Please note this project uses potentially dangerous/life threatening 240V mains electricity supply – please ensure you are qualified to work with this or ask someone with such qualifications to do this work for you.
The following is a description of what I did rather than a recommendation for how this should be done.
My modifications required began with my removing the neon bulb from its RELCO flourescent light starter casing and attaching 2 x 47 Kiloohm resistors in parallel to one limb of the neon bulb. The bulb is then simply connecting to 240V supply. Once I confirmed this worked, I connected a delay switch unit – this automatically switches the light off after 20 mins to preserve the life of the bulb as the neon bulbs in these starters have a life expectancy of only 90 hours each.
The delay switch unit is the box with printed circuit in the last photo – I did not make this but bought it off eBay.
I now need to mount the bulb in a housing so it can be safely used outside for calibrating my spectrometers at the telescope.
The photos below refer to the above process.
There is a follow up post available to the above which describes the completion of this project:
And the following one shows the first calibration spectra taken with the new calibration light: