Calibration display for NASA

April 4, 2019

Unbelievable surprise

Our unbelievable story began when we received an e-mail from the NASA. The request from the National Aeronautics and Space Administration was crystal clear – to create a display that would be photographed by high-speed cameras verifying !!!( the reliability of the timing)!!!!. For many years, the NASA had used old digitrons with an accuracy of 0.001 seconds. Our challenge was even greater. To increase the accuracy to 0.0001 seconds.

NASA knew

NASA knew very well who to turn to, because Dalibor Farný was the only one who breathed life back into this technology that had been forgotten for 30 years.

What do you think? Are we able to achieve more with our contemporary digitrons? Of course, you will get the answer to this question here. But let’s take it step by step.

A smile

A smile beyond initial expectations and first complications.
The smile at our original idea of how easy it would be to use what we know, what we are familiar about, only to adjust it a bit for the IRIG timecode, which is used by the NASA for verifying the display accuracy, can never be wiped off our faces.

The implementation of the IRIG output into the display should be a piece of cake, but it turned out to be one of the most challenging elements of the project. We had to ensure that the clock identified the start of each new second on the IRIG timecode to an accuracy of around 1μS.

IRIG timecode

The IRIG timecode is used for transferring timing information from a central time source into a slave equipment such as displays. The implementation of the IRIG required creation of a new, fully analogue part for processing the input IRIG timecode, because our proven electronics arrangement with a digital processor was not fast enough. Despite a few hiccups in development, we still managed to fine-tune this analogue part, so that it has virtually no delays.

Small problems and help from Germany

Another problem was the mutual interference of signals within the electronics. This is why we had to replace a part of PCB with wiring.

During several months, we managed to solve all of the problems. The key person behind the design of the electronics was Mr. Sebastian Melzer, an electro engineer from Germany who was working for us by that time. He played a key role within the whole process.

How we verified the accuracy of the function in the Czech Republic?

We adjusted our bulb setting, and we borrowed a high-speed camera in Prague for testing. The initial setting of the bulb was 100,000 x/s. We went to Prague to verify if the time on the nixie tube Is “moving”, meaning if the numbers are really change and do not shine all at once.

After six months of hard work

We finally finished the display and sent it to the customer to the Kennedy Space Center.


When figuring out what maximum frequency a nixie can reliably switch between digits, we found that we could go up to 100,000 changes per second, so it would be possible to calibrate 100,000 FPS cameras with them. This corresponds with the NASA’s cameras thus we created a display with this highest possible limit.

We still benefit from the findings today

Thanks to these experiences, we have knowledge about possibilities of lightning and extinguishing speed of a nixie tube, which we also use in our other projects, such as the H nixie tube, when animating the lighting.

Still in service. What’s next?

We continue to actively use the second clock with the first one. It makes our testing easier than ever before.
And we have some great news! We have recently received another request for the third display that will also be in the NASA or at its contractor.

24.3.2023 from our headquarters in Březolupy