Abstract
MEGARA is the new integral-field and multi-object optical spectrograph for the GTC. For medium and high resolution, the dispersive elements are volume phase holographic gratings, sandwiched between two flat windows and two prisms of high optical precision. The prisms are made of Ohara PBM2Y optical glass. After the prisms polishing process, some stains appeared on the surfaces. For this, in this work is shown the comparative study of five different products (muriatic acid, paint remover, sodium hydroxide, aqua regia and rare earth liquid polish) used for trying to eliminate the stains of the HR MEGARA prisms. It was found that by polishing with the hands the affected area, and using a towel like a kind of pad, and polish during five minutes using rare earth, the stains disappear completely affecting only a 5% the rms of the surface quality. Not so the use of the other products that did not show any apparent result.
Highlights
MEGARA is the acronym of Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía
2.2 High corrosive chemical products Due to the results obtained in the previous test, it was decided to make some tests with products used to remove some kinds of thin films deposited on optical glasses, i.e. to remove the aluminum deposited on optical mirrors
The hand polishing time consuming for surface 2 to get stains vanishing was 5 minutes, the same of the last test. Comparing these results against the results for surface 1, this test the scratch and dig defects did not appear because the caustic soda is not more aggressive than the aqua regia
Summary
This content has been downloaded from IOPscience. Please scroll down to see the full text. Ser. 792 012064 (http://iopscience.iop.org/1742-6596/792/1/012064) View the table of contents for this issue, or go to the journal homepage for more. Download details: IP Address: 147.96.14.16 This content was downloaded on 29/05/2017 at 15:34 Please note that terms and conditions apply. Racine INTERSTELLAR D LINES PHOTOGRAPHED WITH THE OBJECTIVE PRISM P. W. Merrill The FAST Spectrograph for the Tillinghast Telescope Daniel Fabricant, Peter Cheimets, Nelson Caldwell et al Invited: Integrated Optics Amnon Yariv A Detailed Thermal Analysis of the Binospec Spectrograph Warren R. Boyd A NEAR-INFRARED PRISM SPECTROPHOTOPOLARIMETER Hideki Takami, Hisashi Shiba, Shuji Sato et al INTERRELATED OBJECTIVE PRISM AND SLIT SPECTROSCOPY AT CLASSIFICATION DISPERSION C.
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