NavList:

Ed,

This is clever.  I've been trying to construct a 'dry' AH because I always seem to spill the fluids I'm using or otherwise have a mess to clean up.  Also the depth of the container (usually my Davis AH) requires a Sun altitude that leaves little useable reflecting area given the contrained times and azmuths available from a comfy shooting location on my condo deck, especially this time of year at my latitude (N47 35).  Using a shallower fluid container (e.g., the cover of the Davis AH) is an alternative but that's when my unsteady hand results in messey liquid spills.  I've also tried constructing a dry AH using a self-leveling platform driven by quaternions extracted from a 9 degrees of freedom (9-DOF) breakout board contolled by a microprocessor but I've yet to achieve a useable level of platform stability and levelness.

The platters from my many retired hard drives will now have something useful to do in their retirement.  Many thanks for sharing this idea.  It's now on my list of winter projects (along with too many others).

Cheers,

Jim.