skip to main content


Title: High-resolution broadband spectroscopy using externally dispersed interferometry at the Hale telescope: Part 1, data analysis and results

High-resolution broadband spectroscopy at near-infrared wavelengths (950 to 2450 nm) has been performed using externally dispersed interferometry (EDI) at the Hale telescope at Mt. Palomar. Observations of stars were performed with the “TEDI” interferometer mounted within the central hole of the 200-in. primary mirror in series with the comounted TripleSpec near-infrared echelle spectrograph. These are the first multidelay EDI demonstrations on starlight, as earlier measurements used a single delay or laboratory sources. We demonstrate very high (10×) resolution boost, from original 2700 to 27,000 with current set of delays (up to 3 cm), well beyond the classical limits enforced by the slit width and detector pixel Nyquist limit. Significantly, the EDI used with multiple delays rather than a single delay as used previously yields an order of magnitude or more improvement in the stability against native spectrograph point spread function (PSF) drifts along the dispersion direction. We observe a dramatic (20×) reduction in sensitivity to PSF shift using our standard processing. A recently realized method of further reducing the PSF shift sensitivity to zero is described theoretically and demonstrated in a simple simulation which produces a 350× times reduction. We demonstrate superb rejection of fixed pattern noise due to badmore » detector pixels—EDI only responds to changes in pixel intensity synchronous to applied dithering. This part 1 describes data analysis, results, and instrument noise. Lastly, a section on theoretical photon limited sensitivity is in a companion paper, part 2.« less
 [1] ;  [2] ;  [2] ;  [2] ;  [3] ;  [4] ;  [5] ;  [2] ;  [2] ;  [2] ;  [6]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Univ. of California, Berkeley, CA (United States)
  3. Boston Univ., Boston, MA (United States)
  4. Middle Tennessee State Univ., Nashville, TN (United States)
  5. Cornell Univ., Ithaca, NY (United States)
  6. Harvard Smithsonian Center for Astrophysics, Cambridge, MA (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 2329-4124
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Astronomical Telescopes, Instruments, and Systems
Additional Journal Information:
Journal Volume: 2; Journal Issue: 2; Journal ID: ISSN 2329-4124
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; 97 MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; dispersed interferometry; Doppler radial velocimetry; high resolution spectroscopy
OSTI Identifier: