NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: davis a.h.
From: Joe Shields
Date: 2001 Apr 24, 11:20 AM
From: Joe Shields
Date: 2001 Apr 24, 11:20 AM
Having used a shallow dish of water for many years before purchasing a Davis artificial horizon, the Davis a.h. is much better. Not only for the wind protection provided by the enclosure, but also the tinted glass cuts down on the glare providing a crisper, more comfortable-to-look-at disc. I guess the one disadvantage of the pan-of-water type a.h. over a bubble type a.h. is its limitation to lower altitude sights. For instance, I can't practice noon shots in my back yard except during Winter months (brrrrrr...). Of course in the Summer, with our sailing club situated on the North shore of our little (~1nm across) man-made lake, short-dip corrected sights are the best. -----Original Message----- From Doug Sterrett [mailto:dwsterrett@EARTHLINK.NET] Sent: Tuesday, April 24, 2001 12:35 PM To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM Subject: Re: Astra IIIB John, please caution people that mercury is highly poisonous and very dangerous for laymen to handle. In many states it is a controlled substance. It is also extremely expensive. Humbly submitted by Doug At 12:34 AM 4/25/01 +1000, you wrote: >a shallow pan of mercury is perfect>cheers, >John > >At 21:34 23/04/2001 -0700, Yves Arrouye wrote: >> > The practice bubble horizon is difficult to use. There is no >> > magnification. >> > The slit aperture makes me see double of the reference line >> > in the sight. >> > Combine that with trying to hold the sextant steady so the bubble is >> > centered while adjusting the sight ... it can be frustrating. >> >>I know, I tried it. What's very frustrating is how any small movement makes >>the bubble go away. But then, I didn't seem to have much success with a pan >>of water in my garden either. Maybe oil would be better? Anyway, the bubble >>horizon is on order, and I'll see what my first sights will be. Not good I >>imagine... >> >>YA