NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
First mirror artifical horizon test
From: Patrick Goold
Date: 2011 Mar 25, 18:10 -0400
From: Patrick Goold
Date: 2011 Mar 25, 18:10 -0400
A break in the weather allowed me to take a series of sun sights with my mirror assembly sitting side by side with my Davis artificial horizon.
It took me 15 minutes to level the mirror assembly. Fred and Bill are definitely right that a three-leg arrangement would be superior. With four I repeatedly leveled the base only to find that it would rock on two of the legs. Secondly, there was evidence that the polypropylene board was not rigid enough and that the bolts were loose in their threads. Both effects were part of the cause of the difficulty of leveling the assemble. I will be rebuilding this with three legs, a thicker base, and levelers more carefully machined than bolts from the local hardware store.
Still, against the odds I did manage to get a decent series of sights. Obviously, I could not simultaneously shoot off the mirror assembly and off the Davis AH. I went back and forth between them and then plotted the readings against time to see if the lines overlapped. The result (attached), I think, is promising. The approach is feasible but the assembly I have needs to be thoroughly reworked to facilitate reliably stable leveling.
Patrick
It took me 15 minutes to level the mirror assembly. Fred and Bill are definitely right that a three-leg arrangement would be superior. With four I repeatedly leveled the base only to find that it would rock on two of the legs. Secondly, there was evidence that the polypropylene board was not rigid enough and that the bolts were loose in their threads. Both effects were part of the cause of the difficulty of leveling the assemble. I will be rebuilding this with three legs, a thicker base, and levelers more carefully machined than bolts from the local hardware store.
Still, against the odds I did manage to get a decent series of sights. Obviously, I could not simultaneously shoot off the mirror assembly and off the Davis AH. I went back and forth between them and then plotted the readings against time to see if the lines overlapped. The result (attached), I think, is promising. The approach is feasible but the assembly I have needs to be thoroughly reworked to facilitate reliably stable leveling.
Patrick
File:
