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Tea Candle at 250nm

Dr Klaus Schmitt

Well-known member
A simple try to record videos at 250nm UV-C using an amplified MCP camera setup.
There are rather interesting Nitrogen lines being emitted in UV-C and UV-B especially
on the hot zone at the outside and top of that candle flame, where the gases get oxidized
with the Oxygen of the surrounding air, whereas the inside appears rather dark.

[MCP = Multi Channel Plate; an amplified system with UV sensitive entrance plate
down to 190nm. amplifies 20-50.000x (adjustable) and has an green phosphor screen
which I made a relay lens for that allows to project that image to a camera sensor.]

VIDEO IS HERE: Candle at 250nm

Candle 250nm Screenshot 2020-10-23 120837.jpg
Last edited:

Asher Kelman

OPF Owner/Editor-in-Chief

What a beautiful representation!

Fascinating as spicules of UV activity penetrate out in transient fingers, as if licking the air!

I thought it would be nice to embed the wonderful video 4 U!

On a chemistry level, what is the reaction that releases this UV light and why is it so thin a zone compared to the outer yellow sodium wavelengths, or the combustion of soot from incomplete oxidation of methane, which of course are not being recorded?


Dr Klaus Schmitt

Well-known member
Thanks, how did you embed that? Haven't found that function...

Here is a nice paper about that: https://www.researchgate.net/public...twork_Node_for_Ultraviolet_Detection_of_Flame

Actually I usually use my 311nm filter for that, will do that and see the differences. It was more a test how deep into UV-C I can see with that MCP...

I have done similar before with a gas flame and several filters...

Double hexaptych (top to bottom) of Visual light; emitted UV 320-390nm, 310-350nm, 290-340nm, 280-315nm, 304-322nm. Right side is morphological gradient filtering of left side:


Dr Klaus Schmitt

Well-known member
I wonder whether there are flies that flash light in the UV spectrum!


You mean like fireflies when they mate? Could be, but never heard about it. It is not very economic I guess as the shorter the wavelength, the higher the needed energy to henerate those UV photons and they also reach not as far due to absorption in air compared to green or red flashes....