Chromospheric observations in the helium 1083NM line : a new instrument

Photometric, spectroscopic and polarimetric observations in the Helium 1083 nm line provide important diagnostic information on the structure and dynamics of the chromosphere. We describe an imaging instrument designed to probe the chromosphere in the Helium 1083nm line, based on a Helium magneto-optical filter. The instrument has two narrow passbands ((almost equal to) 0.006 nm) in the wings of each line of the Helium 1083nm triplet, high throughput and stability, making it ideal for making high cadence observations in support of studies of chromospheric dynamics and wave propagation. We describe the characteristics of the instrument and present preliminary observations and discuss future plans.