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Last week I mentioned an impressive NLC display that we observed at 51 deg
N
in Chemnitz/Germany on July, 30. During our observation I made four photo-
graphic series of the event with 5 min distance between two exposures.
I used a 2,8/29 mm wide angle and a normal 2,8/50 mm photo lens with
exposure times of 30 s and 60 s on a AGFA XRG-200 and Polaroid DX-200
colour film.
I just got the print from the photo shop. They show really impressive the
fast development on the clouds, which was also mentioned in the June
report of Juergen Rendtel. Using the wide angle lens you have the chance
to catch the complete display but most of the fine structure gets lost.
The standard lens (2,8/50) catches only parts of the display but you
also get more detailed pictures. Finally you really need a tele lens (I
checked a 2,8/135 mm lens) to obtain all the fine details of NLC.
Unfortunately you will never get the whole display this way.
The exposure time is not so important: Both the 30 s and the 60 s
exposures
show virtually no differences. Thus I will use 1 min exposures in the
future
because the colour of the sky looks better.
This afternoon I digitized some of the images and put them to my web page.
If you want to see how fast the clouds developed and how easy they were
visible even in a big city like Chemnitz (>200.000 inhabitants) just have
a look at http://www.tu-chemnitz.de/~smo/nlc/serie.html.
Regards, Sirko Molau
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