spase://SMWG/Instrument/Ground/MaunaLoaSO/CHIP

The Chromospheric Helium-I Imaging Photometer (CHIP)
was installed at MLSO in April 1996. CHIP is a differential device using
properties of the Helium-I line at 1083 nm as an indicator of both
chromospheric and coronal structures. CHIP records images of the sun at
1083 nm, as well as at a number of other nearby wavelengths (for
calibration purposes). It is basically composed of a liquid crystal
variable retarder (tuneable) Lyot filter connected to an IR CCD.
CHIP is unique compared with other Helium-I imagers, in that it obtains
images every 3 minutes, the high cadence crucial to study the rapid
evolution of CMEs. In addition, observations from CHIP should provide
better understanding of coronal holes, coronal arcades, and the
interaction between open and closed magnetic field structures.
Seven line and continuum exposures are recorded within 2 seconds. The
difference of line and one continuum exposures is computed every 3 minutes
to produce one 1083 nm image.
The CHIP FOV is approximately 1.8 solar radii. The CCD pixel size is
2.29 arcseconds and the measured spatial resolution is ~8 arcseconds.
For additional information on the tuneable filter see Kopp et al.
(1996).