The total solar eclipse of 1991 July 11, was photographed from Mauna Loa, Hawaii, by a research team from the High Altitude Observatory of the National Center for Atmospheric Research, Boulder, Colorado and Rhodes College, Memphis, Tennesee. NCAR is sponsored by the National Science Foundation.
The photograph of the solar corona was taken with a camera system developed by Gordon A. Newkirk, Jr. This specialized instrument photographs the corona in red light, 6500 A -- through a radially graded filter that suppresses the bright inner corona in order to show the much fainter streamers of the outer corona in the same photograph.
In using this image, you must credit:
Technical Information for image: WLCC91
Time: 17:31:11 UT
Pangle: 1.60 degrees Heliocentric north is 1.6 degrees counter
clockwise of vertical. Vertical (top) is
geocentric north. Left, (9 o'clock) is east.
To assist in orientation, the darkest region is to
the NORTH (top). There is a bright "hook" prominence
in the NORTHWEST (upper right) and a barely visible
prominence in the SOUTHWEST (lower right). There
are several dots of prominences just slightly
SOUTH of EAST (left, and just a little down).
Objective aperture 11.4 cm
Focal length 178 cm
Focal ratio f/15
Film Kodak Technical Pan / 2415
Development D19 - 5 minutes (Film was developed at Sacramento Peak
Observatory by Lou Gilliam)
Wavelength isolation filer - Schott OG-3
Effective wavelength - 6500 A
Exposure 27 seconds
Radial filter range - 10^4 in transmission.
Note: There are round dark circular artifacts in the image. These are
the result of out of focus dust within the telescope.
