Hi Robin,
Many thanks for your concern and experienced viewpoints. much appreciated !
To clarify something first: With ” incident light intensity” I did not ment throughput. It concerns the light bundle falling in on the grating of the spectrograph coming directly from the slit. Hence: Intensity depends on the energy and is proportional to the square of the Amplitude, which is sinusoidal and proportional to the slit width. Two effects are multiplicated here : increasing slit width increases the spatial fraction or area of the light bundle and besides that the spectral fraction. It is a common way to express the theoretical behaviour in analytical spectroscopy like absorption/emission/fluorescence type.
Throughput is the final result of the “Spectrograph train” and is proportional to the Bandpass/slit width.
Excellent Idea to compare the two set ups. I already used the CAOS calculator to see the preliminary difference, thanks Robin.
Anyway I’m certainly interested in the “set up result” comparison with Jack. As soon as he has uploaded his spectrum to the database we will start comparing fluxes. Also the excellent work input from Ernst, who always gives an evaluation of the recorded spectrum is very valuable. Last evaluation indicated a perfect and reliable match of the EW for the V and the R component on the baseline so far, so this is excellent news for this short exposure. We’ll see how it evolves…
Photometric slit recording tests are already foreseen, I hope Jack has also such a slit, so we can compare those also. Very interesting and scientifically important experiments.
Have a nice day,
Kind regards,
Marc.