TY - GEN A1 - Döhring, Thorsten A1 - Rödling, Claudius A1 - Kimmel, Kevin A1 - Zeising, Sebastian A1 - Stadtmüller, Johannes A1 - Stollenwerk, Manfred A1 - Verma, Shruti A1 - Rees, Paul T1 - Optical characterization of reflective coatings for astronomical telescope mirrors T2 - DGaO Jahrestagung N2 - With ground based optical telescopes astronomers observe celestial objects over a wide spectral range. As usually three or even more reflections at telescope mirrors are involved, good reflection properties of the mirror coatings are important. The aluminum evaporation technique has been - and is still - the standard solution for the reflective coatings of large astronomical mirrors. Such coatings have excellent reflectivity in the ultraviolet and in the visible, but perform poorly in the infrared. Silver is the metal having highest reflectivity for wavelengths longward of 400 nm, but isn´t the best choice for reflectivity in the ultraviolet and for blue light. To avoid degradation by oxidation, durable silver coatings need to be protected by transmitting overcoating layers. In the presented study, different metallic coatings – including unusual ones like sputtered iridium - are characterized to identify a coating that is most suitable for the spectral range from ultraviolet to infrared. Experimental results are compared to simulations based on the complex refractive indices of these materials. Thereby dependence of incidence angle and polarization is also considered. N2 - Poster KW - mirror KW - coating KW - iridium KW - astronomy KW - telescope KW - Spiegelteleskop Y1 - 2021 UR - https://dgao.de/jahrestagung/ VL - 2021 SP - 1 EP - 1 ER - TY - CHAP A1 - Döhring, Thorsten A1 - Rödling, Claudius A1 - Kimmel, Kevin A1 - Zeising, Sebastian A1 - Stadtmüller, Johannes A1 - Stollenwerk, Manfred A1 - Verma, Shruti A1 - Rees, Paul T1 - Optical characterization of reflective coatings for astronomical telescope mirrors T2 - DGaO Proceedings N2 - Aluminium evaporation is still the standard solution for reflective coatings of large astronomical mirrors. Silver and gold are also used in specific cases depending on the targeted wavelength. This study characterized different metallic coatings - including unusual ones like sputtered iridium - to identify the most suitable mirror coating for the spectral range from ultraviolet to infrared wavelengths. KW - Iridium KW - mirror KW - coating KW - reflectivity KW - telescope KW - Spiegelteleskop Y1 - 2021 UR - https://www.dgao-proceedings.de/download/122/122_p4.pdf SN - 1614-8436 VL - 2021 IS - 122 SP - 1 EP - 1 PB - DGaO ER - TY - CHAP A1 - Niekamp, Linus A1 - Döhring, Thorsten A1 - Rees, Paul A1 - Hudec, Rene T1 - Technologies, challenges and opportunities for optical CubeSat payloads T2 - DGaO Proceedings N2 - This contribution describes optical payloads of CubeSat nanosatellites and their limiting factors. Some prominent examples are presented, and performance characteristics are discussed in the context of different commercial and scientific applications. Furthermore, the optical payload market has been evaluated and identified suppliers of commercial-of-the-shelf products are listed. KW - CubeSat KW - payload KW - satellite KW - Optik KW - Kleinsatellit Y1 - 2020 UR - https://www.dgao-proceedings.de/download/121/121_p30.pdf SN - 1614-8436 VL - 2020 IS - 2020 SP - 1 EP - 2 PB - Deutsche Gesellschaft für angewandte Optik ER - TY - GEN A1 - Stanik, Eva A1 - Döhring, Thorsten A1 - Rees, Paul A1 - Kroneberger, Monika A1 - Stanik, Martin T1 - Infrared heating for a sustainable powder coating technology N2 - The recent energy crisis revealed the dependence of many manufacturing companies on fossil fuels Industrial processes need to be transformed into sustainable alternatives For powder coatings, which traditionally rely on gas or oil heating systems, infrared radiation can deliver the required process heat The strong dependence of the IR absorption on the geometry of the irradiated parts as well as on the color and sort of the coating powder has to be considered before the implementation of this innovative heating The aim of the NAPUBEST project (German abbreviation for Nachhaltige Pulverbeschichtungs Technologie which means “Sustainable Powder Coating Technology”) is to get a better understanding of these correlations In our laboratory, we realized a prototype of an IR oven for test measurements The high reflectivity of silver coated reflector sheets facilitates the concentration of infrared radiation inside the oven. On the other hand, the absorption of powder coated samples in different paint colors has an impact on the heating efficiency First tests of the equipment and measurements of the angular dependence of the reflectivity of various coated samples are presented. N2 - Poster KW - infrared KW - powder coating KW - sustainability KW - Infrarotheizung KW - Pulverbeschichten Y1 - 2025 UR - https://www.dgao-proceedings.de/abstract/abstract_only.php?id=3156 VL - 2025 SP - 1 EP - 1 PB - DGaO ER - TY - CHAP A1 - Stanik, Eva A1 - Döhring, Thorsten A1 - Rees, Paul A1 - Kroneberger, Monika A1 - Stanik, Martin T1 - Infrared heating for a sustainable powder coating technology T2 - DGaO-Proceedings N2 - Industrial processes need to be transformed into sustainable alternatives. For powder coatings, which traditionally rely on gas or oil heating systems, infrared radiation can deliver the required process heat. The aim of the NAPUBEST project is to evaluate the possibilities of infrared radiation in the powder coating process. In our laboratory, we realized a prototype of an IR oven for test measurements. KW - infrared KW - powder coating KW - sustainability KW - curing Y1 - 2025 UR - https://www.dgao-proceedings.de/download/126/126_p24.pdf SN - 1614-8436 VL - 2025 IS - 126 SP - 1 EP - 2 PB - DGaO ER -