Double-Fourier spatio-spectral decoding

Peter Tuthill*, Theo Ten Brummelaar, Michael Ireland, Stephen Ridgway, Hal McAlister, Nils Turner

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contributionpeer-review

1 Citation (Scopus)


Observational modes in which simultaneous high spatial and spectral information are recovered, without the complexity and expense of a dispersed detection system, have been discussed for some time. Sometimes called Double Fourier/Spatio-Spectral Interferometry (DFSSI), these methods fuse the concepts of Fourier Transform Spectrometry with high spatial resolution interferometry. The basic underlying principle comes from the idea that different spectral components, yielding different fringe frequencies, can be separated out in the fringe spectrum for individual study. However in practice, seeing fluctuations have the effect of shifting and blurring together the fringe frequencies making it difficult to isolate discrete spectral components. DFSSI has not been widely exploited in astronomical interferometry, due in part to such considerations. Here we propose a closely-related, although distinct technique which is the analog of DFSSI implemented in the spatial (delay) space rather than the time (frequency) domain. We propose the name Double-Fourier Spatio-Spectral Decoding to distinguish it from the latter. The technique relies on careful calibration of the fringe envelope shape, which is a function of the shape of the overall bandpass of the interferometer. We show that for astrophysical systems with interesting variations in spatial structure for neighboring spectral regions (such as stars with emission-line winds) that it is possible to untangle separate spatial and spectral components without a multi-channel dispersed fringe detector. The principle has been demonstrated successfully with observations of the prototype emission-line object P Cygni at the CHARA array.

Original languageEnglish
Title of host publicationAdvances in Stellar Interferometry
Place of PublicationWashington, DC
Number of pages9
Volume6268 I
ISBN (Print)0819463337, 9780819463333
Publication statusPublished - 2006
Externally publishedYes
EventAdvances in Stellar Interferometry - Orlando, FL, United States
Duration: 25 May 200630 May 2006


OtherAdvances in Stellar Interferometry
Country/TerritoryUnited States
CityOrlando, FL


  • Optical Interferometry


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