NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Bygrave formula
From: Hanno Ix
Date: 2014 Jun 9, 11:43 -0700
After I have seen them I will give you more details on the cursor/pointer rolls
However, please hold off on the sin(x) version for now. I am working on a study that
compares scale lengths with a "1 mm for 1 arcmin" scale of different trig functions.
And so far, sin(), cos(), sec() and csec() don't come out too good, tan(0) and cot(0)
are OK: tan() / cot() require 30 meters - sin() etc require 64 meters!
Next will be the haversine. My guess: very long scale as well.
From: Hanno Ix
Date: 2014 Jun 9, 11:43 -0700
Francis:
Cannot wait to see the missed attachments! After I have seen them I will give you more details on the cursor/pointer rolls
as I imagine them.
are OK: tan() / cot() require 30 meters - sin() etc require 64 meters!
Next will be the haversine. My guess: very long scale as well.
That may not be the end for sin() / cos(), though.
Sight seeing reduction formulas can be expresses in sin() / cos() alone. So one scale is sufficient.
They cannot be expressed by tan() / cot() alone. ( At least I have not seen such a formulation yet.
If anyone did PLEASE send them to me! ) So we will need combinations of tan() / cot()
and sin() / cos() i.e. at least two scales as for instance on the Bygrave.
Consequently, even if we do not need "1mm for 1 arcmin" on the sin() / cos() in such a
combination for an accurate end result the total lengths of two scales might come
close to the length of a single hi-res sin() / cos() scale.
If anyone did PLEASE send them to me! ) So we will need combinations of tan() / cot()
and sin() / cos() i.e. at least two scales as for instance on the Bygrave.
Consequently, even if we do not need "1mm for 1 arcmin" on the sin() / cos() in such a
combination for an accurate end result the total lengths of two scales might come
close to the length of a single hi-res sin() / cos() scale.
As I mentioned before, though, a Fuller version with 1 or 2 scales and with
"1mm for 1 arcmin" scales will be quite a bit larger than the Bygrave as is we know it.
"1mm for 1 arcmin" scales will be quite a bit larger than the Bygrave as is we know it.
But only a Bygrave with a "1mm for 1 arcmin" resolution would be a truly fair comparison.
I am attracted to the inherent simplicity of the Fuller, both in concept and construction.
My wish is to find a method of construction of it that fits the mechanical capabilities
of a lot of CelNav aficionados even if it would be bigger than the Bygrave.
The Bygrave will always have its own fans.
My wish is to find a method of construction of it that fits the mechanical capabilities
of a lot of CelNav aficionados even if it would be bigger than the Bygrave.
The Bygrave will always have its own fans.
Hanno
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PS: Your attachments just arrived - thx!
On Sun, Jun 8, 2014 at 11:11 PM, Francis Upchurch <NoReply_Upchurch@fer3.com> wrote:
sorry,
not sure if attachments got through?
Am I doing something wrong?
Francis
