PRAXIS

a near infrared spectrograph optimised for OH suppression

S. C. Ellis*, S. Bauer, J. Bland-Hawthorn, S. Case, R. Content, T. Fechner, D. Giannone, R. Haynes, E. Hernandez, A. J. Horton, U. Klauser, J. S. Lawrence, S. G. Leon-Saval, E. Lindley, H. G. Löhmannsröben, S. S. Min, N. Pai, M. Roth, K. Shortridge, Nicholas F. Staszak & 3 others Julia Tims, Pascal Xavier, Ross Zhelem

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contribution

5 Citations (Scopus)

Abstract

Atmospheric emission from OH molecules is a long standing problem for near-infrared astronomy. PRAXIS is a unique spectrograph, currently in the build-phase, which is fed by a fibre array that removes the OH background. The OH suppression is achieved with fibre Bragg gratings, which were tested successfully on the GNOSIS instrument. PRAXIS will use the same fibre Bragg gratings as GNOSIS in the first implementation, and new, less expensive and more efficient, multicore fibre Bragg gratings in the second implementation. The OH lines are suppressed by a factor of ∼1000, and the expected increase in the signal-to-noise in the interline regions compared to GNOSIS is a factor of ∼ 9 with the GNOSIS gratings and a factor of ∼ 17 with the new gratings. PRAXIS will enable the full exploitation of OH suppression for the first time, which was not achieved by GNOSIS due to high thermal emission, low spectrograph transmission, and detector noise. PRAXIS will have extremely low thermal emission, through the cooling of all significantly emitting parts, including the fore-optics, the fibre Bragg gratings, a long length of fibre, and a fibre slit, and an optical design that minimises leaks of thermal emission from outside the spectrograph. PRAXIS will achieve low detector noise through the use of a Hawaii-2RG detector, and a high throughput through an efficient VPH based spectrograph. The scientific aims of the instrument are to determine the absolute level of the interline continuum and to enable observations of individual objects via an IFU. PRAXIS will first be installed on the AAT, then later on an 8m class telescope.

Original languageEnglish
Title of host publicationGround-Based and Airborne Instrumentation for Astronomy VI
EditorsChristopher J. Evans, Luc Simard, Hideki Takami
Place of PublicationBellingham, Washington
PublisherSPIE
Pages1-13
Number of pages13
ISBN (Electronic)9781510601963
ISBN (Print)9781510601956
DOIs
Publication statusPublished - 2016
Externally publishedYes
EventGround-Based and Airborne Instrumentation for Astronomy VI - Edinburgh, United Kingdom
Duration: 26 Jun 201630 Jun 2016

Publication series

NameProceedings of SPIE
PublisherSPIE
Volume9908
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Other

OtherGround-Based and Airborne Instrumentation for Astronomy VI
CountryUnited Kingdom
CityEdinburgh
Period26/06/1630/06/16

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Keywords

  • near infrared
  • spectroscopy
  • OH suppression
  • astrophotonics
  • Fibre Bragg Gratings

Cite this

Ellis, S. C., Bauer, S., Bland-Hawthorn, J., Case, S., Content, R., Fechner, T., ... Zhelem, R. (2016). PRAXIS: a near infrared spectrograph optimised for OH suppression. In C. J. Evans, L. Simard, & H. Takami (Eds.), Ground-Based and Airborne Instrumentation for Astronomy VI (pp. 1-13). [99084A] (Proceedings of SPIE; Vol. 9908). Bellingham, Washington: SPIE. https://doi.org/10.1117/12.2232115