sextant along the horizon in the general direction given by the star finder. If the field of view is less then two sweeps of the horizon, the first with the horizon near the bottom of the field and the second sweep with the horizon near the top.