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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Amundsen at the South Pole
From: Randall Morrow
Date: 2011 Dec 19, 07:22 -0800
I zoomed in on the photo from the Amundsen camp to 500 % and it seems to me that it is probably a mirror on a 3-screw leveling plate and no liquid of any kind is involved. As liquids seek their own level no screws would have been needed, and since the device is fairly large and shallow it does not seem likely that it was designed to hold any liquid. The few vintage mercury horizons I have seen in illustrations appear to be in the form of a box, and are very small when compared with the Amundsen example. The possibility of spilling the irreplaceable mercury contents may have made such a shallow basis too risky. The Freiberger a.h. is a good match for the device seen in this photo.
Randy
Randall F Morrow PT
Kern County - Bakersfield
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Looking at the photo I see that the AH has leveling screws which allow one to have a large surface area without large quantities of liquid.
From: Randall Morrow
Date: 2011 Dec 19, 07:22 -0800
I zoomed in on the photo from the Amundsen camp to 500 % and it seems to me that it is probably a mirror on a 3-screw leveling plate and no liquid of any kind is involved. As liquids seek their own level no screws would have been needed, and since the device is fairly large and shallow it does not seem likely that it was designed to hold any liquid. The few vintage mercury horizons I have seen in illustrations appear to be in the form of a box, and are very small when compared with the Amundsen example. The possibility of spilling the irreplaceable mercury contents may have made such a shallow basis too risky. The Freiberger a.h. is a good match for the device seen in this photo.
Randy
Randall F Morrow PT
Kern County - Bakersfield
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| "David Fleming"
<d.l.fleming.1@gmail.com>
Sent by: navlist-bounce@fer3.com 12/17/2011 10:11 AM
|
|
Looking at the photo I see that the AH has leveling screws which allow one to have a large surface area without large quantities of liquid.
The assistant is hovering over the AH to get it level.
I can not tell from the photo what liquid is being used.
Wikipedia tells me summertime high temperatures in Antartica by the coast might be in the +5 to +15 degrees Centigrade. What that means at the pole is a guess but liquid mercury strikes me as not improbable.
Dave Fleming
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