Making a Backstaff


Put up a few photos, on a.b.p.woodworking, showing part of the process of making a Backstaff, as well as a little bit about the shop and the jigs I built to do the job.
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of work. I'll also show my ignorance and ask what you use it for? :-)
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Lowell Holmes wrote:

Hi Lowell,
Actually it's my fault - I should have put in a description. A Backstaff was used by Mariners in the 1600-1800 time period to measure the altitude of the sun.
http://images.google.com/imgres?imgurl=http://www.discoveringbristol.org.uk/90images/11/2878.jpg&imgrefurl=http://www.discoveringbristol.org.uk/results.php%3Fs%3D%26categoryId%255B%255D%3D37%26p%3D16&h &w&sz=4&tbnid=xfkbwfXh4XIJ:&tbnht&tbnws&hl=en&startV&prev=/images%3Fq%3Dbackstaff%26start%3D40%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DN
has an etching. The idea was to put the sun at your back, and slide shadow vanes along the arcs until the shadow the sun makes is even with the horizon which yuo can see in a slit through the sight vane.
You can see other stuff I make, here:
http://home.comcast.net/~saville/backstaffhome.html
Gregg
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http://images.google.com/imgres?imgurl=http://www.discoveringbristol.org.uk/90images/11/2878.jpg&imgrefurl=http://www.discoveringbristol.org.uk/results.php%3Fs%3D%26categoryId%255B%255D%3D37%26p%3D16&h &w&sz=4&tbnid=xfkbwfXh4XIJ:&tbnht&tbnws&hl=en&startV&prev=/images%3Fq%3Dbackstaff%26start%3D40%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DN
I should have recognized it. I was a Quartermaster in the Navy and later while recreational sailing, use a sextant. I noted the similarity of the Backstaff to an Octant. I should have snapped to it.
During the time period you mentioned, reliable time pieces were either non-existent or quite expensive. Local apparent noon was one of the few observations they had. Have you read Dava Sobel's book, "Longitude"? John Harrison was a wood worker and his first clocks were made of wood. I'm sure I'm telling you what you already know.
Patrick O'Brian's characters had something to say about chronometers in his novels.
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Lowell Holmes wrote:

Thank you for your service in the Navy.
I would hardly expect a modern Navy veteran - even a QM - to recognize a Backstaff by name ;^)

Several times ;^)

Fascinating to me that they knew enough about wood to make gears that stayed true, or that they somehow accounted for the humidity changes more in one direction than another.

Yeah and I read what those characters had to say - about 6 times each ;^) Now that you mention it, maybe I'm due for a 7th....
Cheers,
Gregg
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On Sun, 11 Dec 2005 18:13:20 -0500, Saville wrote:

It was really rude of O'Brian to up and die on us.
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Australopithecus scobis wrote:

Having had no nautical experience, I had to read the books while logged on to the Internet so I could figure out what the terms were. Seems like I had to do a Google search every third page.
Dick Durbin
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Another excuse for shopping at Lee Valley: <http://www.leevalley.com/gifts/page.aspx?c=1&pP551&cat=4,104,53216&ap=1>
Mike
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Michael Daly wrote:

Hi Mike,
yeah well at least O'Brian used the same terms every single book. Without adding new ones once you got past the middle of the series.
Sad to say I found the books getting repetitive after the 2/3's point. Though the second to last was pretty good.
The last though ...well....I suspect it wasn't he who wrote it. The characters didn't "sound" like themselves.
Gregg
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wrote:

last book. OH WELL!
I may read some of the early ones again. I agree the last 4 or 5 books were not as fresh as the earlier ones.
I found the doctor to be a bit contrived in the first book, having Irish and Catalan ancestors. That character sure added a lot to the richness of the series though. I almost never found where Catalonia is until the Smithsonian magazines published an article about the anchovies from Catalonia.
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