NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: sextant for use on land
From: Paul Hirose
Date: 2006 Aug 12, 23:23 -0500
James R. Van Zandt wrote:
>
> 4) At least some of these call for 28 VDC. Is that only required for
> the averager, or also to illuminate the bubble or for some other
> function?
Long after they were first built, some Kollsman periscopic bubble
sextants were fitted with electronic averagers. I saw one in the 1990s
when I was in the USAF. Every other bubble sextant I know about uses
electric power for illumination only. The Kollsman I bought on eBay has
the original clockwork averager. An attached sticker says it was
repaired in 1994. It needs 28 V to take star shots, since the bubble is
invisible at night. All it would take is a few 6 V lantern batteries and
some odds and ends from Radio Shack, but I have never gotten around to
trying that.
On the other hand, the older AN5851 is nuclear powered (luminous paint
in the bubble cell) and uses external power for exterior illumination
only. I don't own one, but have seen one user say it's not worth the
bother hooking up the power pack, that it's easier to use a penlight to
read the scales.
Back in January 2003 I posted some results with my two bubble sextants
to the old Nav-L mailing list:
http://www.i-DEADLINK-com/lists/navigation/0301/
The first is at the top of the page, and there's another posting about
halfway down ("A-12 & Kollsman test results").
If you're interested in bubble sextants, I recommend buying an old copy
of U.S. Air Force Manual 51-40, Air Navigation. It was written for the
user of these sextants. The 1955 edition I have contains instructions
for the Kollsman periscopic, the AN5851 types, and even the A-10 (but
not the A-12). Note that the book is split into more than one volume. I
didn't know that when I bought mine on eBay, but fortunately the one I
got was the volume covering celestial nav.
--
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From: Paul Hirose
Date: 2006 Aug 12, 23:23 -0500
James R. Van Zandt wrote:
>
> 4) At least some of these call for 28 VDC. Is that only required for
> the averager, or also to illuminate the bubble or for some other
> function?
Long after they were first built, some Kollsman periscopic bubble
sextants were fitted with electronic averagers. I saw one in the 1990s
when I was in the USAF. Every other bubble sextant I know about uses
electric power for illumination only. The Kollsman I bought on eBay has
the original clockwork averager. An attached sticker says it was
repaired in 1994. It needs 28 V to take star shots, since the bubble is
invisible at night. All it would take is a few 6 V lantern batteries and
some odds and ends from Radio Shack, but I have never gotten around to
trying that.
On the other hand, the older AN5851 is nuclear powered (luminous paint
in the bubble cell) and uses external power for exterior illumination
only. I don't own one, but have seen one user say it's not worth the
bother hooking up the power pack, that it's easier to use a penlight to
read the scales.
Back in January 2003 I posted some results with my two bubble sextants
to the old Nav-L mailing list:
http://www.i-DEADLINK-com/lists/navigation/0301/
The first is at the top of the page, and there's another posting about
halfway down ("A-12 & Kollsman test results").
If you're interested in bubble sextants, I recommend buying an old copy
of U.S. Air Force Manual 51-40, Air Navigation. It was written for the
user of these sextants. The 1955 edition I have contains instructions
for the Kollsman periscopic, the AN5851 types, and even the A-10 (but
not the A-12). Note that the book is split into more than one volume. I
didn't know that when I bought mine on eBay, but fortunately the one I
got was the volume covering celestial nav.
--
I block messages that contain attachments or HTML.
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---
