Norikura Observatory 10cm Coronagraph

The 10cm-aperture coronagraph was built in 1950. Coronal green-line (5303 Angstrom) emission has been observed continuously since then, by trained observers using a direct-vision spectroscope. Photographic observations of green line coronal loops, H-alpha prominences and so on are made from time to time. The number of observing days per year is roughly 100, and the data are reported in IAU Quarterly Bulletin on Solar Activity.
From 1997 to 1998 a major improvement in the optical system was made. In our new system (NOGIS; Norikura Green-line Imaging System), a 5303 Angstrom Lyot filter can provide two-dimensional maps of green line intensities and Doppler shifts. together with a cooled CCD camera, very high sensitivity observations of the solar corona are now possible. (In Japanese, nogis means this instrument.)

List of Papers

Comet Ikeya-Seki (October 1965) observed by the 10cm coronagraph