Brightness isolines

Adaptive filters used to visualize coronal structures (Corona 3.0 software) enable to create images very near to human vision sensation during eclipse but they cause loss of information about absolute image brightness. This information itself is not of big value if the image is only observed on computer screen because the human vision has very poor ability to estimate absolute brightness. This information can be added to the image in the way easily understandable for human vision by constructing of brightness isolines. It makes possible to study the corona shape from the point of brightness distribution.

Date3. 11. 1994
TimeU: 2nd contact 12:50:58 UT, 3rd contact 12:54:50 UT
R: 2nd contact 12:18:17 UT, 3rd contact 12:21:19 UT
PlaceU: Brazil near Chapecó
R: Chile, Putre
CoordinateU: 52° 39' 37'' W, 27° 05' 39'' S, Alt. 725m
R: 69° 33' 33'' W, 18° 11' 22'' S, Alt. 3479m
ConditionsU: Clear sky (Sun 55° above the horizon)
R: High cirrus clouds (Sun 32° above the horizon)
OpticsU: Mertz 100/1875mm
R: Maksutov - Cassegrain MTO 1050/1100mm
Resolution6.69 arc sec / pixel (image on this Web page)
FilmU: Kodak TRI-X Pan, 60×60mm B&W film
R: Kodak Ektachrome Elite 100 (EB), 24×36mm slide film
ProcessingTotally 8 images (4 U,4 R) were used for creation of this image. Images were aligned by means of phase correlation technique and then processed using Corona 3.0 software by means of adaptive kernel convolution. Isolines and final processing were done in ACC 6.0.
Image processing by Miloslav Druckmüller
ScannerU: Nikon Super Coolscan 8000 ED
R: Nikon Super Coolscan 4000 ED
SoftwarePhaseCorr 3.0, Corona 3.0, Sofo ACC 6.0
NoteU ... denotes Úpice observatory expedition
R ... denotes Vojtech Rušin expedition
OrientationThe image must be rotated 21.9° clockwise to achieve the standard orientation i.e. North top, East left
Copyright© 1994 Úpice observatory and Vojtech Rušin © 2007 Miloslav Druckmüller


Miloslav Druckmüller
Institute of Mathematics, Faculty of Mechanical Engineering
Brno University of Technology, Czech Republic
Page last update: 31.3.2007