Recent content by ChrisXenon

OK thanks again Charles.

Thanks BvU. My spectrometer works reasonably well for me with a small amount of it covered, but this is one of several things I now understand much better from this forum, giving me the opportunity to make a better spectrometer. I can't change the lens in my webcam, so this won't be an option...

Thanks Charles, I don't have a mirror and the spectrometer does work. It's giving me spectra bewteen 400 - 1000nm to about 1nm accuracy. But it's wasting the available sensor resolution which is why I wanted to improve it. It's become increasingly clear that I don't really understand how it...

Thanks again Sophie. I've uploaded a diagram. The blue part is the lens barrel and the brown part is the PCB on which the CCD chip and ancilliary electronics are mounted. The camera lens is directly behind the grating - maybe 3mm from it. I don't understand your window analogy - the camera is...

Hello Sophie and thanks for your reply. I've been in the other position - someone is looking for help and is apparently unwilling to invest in a basic Google search or a foirum search or even in writing full sentences to explain a problem they want strangers to solve for them. That's annoying...

Charles, thank you so much. I am new to this so your article is difficult for me to understand but I am working on that. If you're inclined to give more time to me, I'll explain a little more, but if not - thanks anyway. I am trying to improve a simple spectrometer, and my laser pointer setup...

Impressive Merlin. Thank you again.

Thanks

Hutch - you're absolutely right, but there is an IF at the start of your comment. The IF condition fails and with it - your point.

If I direct a laser pointer onto a diffraction grating and place a screen beyond it, I see a diffraction pattern - a line of dots - as expected. If I move the screen further away from the grating, the distance between the dots increases - again as expected. If I place a camera where the screen...

Thanks for making time to reply Kurman. I felt that anyone who knew about diffraction would know about "the triangle". In fact there are very many wrongly-drawn diagram, but figure 6 in http://www.pstcc.edu/departments/natural_behavioral_sciences/Web%20Physics/Chapter037.htm is what I'm talking...

... and yet, miraculously, Merlin understood exactly what I meant. I guess we're telepathically linked... or could it be some defficiency on your part... it's a toughy.

Thanks Merlin! Much appreciated.

So, two wave fronts leave adjacent "slits" in a grating and head for a screem When they get to a point of local maximum, they will have interfered constructively, and so they must be in phase. Therefore the path different will be a whole multiple of the wavelenth. People routinely draw a right...

Excellent - thank you both.