| Autor: |
Bland-Hawthorn J, Kos J, Betters CH, De Silva G, O'Byrne J, Patterson R, Leon-Saval SG |
| Jazyk: |
angličtina |
| Zdroj: |
Optics express [Opt Express] 2017 Jul 10; Vol. 25 (14), pp. 15614-15623. |
| DOI: |
10.1364/OE.25.015614 |
| Abstrakt: |
We demonstrate a new approach to calibrating the spectral-spatial response of a wide-field spectrograph using a fibre etalon comb. Conventional wide-field instruments employed on front-line telescopes are mapped with a grid of diffraction-limited holes cut into a focal plane mask. The aberrated grid pattern in the image plane typically reveals n-symmetric (e.g. pincushion) distortion patterns over the field arising from the optical train. This approach is impractical in the presence of a dispersing element because the diffraction-limited spots in the focal plane are imaged as an array of overlapping spectra. Instead, we propose a compact solution that builds on recent developments in fibre-based, Fabry-Perot etalons. We introduce a novel approach to near-field illumination that exploits a 20cm aperture commercial telescope and the propagation of skew rays in a multimode fibre. The mapping of the optical transfer function across the full field is represented accurately (<0.5% rms residual) by an orthonormal set of Chebyshev moments. Thus we are able to reconstruct the full 4K × 4K CCD image of the dispersed output from the optical fibres using this mapping, as we demonstrate. Our method targets one of the largest sources of systematic error in multi-object spectroscopy, i.e. spectral distortion due to instrumental aberrations, and provides a comprehensive solution to their calibration and removal. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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