Lightweight Mirror Developments

One goal of the Alt-Az Initiative is the development of transportable 1.5 meter class research telescopes. To this end, several Initiative members are developing lightweight, low cost, primary mirrors. Both multiple and single mirror telescope configurations are being considered. Thin meniscus mirrors are being slumped, and approaches for actively correcting these thin mirrors are being investigated. Sandwich mirrors with glass spacers and others with Foamglas cores are under development. Nanocomposite, polyurethane, and glass replica mirrors, which do not require optical grinding or figuring during production, are being evaluated. Finally, spin-cast polymer mirrors are being explored. Although several of these mirror developments are still very experimental, and some may only be useful in optically undemanding applications such as on-axis aperture near IR photometry or low resolution spectroscopy, it is our hope that these efforts will enable the development of transportable, low cost, lightweight, 1.5 meter class telescopes.