NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: problems with artifical horizons
From: Alexandre Eremenko
Date: 2012 Mar 20, 22:02 -0400
From: Alexandre Eremenko
Date: 2012 Mar 20, 22:02 -0400
Alan, 1. As you already measured the alt of the sun before, you could preset your sextant on this altitude. Pre-setting sextant on an approximate alt frequently helps, espesially if you observe through the holes in the clouds, and have little time to search the sun. The approximate alt can be computed with a) star globe, if you have one (Russian manuals recommend this) b) a star finder (there are many types, soe of them cheap and handy). c) special tables (the Complete on board Celestial Navigator has them). In general, tis is an excellent thing, don't know why they do not cell paper copy anymore. But you can print and bound yourself). 2. I also use the following method sometimes. With real or artificial horizon, especially with stars. Take your sextant upside down, point it on the Sun, so that you see it through your horizon mirror (don't forget the shade). This is easy, becasuse you feel where the Sun is with your face. Then swing the arc to catch the reflected Sun. Once you catch it, take the sextant in the normal way. This is easier with Davis if you put its own filter on it, and remove the sextan Index filter from the field of view, while searching. Don't forget to put it back when you invert the sextant to hold it in the normal way. 3. Another method. Remove the telescope. This helps in searching. Especialy if your telescope is a strong one with a small field of view. Once you catch the Sun, put the telescope back. Hope some of these techniques help. Alex.