(Sept 2023)
This Quark was bought in late 2022. It was measured using the following approach:
- Sol'Ex spectrometer in a f/31.4 telecentric beam (TOA 150 f/7.3 => Quark with its 4.3× telecentric => Sol'Ex),
- Sol'Ex spectrometer in a f/31.4 telecentric beam (TOA 150 f/7.3 => Quark with its 4.3× telecentric => Sol'Ex),
| Filter | Test method | f-ratio | Surface measured | FSR | FWHM | Bandwith at 10% peak transmission |
| Quark #3 | Sol'Ex spectro (fc =fi = 200 mm, ASI 462, 0.0471 A/px dispersion) |
f/31.4 telecentric | 10 micron x 4.5 mm | 23.0 A | 0.45 A | 1.3 A (consistent with a FWHM of 0.45 A) |
Sol'Ex spectrometer: measurement in a f/31.4 telecentric beam
Optical setup: Sun => Takahashi TOA 150 => Quark with its 4.3× telecentric beam => Sol'Ex spectrograph
10 microns slit, 200 mm collimating lens, 200 mm imaging lens, ASI 462 camera, 12-bit acquisition.
Measured dispersion = 0.0471 A/pixel
Conditions : blue sky
6 September 2023
Three succesive images :
- Solar spectrum (= no filter).
- Solar spectrum transmitted by the Quark at ambiant temperature (about 30°C). This spectrum is registered to the solar spectrum.
- Same as above, but different vizualisation thresholds for the measurement of the FSR.
- Solar spectrum (= no filter).
- Solar spectrum transmitted by the Quark at ambiant temperature (about 30°C). This spectrum is registered to the solar spectrum.
- Same as above, but different vizualisation thresholds for the measurement of the FSR.
The FSR is equal to 23.0 A
The transmission profile of the etalon is given by the ratio "transmitted solar spectrum/solar spectrum".
The direct measurement on the graph at 50 % and 10% peak transmission are given on the graphs.
Estimation of the FWHM with curve-fitted of the transmisison curve with a Lorentzian function gives a similar value, FWHM = 0.46 A
The bandwidth at 10% transmission is consistent with a FWHM = 1.33/3 = 0.44 A