24 September 2012 Image quality tests on the Canarias InfraRed Camera Experiment (CIRCE)
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In this paper we present the results of image quality tests performed on the optical system of the Canarias InfraRed Camera Experiment (CIRCE), a visitor-class near-IR imager, spectrograph, and polarimeter for the 10.4 meter Gran Telescopio Canarias (GTC). The CIRCE optical system is comprised of eight gold-coated aluminum alloy 6061 mirrors. We present surface roughness analysis of each individual component as well as optical quality of the whole system. We found all individual mirror surface roughness are within specifications except Fold mirrors 1 and 2. We plan to have these components re-cut and re-coated. We used a flat 0.2-arcseconds pinhole mask placed in the focal plane of the telescope to perform the optical quality tests of the system. The pinhole mask covers the entire field of view of the instrument. The resulting image quality allows seeing-limited performance down to seeing of 0.3 arcseconds FWHM. We also observed that our optical system produces a negative field curvature, which compensates the field curvature of the Ritchey-Chretien GTC design once the instrument is on the telescope.
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Nestor M. Lasso Cabrera, Nestor M. Lasso Cabrera, Stephen S. Eikenberry, Stephen S. Eikenberry, Alan Garner, Alan Garner, S. Nicholas Raines, S. Nicholas Raines, Miguel V. Charcos-Llorens, Miguel V. Charcos-Llorens, Michelle L. Edwards, Michelle L. Edwards, Antonio Marin-Franch, Antonio Marin-Franch, } "Image quality tests on the Canarias InfraRed Camera Experiment (CIRCE)", Proc. SPIE 8446, Ground-based and Airborne Instrumentation for Astronomy IV, 84462M (24 September 2012); doi: 10.1117/12.924840; https://doi.org/10.1117/12.924840


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