Liquid Crystal Tunable Filters are optical devices electronically controlled to alter their passband on demand without involving mechanics. By incorporating such a device into an imaging system, a datacube can be constructed by capturing images while stepping the filter through a series of wavelengths.
In astronomy, continuing improvements in the sensitivity of telescopes and detectors have increased the number of objects available for study far beyond the capabilities of conventional spectroscopic systems to measure them. Instead of collecting spectra a single object at a time, research into multi-object spectroscopy solutions, the ability to examine many objects simultaneously, is the current focus in the field. This work tests the concept that an LCTF system could be of significant practical value to multi-object spectroscopy in astronomy.
Presented is a detailed description of the assembled system; the reduction, calibration, and validation of the collected data; and the use of this data, collected by an LCTF system, in an important pragmatic example, the automated classification of stellar objects from the open cluster Berkeley 87. As a result of this experiment, the magnitudes of 26 stars for which no such data previously existed have been measured via the LCTF. Classifications derived from the LCTF data are presented for 74 stars from the cluster, where only 16 existed in previously published works. Four of these 16 were used for calibration, while the remaining 12 served to demonstrate process validation. Thus, some 58 stars with no previously published classification were classified, demonstrating that an LCTF-based system holds promise for astronomical multi-object spectroscopy.
Library of Congress Subject Headings
Astronomical spectroscopy; Liquid crystal devices
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
McInnis, David A., "Astronomical multi-object spectroscopy with a liquid crystal turnable filter" (2006). Thesis. Rochester Institute of Technology. Accessed from
RIT – Main Campus