NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Hybrid Artificial Horizon
From: Bill B
Date: 2008 Sep 14, 01:15 -0400
From: Bill B
Date: 2008 Sep 14, 01:15 -0400
George wrote > I don't think that would work. With an open bottom, all the form-stability > of a flat box shape would be lost. It would be a bit similar (but the other > way up) to the loss of stability that occurs on roll-on vessels when they > get water sloshing around on the wide vehicle deck. Speaking of sloshing water, was this device protected from the wind in some manner? It is a significant problem if the water itself is not perfectly still. I had very good results with a roughly 10" x 4" plastic storage container (with a positive 4-latch and O-ring-seal lid) filled with 50-weight motor oil with black woodworker's oil-soluble dye added to the oil. 3/4 full, it provided a long surface good for low altitude observations. The ink-black oil had no problems reflecting the navigational stars even with some light pollution. The drawbacks: Wind would effect the surface of the oil, so it needed a glass cover. No matter how careful I was about cleaning the rim of the vessel, oil got on the outer regions of the glass and cleaning it up to my standard was a pain in the rear. If I put small shims between the glass and the vessel rim to stop the oil transfer, wind could still cause minor ripples on the oil surface. Testing was necessary to be certain the faces of the glass were parallel. The oil was so highly reflective, it was too easy to mistake the image reflected from the cover-glass surface for the image reflected from the oil surface. The glass surface was not necessarily parallel to the oil surface. On the plus side, this could assist in distinguishing between the glass and oil reflected images. Not a big deal to use an inexpensive hardware-store bubble level to get the container and glass parallel within cel-nav tolerances. Summary: Upsides: It is cheap, it works well, and no problems with water vapor condensing on the glass during sun shots. Downsides: It is messy, and you don't want to spill any of the oil/dye mixture on your garments, shoes, floor, driveway or lawn. Bill B. --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---