title: Tunable liquid-crystal filter for solar imaging at the He i 1083-nm line.
abstract: A Lyot-Ohman filter for imaging near the solar He i 1083-nm line is described. Fast and continuous spectral tunability is provided by nematic liquid crystals. This solid-state filter has a free spectral range of 2.35 nm and a spectral resolution of 0.135 nm at the operating wavelength of 1083 nm. A wide-fielded design was used for both static and electro-optic retarder elements, facilitating use in fast imaging systems. A first-light He i image of the Sun is presented.
authors.forename: G A
authors.initials: GA
authors.lastname: Kopp
authors.forename: M J
authors.initials: MJ
authors.lastname: Derks
authors.forename: D F
authors.initials: DF
authors.lastname: Elmore
authors.forename: D M
authors.initials: DM
authors.lastname: Hassler
authors.forename: J C
authors.initials: JC
authors.lastname: Woods
authors.forename: J L
authors.initials: JL
authors.lastname: Streete
authors.forename: J G
authors.initials: JG
authors.lastname: Blankner