Survivalism & Self Sufficiency Topics > Primitive Skills & Earth Skills

Sundials and their application to Prepping

<< < (3/5) > >>

Carl:
Karma Liberty, I like that

bcksknr:
     I found an interesting sundial at a large flea market. It is actually a "noon gun". On a dinner plate sized round base is a standard inscribed arc with the hours. There is a standard 'Gnomen" to cast the suns shadow and show the hours. However, there is also a six inch brass cannon mounted on the base, with a magnifying glass mounted above it. When properly oriented, precisely at noon, the magnifying lens focuses on the cannon's touchhole. I've loaded it with a small blackpowder charge and a wad of tissue. At noon (local time) it goes off with a loud report. Fun, but something I'd rather not leave loaded outside, except to demonstrate. Of course, pretty useless if it rains or is cloudy.

Carl:

--- Quote from: bcksknr on June 10, 2017, 07:02:40 PM ---     I found an interesting sundial at a large flea market. It is actually a "noon gun". On a dinner plate sized round base is a standard inscribed arc with the hours. There is a standard 'Gnomen" to cast the suns shadow and show the hours. However, there is also a six inch brass cannon mounted on the base, with a magnifying glass mounted above it. When properly oriented, precisely at noon, the magnifying lens focuses on the cannon's touchhole. I've loaded it with a small blackpowder charge and a wad of tissue. At noon (local time) it goes off with a loud report. Fun, but something I'd rather not leave loaded outside, except to demonstrate. Of course, pretty useless if it rains or is cloudy.

--- End quote ---


Cool,and very rare ,if origional...an alarm clock.

bcksknr:
     While we probably don't have to worry about being late for an appointment after the SHTF, modern folks are so driven by time that if the grid goes down or an EMP fries the digital watches, the ability to even roughly know the time could help ease a least a little of the stress.
     I have a couple of sundials, one is combined with a compass and is a repro. of one found at a Rodger's Rangers barracks.  I also have a mantle clock that keeps very good time and a variety of heirloom pocket watches. I even have one of those "cheap" Scotty pocket watches. Each of my kits has at least one way to tell time. Then there is always the "stick and shadow" method. If it all goes down the toilet, I think it's important to have familiar things to keep as much of a sense of normalcy as possible. It's relatively easy to make a compact sundial that would fit in a match box, coupled with your compass it becomes a "clock". I also have the magnetized needles removed from some cheap compasses, tucked in my wallet and other places. They are light enough to float on a palm full of water. Of course with the right knowledge, you can find north and construct a sun clock with just whats under your feet. 

iam4liberty:
Just getting back to this.

3. Horizontal and Vertical Sundials

Once people started regularly using shadow lengths to judge time they noted an interesting fact, the shortest shadow of the day always pointed due North (in the Northern hemisphere).  This was very useful for navigation purposes.  But when combined with another observation it led to an even better way to measure time. 

By this time people were used to measuring time at night by watching the stars circle the northern star.  This star is now Polaris but back then (around 3000 BC) this was the star Thuban.  Watch this video for example of how stars move around the polar star: https://youtu.be/SYcKaBzr87g  As noted in this video this is because the earth rotates and the polar stars reside 'above' the earth's North pole.

So it was only natural to look at the apparent rotation of the shadow around the shadow stick as a basis of time, especially since there seemed to be some connection between the shadow length and the polar stars.  Some cultures even stated that the sun 'bowed in homage' to the polar star.

With sticks pointed directly straight up (i.e. perpendicular to level ground) this was not very successful.  The rate at which the shadows moved around the stick did not do so at an even pace.  Furthermore this varied by location and time of year.  But an almost magical thing happened when the stick was pointed at the polar star; the rotation became very stable!  This video shows visually why this happens: https://www.youtube.com/watch?v=0coseLMOGhA

This resulted in an amazing invention, the horizontal sundial.  By angling the gnomon (stick) of the sundial a more consistent time measurement could be set.  This allowed greater coordination of work across a region.  A community sundial could be set in a marketplace to set time of trade, courts for disputes, religious services, fishing/shipping schedules, etc.  Then homesteads surrounding that area could have their own sundials and coordinate accordingly.  This was very important as city centers became more defensible (e.g. walled) and ingress/egress was limited to specific times. In many ways sundials created the sense of 'community' common around population centers.  Almost every ancient society deployed this technology:

Viking


Greek


Egyptian




By medieval times the same technology was incorporated in a vertical form and even integrated in the key buildings.  The amount of detail which went into them show just how important they were.

Ireland (7th Century AD)


Chantres Cathedral (~1150 AD)


Konark Temple (~1250 AD)


Even today these monumental sundials are still used daily as shown in this video: https://www.youtube.com/watch?v=K9RF9lLBIMs

In modern times the sundial is used as a rallying point to give a sense of "community" such as the recently constructed Perranporth Sundial in Cornwall.

https://www.bordersundials.co.uk/perranporth-sundial-cornwall/

Navigation

[0] Message Index

[#] Next page

[*] Previous page

Go to full version