This paper reports on the use of a tunable, liquid-crystal filter to obtain simultaneous, low-resolution spectrophotometry of multiple stars within a moderately crowded field. The filter is electronically tunable to any wavelength in the range from 400 to 720 nm with a nominal passband of 10 nm FWHM. In order to evaluate the performance of this filter, the central region of the Jewel Box cluster, NGC 4755, was repeatedly imaged as the filter's central wavelength was stepped from 435 to 720 nm in successive exposures. A spectrum for each of five brighter stars in the cluster field was then reconstructed from the stack of images. Diff†erential corrections for each frame were determined by using a standard spectral scan for one of the stars in the field with a known spectral type (the "reference star"). Dereddened spectra of the other stars in the field were then constructed with accuracy only limited by the match between the reference and standard star spectra, and uncertainties in variable reddening across the cluster. This technique allows multiobject spectroscopy to be obtained in potentially very crowded stellar fields using common photometric reduction techniques- namely, PSF fitting.

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Article may also be accessed on publisher's website at: http://www.journals.uchicago.edu/PASP/journal/contents/v111n759.html We thank Barry Logue of Cambridge Research & Instrumentation for information on the LCTF. We also thank the (now closed) University of Toronto Southern Observatory for observing time. An anonymous referee provided a critique that lead to an improved paper. This work was supported by funding for detector development from the NSF S/IUCRC program and the New York State CAT program.ISSN:0004-6280 Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

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Department, Program, or Center

Chester F. Carlson Center for Imaging Science (COS)


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