RE: [APML] Iris nebula; processing help needed

[John Mirtle <spampit@shaw.ca>]

Alan,
	Nice work! The outer regions of this nebula are just not that
bright. To improve your signal to noise you can either slap on a compressor
to increase brightness at the focal plane, (I assume you are shooting at
f8?) or switch to a film with better reciprocity characteristics. Hypered
film like tech pan will work nicely for you here. The bright parts have
recorded nicely, but the faint parts illustrate nicely an earlier post about
faint light suffering from more recip. failure than the bright parts. Your
results look a lot like the Supra 400 I had. After 1 roll I stopped using
it. Since you are exposing for so long, why not try a few shots on
Ektachrome E200? I think that you will get more density than with the Supra.
Supra in my experience just doesn't like working in the f8-f10 range. E200
does!

	A film image of ngc7023? You bet! Got one at
http://www.astrofoto.ca/john/n7023.htm and it's even manually guided. :)

John Mirtle
Calgary, Ab. Canada

-----Original Message-----
From: astro-photo-bounces@seds.org [mailto:astro-photo-bounces@seds.org] On
Behalf Of Alan Voetsch
Sent: Thursday, September 23, 2004 1:00 PM
To: APML
Subject: [APML] Iris nebula; processing help needed

All,

I have been trying to improve this image. I took the one posted a couple
days ago, combined it with another negative I just got back, zoomed in and
cropped a bit. My current progress is here:
http://www.pbase.com/avoetsch12952/image/34162671

I've played with RGB curves a bit, applied some sort of USM, and a Gaussian
blur. I like to hear any ideas to bring out more detail, if that's possible.
Maybe there just is not enough signal to begin with.
One image is a 185 minute exposure and the original is 120 minutes. If more
signal is needed I'll need quite a few more exposures, because I can't go
much longer than 3 hours. And I'm willing to get more shots if that's what
it'll take.

I don't recall any film images of this object, does anyone have one they can
share with me for inspiration?

As always, thanks,
Alan




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