Welcome to Stefan Keller-Tuberg's home page

Welcome to my pages of model train, amateur telescope making, scripts to implement a web based photo album, useful shell and perl scripts I've written, patent, Cipher topics.

greenbank radio telescopethe familysteam locomotive
My family and me standing in front of the Greenbank "monster" Telescope in West Virginia and in the garden. The engine waiting at the station is of the Durbin and Greenbrier Valley Railroad situated nearby the Greenbank Telescope.
Click on the images for a larger view (approx 50k bytes each).

A computer controlled model train set

One of my "spare time" activities has been the design and construction of a computer controlled model train set. There are many ways I could have chosen to build it and the articles here tell all about it.

my computer controlled train set

Links to other model train sites

A computer controlled Dobsonian Telescope

OK. So now you've guessed that I have a thing about computer control. At this stage, the telescope is optically working but I've not had the chance to completely finish the software to control it from a computer. However, I'm well into the process and, one day, it will be done.

If you've not heard of a "Dobsonian" Telescope before, here's a picture of mine to give you an idea. A "Dobsonian" Telescope is actually a type of Newtonian telescope.... If this is gobbledegook to you, Just look at the picture.

my 12 inch DOB telescope

The type of Dobsonian shown above is called a truss dob - for obvious reasons. You may also be familiar with another type which is constructed from a solid tube rather than an open truss. These look like small (or large) canons and are certainly much easier to build than the truss type.

However if you built a tube-type Dobsonian as large as this one (and you can build them MUCH larger still), it would be a little hard to drag the telescope out to the back yard or throw it in the back of the car. An assembled tube 2 or more metres long and 45 cm diameter containing mirror and other hardware, together with its mount, would weigh in at 70kg or more. So you would be correct if you guessed that the main advantages of the trusses in a truss dob are to reduce weight and to allow the telescope to be collapsed for easier transport. See my telescope page for more information.

A script kit for a web (html) based photo album.

After several years of ownership of a digital camera, our photos were in a horrible mess. We'd purchased the digital camera to put our box of paper photos behind us, only to discover that we took even more digital photos than paper ones.

Even with a digital camera, you still need to keep your digital photos in order and annotated in order to remember what they were about. More importantly, you also need a convenient way to browse your "digital album". These scripts for Linux and Windows were my solution and once you've managed to install them, they're simple to use.

Useful scripts written in the shell and perl scripting languages.

Includes a script to rip DVDs to your hard drive and compress them, to recursively convert m4a files to mp3, recursively set file and directory permissions, recursively generate m3u playlists.


Over the years, during the course of my work as an engineer, my company has sponsored many patent applications, approaching something like 20 of them in all. Some have issued, some have not. Some of those which have issued have not been maintained and have disappeared from the face of the earth.

One day when looking for other patents, I decided to try to look for some of my own. Surprisingly, I turned up these.

Vigenere Cipher

One day, I set my daughter a challenge to hand decypher a vigenere cypher I created for her. She never quite finished, but she did make good progress. Then I got to wondering how easy it would be to automate the decyphering process. It took me an hour to hack together a pretty foolproof decrypter. Here is the result.

Solitaire Cipher

When all my children were little, one Easter I hid their baskets of eggs at the end of a series of cryptic clues. They enjoyed the hunt so much, they've insisted every year that I prepare a bigger and better hunt for them. Its been a kind of arms race - and the degree of difficulty and sophistication has progressively climbed higher. As I have four children, its quite a deal of work preparing and hiding a series of clues for each of them and hiding their baskets, and this year when I tried to convince them that they were now old enough to stop the 'tradition' (they range in age from 19 to 13), they convinced me yet again to undertake the work.

So for 2013, I settled upon the solitaire cipher.

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