Re: [APML]Emission Lines Question and missing Veil

["John C. Mirtle" <jmirtle@shaw.ca>]

William;
    I would have to concur with Gerry. In my cold camera days (now I'm
dating myself!) I went after the veil many times. Ektachrome 400 chilled was
almost blind to it, picking up only a hint of it in red. Other nebula came
pounding through, but not the veil. Chilled Gold 400 did much better, but
Royal Gold (400-2)  was simply magic. Chilled with a deep sky filter, it
picked up all sorts of reds, oranges, yellows and green.
http://members.shaw.ca/jmirtle/wveil.htm Granted, the colour balance was
technically wrong, but at least the film responded in some way to OIII. My
guess is that the Veil's OIII fell in your film's blue/green crossover
notch, and Kodak truncated red response before Ha. The point is that we film
based guys are totally at the mercy of film manufacturers when it comes to
the success or failure of our images. (assuming that we do our part right!)
Right now, it seems that they are kicking the tar out of us - at least on
print film. The difference between my sucess and failure was not technique,
it was just different film. At least CCD cameras will give consistant
results for the life of the camera. But then, dry ice is way more fun at
star parties!
    30 minutes with a Schmidt should have turned the film into a solar
filter! Might I suggest a switch to slide film? 7 minutes on E200 will get
you tons of veil, from a really dark site. Push processing NOT required. You
will only pick up red, not the subtle hues that Chuck Vaugn recorded in
tri-colour. At least you will get something! With 7 minute shots, you can
even spend all the extra time to get extra images for stacking. If you
really want to get the veil, try a Wratten 92 and hypered tech pan.... :-)

John (dry ice)  Mirtle
Calgary, Ab. Canada



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