NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Simplified Bris Sextant
From: Alexandre Eremenko
Date: 2012 May 7, 23:15 -0400
From: Alexandre Eremenko
Date: 2012 May 7, 23:15 -0400
Greg, I have to say that I do not find this Bris very practical. It is rather a toy than a navigation device. The reason is that you have to wait for these pre-assigned moments, there are few of them during the day, and at these moments Sun can be obscured by a cloud, or you can be busy with something else, or just miss the moment. I am interested to hear from a list member who managed to gratuate his/her Bris sextant:-) Alex. On Mon, 7 May 2012, Greg Rudzinski wrote: > > Making a simplified Bris Sextant only requires gluing two microscope slides together with a gap at one end. The larger the gap the greater the angular deflection of the reflected Sun. I used a 0.7 mm pencil lead to set a gap and got 1* 57.8' of deflection. Inspect the linked image and you will see that the reflected image is the sum of four images one on top of the other. This must be from the front and back surface reflections from each slide. The best a navigator can probably hope for is 1' to 2' of precision on a home made version. Still this is pretty good for something that can get lost in a shirt pocket. > > Greg Rudzinski > ---------------------------------------------------------------- > NavList message boards and member settings: www.fer3.com/NavList > Members may optionally receive posts by email. > To cancel email delivery, send a message to NoMail[at]fer3.com > ---------------------------------------------------------------- > > > > > > > Attached File: http://fer3.com/arc/img/119461.f1-img_1189.jpg > > > : http://fer3.com/arc/m2.aspx?i=119461 > > >