| Type |
Conference Paper |
| Names |
Lisa Crause, Matthew Bershady, David Buckley, Ian S. McLean, Mark M. Casali |
| Proceedings Title |
Proceedings of the SPIE |
| Conference Name |
Ground-based and Airborne Instrumentation for Astronomy II |
| Volume |
7014 |
| Pages |
210 |
| Series |
Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series |
| Date |
August 1, 2008 |
| URL |
http://adsabs.harvard.edu/abs/2008SPIE.7014E.210C |
| Library Catalog |
NASA ADS |
| Abstract |
A differential method was used to investigate the focal ratio
degradation (FRD) exhibited by, and throughput of, a selection of
current-generation optical fibres. These fibres were tested to establish
which would be best suited to feed the High Resolution Spectrograph
being built for the Southern African Large Telescope (SALT), as well as
for future instruments on WIYN and SALT. The double re-imaging system of
Bershady et al. (2004) was substantially modified to improve image
quality and measurement efficiency, and to permit a direct
FRD-measurement in the far-field. The re-imaging method compares the
beam profile produced by light which passes through a fibre to that
which does not. Broad and intermediate band-pass filters were used
between 400-800 nm to test for wavelength dependence in the observed FRD
over a wide range in beam-speeds. Our results continue to be at odds
with a mico-bend model for FRD. We conclude that the new Polymicro FBP
fibre is the most suitable product for broadband applications. |