In 2020, NPF researchers presented several articles at the prestigious SPIE conference series, resulting in three publications in the proceedings of the “SPIE Astronomical Telescopes + Instrumentation 2020” section.
SPIE is a worldwide conference on astronomical instrumentation -including telescopes- held every two years and in 2020, due to the spread of the coronavirus in the world, it was held virtually for the first time.
Amelia Bayo, director of the Millennium Nucleus of Planetary Formation; Nicolás Soto and Sebastián Castillo, engineers of the center, presented, in a talk and two posters, the progress that the project has had since it began with the manufacture of mirrors based on carbon fiber. This, focusing on the materials used, the method to build the base of the mirror itself, and the way in which the group measures all this process in an iterative way and with a precision adaptable to the precision to be reached to be characterized.
The oversubscription factor of these talks is very high, and the contributions led by NPF researchers shared time on the program with GMT, EELT and TMT, and current instruments such as GRAVITY.
Sebastian Castillo’s publication focuses on how the arrangement of fibers within the composite material can totally alter the final results. This study shows that even small differences in the direction of the fibers can lead to different results.
Castillo is currently conducting additional tests to ensure the reproducibility of the results, systematically developing replicates with identical curing methods and conditions but varying the orientation in which the sheets containing the carbon fibers are placed, to determine if there is a difference in the surface quality. “This experiment was designed to find methods to look for methods to counteract a problem known as fiber print through, in which the surface can be influenced by the inner layers, affecting the final optical quality of the part”, explains the engineer.
On the other hand, Amelia Bayo’s publication summarizes for the first time the whole process that the NPF, in collaboration with the Scientific and Technological Center of Valparaiso (CCTVal), has developed in the project to systematically generate good quality carbon fiber mirrors. “In the publication, the whole process is described in broad strokes, from how the composite material is stored stored similarly to tissue fabric at low temperatures to the coating with aluminum of the resistant, high quality surface of a carbon-fiber mirror of about a mirror based on carbon fiber of about 20cms in diameter,” says the astrophysicist.
Finally, in his publication Nicolás Soto focuses on the systematization of the quality control and measurement systems involved in the whole process. The main challenge lies in the fact that magnitudes of the order order of millimeters to microns, or even nanometers, sizes absolutely imperceptible to the human eye, must be measured. Most of the measurement methods are well known, but far from trivial to calibrate or apply, and this publication describes the entire process and points out novel techniques for measuring convex surfaces, i.e., those that do not generate real images.
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