A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2016 Mar 12, 09:57 -0800
Use the dark scope ocular lens filter cap on the ocular of the scope. To do this take off the scope rubber eye cup then press fit the dark filter cap on. Set sextant to zero. Now observe Sun for determine index error. If more tha 1' then it is worth using the horizon mirror adjustment tool to take the error out. While you are at it then check side error. I like to leave a little bit of side error in so that the reflected Sun image doesn't get lost behind the direct image.
You may want to select shades with scope off the sextant. Once selected mark the shade combinations with whiteout for future use on a bright Sun. It is also easier to find the Sun in the artificial horizon without the scope on and to then bring the Sun down with index arm. Put the scope back on for the actual observation. Another way is to figure Hc with USNO data and double the value as an artificial horizon preset. Both Suns should then be within the field of view.
From: Bill Lionheart
Date: 2016 Mar 12, 01:15 -0800