Although this was expected, I must deplore the failure of many totality observations, due to the bad weather (mainly in Western Europe and India, although observers in Romania and even Iran had to cope with clouds) and for some, to manipulation errors. However, with such a dense network (25 stations), you have the assurance of a significant return, in terms of scientifically valuable images. For instance, we got excellent data from the Belgian team of the Royal Observatory of Belgium (ROB) which was observing from Rimnicu Vilcea (next to the Jay Pasachoff's station set up by Williams College) in central Romania. I include one sample image picked out of the 120 exposures made with the small portable CCD camera (attachment : raw image showing the inner and intermediate corona, as well as the now famous prominences). Most stations were run by amateur eclipse chasers and used photography. Several films which were developed in the last few days contain excellent coronal images. They were made by following the basic requirements and observing procedure required for the TECONet project : all on the same calibrated films (Tmax 400 rolls with pre-exposures in the laboratory), stepped exposures and image sequences taken trough a rotating polarisation filter.
Right now, I am still collecting the films. These films are developed immediately
as they arrive. In a few weeks, all films will be scanned, with a 12-bit intensity
resolution. It is only then that the analysis itself will begin :
- for each individual data set :
- cosmetic corrections (vignetting, etc), co-registration, absolute calibration
- extraction of Stokes parameters of linear polarisation
- compositing of the different exposures to create a single full map
- all data sets together :
- intensity cross-calibration
- rescaling to a common spatial scale and orientation
- intercomparison (search for changes and motions in the corona over 2 hours).
This work will certainly require several months. The result might well be the first multi-station eclipse data set based on an homogeneous set of instruments. Indeed, the diversity of eclipse experiments has always been a major hurdle when trying to compare quantitatively eclipse data from different locations at the same eclipse or from different eclipses.
At this stage, I thus feel pretty happy with the results. In the last few months, I had to pass some moments of doubts, considering the amount of administrative work invested in this project, at the expense of true science. However, on August 11, when the ROB station that I was leading in Alsace (France) was clouded out, instead of being depressed, I realized how useful TECONet would be, as plenty of good data would soon be available. Paperwork was the price to pay, but I did not loose my time.
By the way, I indeed witnessed totality under the rain. The sky was overcast, and clouds were thick enough to allow us to watch the partial phases without protecting filters (attenuation larger than 10000). Still, to our big surprise, we could see the corona through the clouds. It was attenuated and the light was strongly diffused, but we could see it to about 1.5 solar radii. This came as an unhoped-for consolation and the unique excitement of totality was there, despite the terrible weather (worst day of the whole week in Alsace !).
This eclipse was certainly and will probably remain an unique episode in my life. There will be no more total eclipse in Belgium or even central Europe until 2081. I will thus go to future solar eclipses in full anonymity (just like before), without the huge demand from the public and the media. The last year was quite an experience! I learned a lot about the social impact of a total eclipse and of astronomy in general, actually as much as about purely astrophysical aspects of the phenomenon.
F. Clette
TECONet Coordinator
24/8/1999
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Processed films :
J. Ballevre : Vouzier, France
clear sky, perfect sequence,
calibration : good fragments, vignetting : OK
film developed, info : missing totality timing
R. Bareford : Annelles, France
cloudy, strong transparency degradation, tracking problem, probably unusable
calibration : cloudy, vignetting : unreliable
film developed, info : OK
M. Gigolashvili : Elazig, Turkey
clear sky, some good images, tracking problem, non-standard procedure,
calibration : a few exposures, vignetting : OK
film developed, info : OK
V. Kinet : Alsace, France
cloudy, strong transparency degradation, probably unusable
calibration : no, unreliable, vignetting : no
film developed, info : missing totality timing, site ?
A. Lindquist : Albena, Bulgaria
clear sky, good sequence, coronal decentred
calibration : OK, vignetting : OK
film developed, info : OK
I. Ross : Csopak, Balaton, Hungary
thin high clouds, severe smearing due to vibrations, probably unusable
calibration : post-totality, vignetting : no
film developed, info : OK
D. Trowbridge : Pacs, Hungary
apparently clear, some good sequences, tracking lost for last 2 frames
calibration : OK, vignetting : OK
film developed (2), info : missing totality timing
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Films to be developed :
J. Draeger : Hungary
manipulation errors ?
film to be shipped, info : not yet documented
A. Ozguc : Elazig, Turkey
clear sky
calibration : OK, vignetting : OK
film received, info : totality timing to be checked
J. Sykora, P. Bendik : Fulopjakab, Kecskemet, Hungary
clear sky
calibration : OK, vignetting : OK
film received, info : OK
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Good news :
EAGB-Romania (ROB): Ramnicu-Valcea, Romania, CCD+photo, success, 120 CCD images
T. Mirtorabi : Tiran, Iran
clear sky,
film to be shipped, info : not yet documented
J. Pasachoff : Ramnicu-Valcea, Romania
clear sky, sucessful observations (CCD)
G. Szecsenyi-Nagy : Tihany & Zamardi, Hungary
clear sky
film to be shipped, info : not yet documented
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The "black list" :
P. Corelli : Salzburg, Austria, no observations (clouded out)
A. Desai : Isfahan, Iran, no observations (equipment failure during totality)
EAGB-France (ROB): Niederbronn, Alsace, France, CCD + photo, no observations
(clouded out)
GFOES-A. Philippe : Oberroedern, Alsace, France, no observations (clouded out)
GFOES-P. Gredin : Oeuilly, Aisne, France, no observations (clouded out)
F. Heinicke : Stuttgart, Germany, no observations (clouded out)
L. Korosi : Timisoara, Romania, no observations (clouded out)
F. Rouviere : Alsace, France, no observations (clouded out)
D. Sarkar : Virandiyara Village, India, no observations (clouded out)
D. Staps : Munich, Germany, no observations (clouded out)
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No news yet from :
C. Cox, Reims, France
G. Nickas, Sivas, Turkey
I. Rodriguez-Hidalgo (IACanarias), Kastamonu, Turkey
S. Rosoni, Stuttgart, Germany
L. Van Driel (OPMeudon), Szombathely, Hungary