Can anyone tell me where to find some not too expensive replica diffraction grating? I need it as an aid to locate small planetary nebulae, and perhaps even viewing some of the more prominent spectral features in stellar spectra. It could be useful for educational purposes as well.
Another question: Will it work if I mount the grating in an eyepiece filter, i.e. apply the grating before the light enters the eyepiece? This would be much more convenient than holding the grating between the eyepiece and the eyes.
I would like to experiment with this, trying different arrangements and, if possible, try grating with different grooves per mm values. Suggestions? Advice?
Another question: Will it work if I mount the grating in an eyepiece filter, i.e. apply the grating before the light enters the eyepiece? This would be much more convenient than holding the grating between the eyepiece and the eyes.
I would like to experiment with this, trying different arrangements and, if possible, try grating with different grooves per mm values. Suggestions? Advice?
