Solar corona

The corona during the total solar eclipse on July 11th, 1991 was of the structure typical for solar cycle maximum.

Date11. 07. 1991
Time2nd contact 18:47:52 UT, 3rd contact 18:54:23 UT
Total eclipse duration: 6 min 30 sec
PlaceLa Paz, Baja California, Mexico
Coordinate110.22° W, 24.08°N
ConditionsExcellent, clear sky, altitude of the Sun above the horizon: 82°
OpticsNikon 300 mm with Nikon 2× teleconverter
CameraNikon FM
FilmKodachrome 64 (10 images), Kodachrome 200 (9 images)
Exposure1/125 s - 1 s (Kodachrome 64), 1/1000 s - 1/4 s (Kodachrome 200)
ProcessingComposition of 19 images. Images were aligned by means of phase correlation technique and then processed using Corona 3.0 software. Final processing was done by means of ACC 6.0 image analyzer.
Image processing by Hana Druckmüllerová and Miloslav Druckmüller
ScannerNikon Super Coolscan 4000 ED (4000 dpi resolution, RGB, 3× 16 bit/pixel, 16× multisample)
SoftwarePhaseCorr 3.0, FICclr 1.0, Corona 3.0, Sofo ACC 6.0 with Match II Module
NoteThe graph above the table shows the average values of the relative number of sunspots in which the red arrow indicates the time of 1991 eclipse. Graph was created according to data from Sunspot Index Data Center, Brussels.
OrientationThe image has the standard orientation (N top, E left)
Copyright©1991 William L Reyna Jr, ©2005 Hana Druckmüllerová, Miloslav Druckmüller


Miloslav Druckmüller
Institute of Mathematics, Faculty of Mechanical Engineering
Brno University of Technology, Czech Republic
Page last update: 1.5.2007