The Instructables website is having an Optics Contest (going for 43 days from now). You could win an iPhone X! These are DIY projects that you write up with pictures so that other people can replicate them. Instructions --> Instructables. There are already several entries you can view there including: making a laser cnc machine how to measure the wavelength of laser light (from laser pointers) how to recollimate binoculars The last one I had an interesting method, but it was too late for my purposes (my wife just got some decent binoculars which I noticed were out of alignment, so she then threw them out). If anyone makes any entries, it would be interesting to see a link to them here.