NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: astrocompass still in use
From: Robert Eno
Date: 2002 Sep 26, 21:55 -0400
From: Robert Eno
Date: 2002 Sep 26, 21:55 -0400
Interesting application. How on earth did you manage to keep your astrocompass perfectly level whilst it was mounted on your boat? Robert ----- Original Message ----- From:To: Sent: Thursday, September 26, 2002 8:15 PM Subject: Re: astrocompass still in use > Quoting Paul Hirose : > > > The astrocompass lives on. A major utility company in California > > allows engineers and architects to borrow one to evaluate solar access > > to a building site. Here is their online manual: > > > > > http://www.pge.com/003_save_energy/003c_edu_train/pec/toolbox/tll/app_notes/ astr > o_comp.shtml > > > I have an Astrocompass and I have fixed up a mounting on my boat for it. I used > it about a year ago to check the Deviation of the boat's compass and a very > interesting afternoons exercise it was too. I wonder if anyone else has found a > use for this old faithful. > First the instrument was mounted and levelled. The Latitude was set on the > micrometer scale and the Declination of the Sun set very roughly on the > sighting bar. The LHA of the Sun changes slowly so I wrote a simple program on > a Ti82 calculator to give the value to set on the LHA drum for every minute of > time and this was re-adjusted accordingly. > Next the boat was carefully steered on 12 different COMPASS headings at 30 > deg increments and the Astrocompass rotated to bring the Sun's shadow of the > sighting bar onto the plastic graticule. At this point the TRUE direction of > the boat was read of the base scale. Adding Variation to this data produces a > list values for plotting the Deviation correction graph. > I have no idea of the origin of this instrument and I would like to hear if > anyone in the group does. I was taught how to use it in a Coastal Command > Lancaster many years ago and my instructor then had used one when flying over > the Libyan dessert during the war. His magnetic compass had been destroyed by > an enemy bullet. > I have an instruction book. If any one would like a copy my email is > jcs@cwcom.net. > > Clive Sutherland. > Wantage, (where King Alfred burnt the cakes). > 51deg 38.2 min N 001deg 24.5min W > >