Photochromic focal plane masks for MOS spectroscopy

摘要

The development of smart devices based on new materials is a possible strategy for renew small telescopes which nowadays are loosing appeal. In this scenario, we propose a FPM (Focal Plane Mask) based on photochromic materials for MOS spectroscopy. Photochromic MOS masks consist of polymer thin films which can be reversibly made opaque or transparent in a restricted wavelength range using alternatively UV and visible light. Slit patterns can thus be easily written by means of a red laser directly at the telescope place, making possible to optimize their dimensions to the observing conditions and also any kind of shape can be obtained, included curved geometry, without mechanical limitations. To test the technique we designed and produced two different photochromic masks, which were successfully used at the national Copernico telescope in Asiago (Italy).