NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Bris accuracy?
From: Doug Royer
Date: 2004 Nov 8, 10:49 -0800
From: Doug Royer
Date: 2004 Nov 8, 10:49 -0800
"I never knew about Bris sextant before it was mentioned on this list." That is the great thing about being a member of this list.Every once in a while,for each of us,there are little nuggets of info or ideas brought forth that make the list invaliable. I enjoy the exchanges and learned to fine tune certain procedures from discussions on this list.I'm glad I could give something back. As for the accuracy of the Bris in actual use I include the below. The inventer of this device used it on a trans-atlantic voyage(east to west;northern hem to southern hem and back)on a small boat.Good enough results for him and his wife to find their way to and from every where they needed to go during that voyage.Although he still carried his Cassens and Plath sextant along. Here are some results from last Sat. (11-06-04) and Sun. (11-07-04) positions useing the Bris. 3 differant alts of the Sun taken at 3 differant times of day from the same terrestial position.No averaging used as when the image of the Sun is where it needs to be(on the Bris) as according to the user instructions the time is noted and each sight is reduced to find the LOP. Both days the position by GPS coordinates: 32* 49' 24" N 116* 49' 49" W 11-06-04 most probable position.2 alts and times during the morning hrs and 1 alt and time during the late afternoon hrs: 32* 49' 31" N 116* 50' 07" W This is between 600 - 650 yds differance at a bearing of 288* T from the GPS pos. 11-07-04 most probable position. 1 alt and time in the morning hrs and 2 alts and times during the later afternoon hrs: 32* 49' 36" N 116* 49' 43' W This is between 400 - 500 yds differance at a bearing of 012* T from the GPS pos. This is only the 4th weekend I've had to play with this instument and the "accuracy" of the MPP is getting better the more I use the instrument.