A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Position-Finding
From: Herman Dekker
Date: 2017 Dec 25, 08:10 -0800
I have been busy try to work with different types Kamal but was not satisfied.
1. The “indexcard Kamal” held on arm length, the distance from the eye varied
depending how stiff my armmuscles where from 71 to 73 cm, so not very consistent.
2. The Kamal held on constant distance with a tape measure, needed two hands and did not feel good.
Well perhaps for a real emergency, I always have a small teap measure in my pocket.
3. The Kamal held on constant distance with a dowel, I nearly poked my eye out, so not usefull.
4. The compleet paper Kamal with a paper distance holder, looks flimsy to me and two handend.
5. The “original” Kamal with a string and knots between your teeth, did not like to bite the whole
time on a string. Also not very hygienic.
Well then forget the Kamal?
I found in a drawer a loop that was deliverd years ago with the first USB stick I bought.
You can then hold the USB stick around your neck.
Well I thought when I put the loop around my head and connect it to the Kamal I need only one
hand for the Kamal. But the loop was a lot to short and made off material that streched.
I worked out the idea further, I took a standard 150mm alu. Steadler Ruler.
On the top in the middle I cutted one U shape with the bottem on the 0mm mark
I can then put the celestial object on the bottem off the U and read the ruler at the horizon.
I liked the idea of Greg R. for filtering the Sun, but for starsights the filter was not needed.
So i needed a collapsible filter, I had a piece Ø 73mm and 3mm thick black Perpspex.
Black Perspex blocks all lightrays below ~750nM, Infrared is ~850nM, so if you look to the Sun
you see a red Sun through the black Perspex. I disovered this in 1998 when I darkend the portlights
in the Vbed of my boat. In the afternoon when the sun pooked through the portlight I saw the sun
and shadows off the pontoon. Perhaps also usable for a replacement sextantshade.
For lighter conditions I added a green plastic torchwelding glass cutted with a siscor. I cutted a piece
off the shades so when not in use, the scale of the ruler was free to look at the horizon. Drilled 3mm
holes in the shades and the ruler and mounted them with separation washers and a 3mm bolt.
I bought at a DIY store 2 mtr ballchain with two end connectors. Used one connector for adjusting
the lenght of the chain. Drilled in the middle of the ruler a 3mm hole for the end connectors and bolt.
The trick is to lay the ballchain around your head on your ears, and pull the chain tight.
I use my left hand and use my right (dominant) eye. I checked a few times the distance from my cheekbone
it is fairly constant at the desired ~565mm.
This is from the ratio 1cm on the kamal at 571mm distance equals 1°.
And from George Huxtables advice to take 6mm off for the center off your eye 571-6=565mm.
The balls are on a distance off 4,4mm, so the Kamal distance can be changed in 2,2mm steps.
There are also ball chains with 2mm balls, but I could not find the desired length and endfittings.
So far the construction of the “OTHER” Kamal. If it works in practice? I yet do not know because
I am in the mountains and for more then a week we can see only clouds and fog. (see photo).
There is also no horizon for reference.
The only problem until now, is that the right halve of the ballchain blocks the sight on the 7cm mark.
Thats because the top ballchain to my right ear is at eye level. Well every construction has its drawback.
Perhaps I have to copy the scale around the 7cm mark on the left side of the ruler.
Or switch the chains, top chain to the left ear, then the 8,2mm mark is blocked.
I hope I can use this Kamal without the other problems that the different Kamals had for me.
I have to wait for better weather conditions for testing.
Have a nice Christmas.