I'm an astronomy teacher on a very tight budget. Before I really get into the meat of astronomical information, I want to make sure that my students have some understanding of WHY it is that we know what we do about astronomical bodies, and that means getting them to work with some of the tools and principles that astronomers use, like the light gathering ability of optical components, the dispersion of luminous energy at a distance, basic optical set-ups, and some basic spectroscopy. I've identified quite a bit of equipment that I need in order to do experiments with these topics. This list is: An optics bench (basically a yardstick with clasps to hold lenses/mirrors/screens/etc.) Lenses Mirrors Spectroscopes Spectroscopy gas samples in tubes The electrical apparatus to excite the samples Light sensors and interface equipment (just something to measure the intensity of light for an inverse-square-law basic experiment) Now, last year I had students build their own spectroscopes with peeled cds as a diffraction grating and cardboard tubes. They worked reasonably well. I'm looking for ways that I can provide improvised equipment. Some method of quantitatively measuring the intensity of light to explore the inverse-square law. Some way of either creating my own gas samples or building my own device to excite the gases to the point of luminescence. I feel that the optics bench is probably where I'll get the most bang for my buck, so that's what I've planned to buy so far, but if people disagree, I might reconsider. Educations are at stake! Help me, Physics-Forums Kenobi. You're my only hope.