title: Observing the solar corona with a tunable Fabry-Perot filter.
abstract: A solid Fabry-Perot etalon with a 0.16 A passband was used during the 180 s solar eclipse of 2006 for rapid scans of an emission line of the solar corona. The etalon was a Y-cut lithium niobate wafer coated with reflective and conductive (ITO) layers. Voltage applied perpendicular to the etalon face produced a passband shift of 0.0011 A V(-1). During the eclipse, 18 filtergrams were obtained at six 0.22 A steps across the profile of the forbidden [Fe X] spectral emission line at 6374.4 A, which results from the 10(6) K coronal plasma. The 9.3 x 9.3 arcmin field of view showed the structure of the corona above a newly emerged sunspot region. We discuss tests performed on the etalon before and after the eclipse. We also discuss the coronal observations, which show some features with 10 km s(-1) velocities in the line of sight.
authors.affiliation: Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, USA.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Noble
authors.forename: David M
authors.initials: DM
authors.lastname: Rust
authors.forename: Pietro N
authors.initials: PN
authors.lastname: Bernasconi
authors.forename: Jay M
authors.initials: JM
authors.lastname: Pasachoff
authors.forename: Bryce A
authors.initials: BA
authors.lastname: Babcock
authors.forename: Megan A
authors.initials: MA
authors.lastname: Bruck