NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Bubble sextant trials
From: Robert Eno
Date: 2007 Feb 14, 14:03 -0500
From: Robert Eno
Date: 2007 Feb 14, 14:03 -0500
Alex wrote: > Further remarks. The averager seems useless for observations from > a stable platform. Besides, it is very heavy, and my hands get tired > in the two minutes needed for an observation. So Ken's idea to cut > the averager off seems reasonable for backyard observations. Eno comments: The averager is of no use for land-based obserations and in fact using it will lessen the accuracy of your shots. There is simply no practical value to using the averager. Alex wrote > I wonder if the averager will help on a small boat. Eno comments: Doubtful. Bubble sextant observations at sea are at best, a crap shoot; at worst, useless; unless you are taking observations on a flat-calm sea. The averager was designed for the relatively stable platform of large aircaft and not pitching, yawing vessels at sea. I suppose in a pinch, bubble sextant observations at sea would be better than no observations at all but one would have to draw a 20 mile circle of error around the resultant position. Alex wrote: > > I noticed that something strange happens with the bubble: > as I observe, small bubbles come from 10 oclock direction and > join my main bubble. So it grows:-) > Do I have to rotate the bubble wheel anticlockwise (relaxing the > tension > of the membrane) after the size of the bubble is adjusted? Eno comments: Yes. Once you have formed the bubble to the desired size, you must back off the tension on the bubble adjustment wheel. This is especially so with the C.Plath SOLD design. In very cold weather, you will notice that the bubble gets larger and has to be adjusted to compensate for this. Alex wrote: > Will try some stars if weather permits. Eno comments: And this my friend, will be the point at which you will appreciate the beauty of the bubble chamber illumination system of the MK IX series and why it is far superior to other bubble illumination systems. Robert --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---