spase://SMWG/Instrument/KittPeak/Magnetograph

This archive contains daily full-disk solar observations
made with the NSO/KP solar magnetograph (Applied Optics, Vol. 15, 40). An image of the sun is
focused by the NSO/KP vacuum telescope on the slit of a Littrow
spectrograph. The slit covers 0.7 arc seconds by about 550 arc seconds.
A pair of self-scanning 512-element integrated diode arrays are employed as
detectors at the final focal plane of the spectrograph. The spectrograph is
arranged to produce a spectrum centered on one of these lines: 868.8 nm
FeI, 1038 nm HeI, or 550.7 nm FeI. For the FeI lines a Kerr cell is used
as the electrooptic light modulator. It passes alternately left or right
circularly polarized light to allow longitudinal Zeeman splitting of the
spectrum line to be observed. The data are processed in real time to
produce data quantities along the slit using selected wavelength windows
that span the spectrum line. By controlling the pointing of the telescope,
a full-disk image can be built up from four swaths in about 40 minutes.
The scans start in the northwest and end in the southeast. The image
orientation is heliocentric with north at the top and east to the left.
The pixel size is nominally 1 arc second.
ftp://nsokp.nso.edu/512_cdrom/README