Mees Solar Observatory Ca II K-line Telescope

Images of the full disk of the Sun in the Ca II K line at 3933 Angstroms are recorded with a CCD camera.

The filter is a Lyot type. The CCD camera has a format of 384 x 576 pixels. The telescope is mounted on the southwest face of the spar, so the CCD rows/columns are at 45 degrees to the Earth cardinal directions

The central part of the CCD is read out, 384 x 400 pixels. The image scale is roughly 5.6 arcsec per pixel. During oscillation observations, multiple exposures are summed to create a single image.

The filter is used in 3 modes:

At 0.3 A bandwidth, tuned to -0.6 A from line center,

to record primarily K1. Only 2 elements of the filter

actually tune, so there are 2 passbands, at +/-0.6A.

This setting is used for observing 5 minute oscillations.

Images are recorded every 30 seconds, and contain 1 to 4

separate exposures.

At 0.3 A bandwidth, tuned to line center to record K3.

This setting is used for observing chromospheric structure.

Only occasional observations are made with this setting.

At 1.2 A passband, used to record K232. This disables the

narrow elements, giving a broad passband at line center.

This setting is used for flare observations. Images are

recorded every 19 seconds and contain a single exposure;

this is speed limit of the system.

Last modified: Fri May 24 17:24:00 HST 1996