M. Kasper, R. Arsenault, U. Käufl, G. Jakob, S. Leveratto, G. Zins, E. Pantin, P. Duhoux, M. Riquelme, J. Kirchbauer, J. Kolb, P. Pathak, R. Siebenmorgen, C. Soenke, E. Fuenteseca, M. Sterzik, N. Ageorges, S. Gutruf, D. Kampf, A. Reutlinger, O. Absil, C. Delacroix, A. Maire, E. Huby, O. Guyon, P. Klupar, D. Mawet, G. Ruane, M. Karlsson, K. Dohlen, A. Vigan, M. N’diaye, S. Quanz, A. Carlotti
{"title":"NEAR: First Results from the Search for Low-Mass Planets in α Cen","authors":"M. Kasper, R. Arsenault, U. Käufl, G. Jakob, S. Leveratto, G. Zins, E. Pantin, P. Duhoux, M. Riquelme, J. Kirchbauer, J. Kolb, P. Pathak, R. Siebenmorgen, C. Soenke, E. Fuenteseca, M. Sterzik, N. Ageorges, S. Gutruf, D. Kampf, A. Reutlinger, O. Absil, C. Delacroix, A. Maire, E. Huby, O. Guyon, P. Klupar, D. Mawet, G. Ruane, M. Karlsson, K. Dohlen, A. Vigan, M. N’diaye, S. Quanz, A. Carlotti","doi":"10.18727/0722-6691/5163","DOIUrl":null,"url":null,"abstract":"The Messenger 178 – Quarter 4 | 2019 ESO 3.6-metre telescope at La Silla, was modified and used to carry out the acceptance tests of the internal chopper. This was followed by a performance evaluation of the Annular Groove Phase Mask (AGPM) coronagraph with a dedicated optical setup incorporating a line-tunable CO2 laser, elliptical mirrors and germanium lenses. Four AGPM coronagraphs were tested, three specifically optimised for the NEAR filter (10–12.5 μm) and an older sample manufactured in 2012 and optimised for wavelengths between 11 and 13.1 μm. Surprisingly, the older coronagraph performed best, with a rejection ratio of up to 400 at 10.5 μm, and a contrast level of < 10– 4 at 3 λ/D.","PeriodicalId":41738,"journal":{"name":"Jurnal The Messenger","volume":"8 1","pages":"5-9"},"PeriodicalIF":0.3000,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"11","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Jurnal The Messenger","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.18727/0722-6691/5163","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"COMMUNICATION","Score":null,"Total":0}
引用次数: 11
Abstract
The Messenger 178 – Quarter 4 | 2019 ESO 3.6-metre telescope at La Silla, was modified and used to carry out the acceptance tests of the internal chopper. This was followed by a performance evaluation of the Annular Groove Phase Mask (AGPM) coronagraph with a dedicated optical setup incorporating a line-tunable CO2 laser, elliptical mirrors and germanium lenses. Four AGPM coronagraphs were tested, three specifically optimised for the NEAR filter (10–12.5 μm) and an older sample manufactured in 2012 and optimised for wavelengths between 11 and 13.1 μm. Surprisingly, the older coronagraph performed best, with a rejection ratio of up to 400 at 10.5 μm, and a contrast level of < 10– 4 at 3 λ/D.