Engineering
Invisible Writing
Herbert O Yardley was a a code clerk in the US State Department who took an interest in codes and ciphers. He taught himself as much as he could and he proposed a cryptographic bureau. [more…]
Physics
Engineering
Making A Ruby Laser – Part Three
More information on laser speckle can be found here: Speckle pattern A Mirror Alignment Tool The most important part of constructing a ruby laser (or any laser with external mirrors) are getting the mirrors alligned [more…]
Engineering
Making A Ruby Laser – Part Two
(a ruby rod lit by two bright blue LEDs. Due to the IR filter in my camera the pink colour is actually red. What you are seeing is the absorption of the blue light and the [more…]
Engineering
Making A Ruby Laser
Introduction For many years the Doc has had the desire to attempt the construction of a ruby laser. After six months of hard work, disappointment, late nights, lots of booze and a drained bank account [more…]
Engineering
English Cameras & their Lenses (ii)
Subtly different from the two ‘iconic’ German cameras in my part i, are these two English equivalents from the 1950s: the Reid, arguably a better-than-copy of the post-war Leica, and the Microflex of 1960 – [more…]
Engineering
English Cameras & their Lenses
If you ask many people, who, they think, were the most innovative, ‘cutting-edge’ in cameras and lenses, the answer would probably be either, ‘The Germans’ or, possibly, ‘The Japanese’; ask them who made the lenses [more…]
Mathematics
Are We living in a Simulated Universe?
Firstly to have any understanding of this theory, one must admit the possibility of our universe existing within a Multiverse. “A multiverse (or meta-universe) is the hypothetical set of multiple possible universes (including our universe) [more…]
Physics
The Planets, Our Sun
The picture below gives an idea of the size of our sun, but see later when we compare the size of our sun to other stars. The Prologue: I would like to give a h/t [more…]
Physics
The Planets
A huge hat tip and thank you to EJ of this parish for providing the planetary GIF. Throughout this series, I would like to give a huge H/T to NASA.. I have used other sources as [more…]