Re: [APML]: Constellation photography

[Axel Mellinger <axm2@canopus.physik.uni-potsdam.de>]

The Astro-Photography Mailing List
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> >We have all (I hope !) seen wide field photo's by Akira Fuji (amongst
> >others).  Does anyone know about the technique to record such a rich
> >star-colours in these kind of photographs ?
> 
> 
> He uses a diffusion filter over the lens during at least part of the
> exposure. Diffusion filters (sometimes called "soft focus" filters) come in
> many varieties, varying not only in the amount of diffusion but in the type
> of diffusion introduced. Different types of diffusion filters produce
> different effects, so you'll need to experiment to find what effect you
> like.

I inadvertently achieved a similar effect on a trip to South Africa
earlier this year. Humidity was extremely high after a thunderstorm had
hit us the day before. Even though I kept my camera lenses in a warm
pocket of my jacket until the last minute before I started shooting, some
dew built up on the front lens during the 30 min exposure, producing big
halos around bright stars while leaving the fainter stars mostly 
unchanged. 

Two examples can be found on my web site:

http://canopus.physik.uni-potsdam.de/~axm/photo.cgi?Image=images/1998-01_06
http://canopus.physik.uni-potsdam.de/~axm/photo.cgi?Image=images/1998-02_03

So, if you live in a humid climate, you could try to fog your camera lens 
with your breath. Not very reproducible, though ;-)

Clear skies,

Axel



-- 
Axel Mellinger  <http://canopus.physik.uni-potsdam.de/~axm/astrophot.html>