Techniques > Variations of Existing Techniques

Sunrise, Sunset and Solar Azimuth

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Skills4Survival:
Lets just say I am becoming very interested in grapes and surrounding science. I am also waiting for temperature to drop and go on a hike, I need it. Since Cascade Designs have understood the necessities in life (I had a straight and hard talk with them) they came up with something which actually makes life better, even when crawling under your shelter.

http://www.cascadedesigns.com/en/platypus/wine-preservation/category

best regards,
Ivo




--- Quote from: Lyle Brotherton on September 19, 2013, 10:26:00 AM ---Thanks Ivo and good to hear from you. Cal says you may have developed an alcohol problem ;)

CP I cannot personally take credit for the origin of this tool, this honour must go to the sadly late Hiroshi Sato, Leader of Special Rescue Teams, Tokyo, Japan, a tremendous SAR expert and terrific personality, sadly missed.

Hiroshi had been a mariner (your clue Adi) and was used to working with sextants and star almanacs.

Hiroshi had invented a sunrise/sunset disc.

It was built out of plywood, around 300mm in diameter, and at the centre had a small hole drilled through which was threaded a length of red nylon line.

Around the circumference of this disc markings had been made at 10° intervals. These were then grouped in segments of three, starting from 10° from the ‘north’. 

Each block of three segments were marked with the consecutive months of the year, starting with October at 10°to 40° followed by November between 40° and 70° and so forth.

He had then separately calculated the suns maximum amplitude in 1° intervals from 5° to 62° latitude; these values were the same for both hemispheres and put the results into a table format.

Using this disc on October 21, 2008 in Tokyo, Japan (Northern Hemisphere) Hiroshi found the Sun’s maximum amplitude at the latitude we were at.

He then scaled the north-south baseline of the disc for the maximum amplitude each side of the centre.

Then he found October 21 on the circumference of the disc and he pulled the red nylon line from the centre of the disc across it.

Holding the line on this date, he pulled its tail toward and perpendicular to the baseline. The intersection on the baseline gave him the sun’s amplitude.

To calculate the Sun setting at the horizon he subtracted the north amplitude from 90° east.

To calculate the Sun setting at the horizon he added the north amplitude to 270° west.   

I made notes about his design and asked if I could try and create a handy tool from his design which he kindly agreed to.

However, when I tried to replicate his results I failed. It was only when a friend, who reads Japanese, informed me that I had put the month names in the wrong place that I got it to work.

My design was to try and continue the handy creditcard sized designs I have for my other tools, as these are easy to carry in your wallet and almost everyone I know takes their wallet onto the hill with them!

I also condensed his table from 1° intervals to 5°

--- End quote ---

Angle of Repose:
Thanks for posting that info Lyle, looks like a good addition to the nav card set.

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