Correct exposure times for recording spectral lines

Physikfan, Tue Feb 06 2018, 11:20AM

Correct exposure times for recording spectral lines
The spectra are Hg spectra, photographed from a Canon 10D, with increasing exposure times from top to bottom, (1/90 s, 1/30 s, 1/10 s, 1/2 s, 3 s), light source is a Hg high pressure lamp , the entrance slit is imaged on a screen with a quartz lens via a reflection grating, the left part consists of an ultraviolet luminescent screen to detect the UV lines:

0011sg
033sg
1sg
5gs
IMG 95811000x2473s

In the last two spectra, the overexposure of the 546nm and 577nm lines is already clearly visible.

Further experiments with quartz prism are in preparation.
Re: Correct exposure times for recording spectral lines
2Spoons, Wed Feb 07 2018, 01:25AM

The relative magnitude of the UV portion may not be correct if you are using a luminous pigment to down-convert to visible, as the quantum efficiency probably varies with wavelength.
Re: Correct exposure times for recording spectral lines
Physikfan, Wed Feb 07 2018, 11:55AM

Hi 2Spoons

"The relative magnitude of the UV portion may not be correct if you are using a luminous pigment to down-convert to visible, as the quantum efficiency probably varies with wavelength."

I agree completely with your statement.
But up to now I have only the possibility to detect UV-lines by recording pictures from a fluorescent screen.
There exists an UV-Nikkor for exorbitant money but I am not sure if the the UV light through this lens could be detected accordingly by a very special Nikon camera body.

Regards

Physikfan