1818RE: [ccd-newastro] Re: Can someone let me use their M101 B channel?
- Apr 1, 2001This won't work well unless the L image was done with IR blocking.
Otherwise, you have IR + R + B + G in the original image, and performing
just L - R - G will leave you with B + IR.
I've sent instructions for how to do this in Maxim separately. Be sure to do
darks and flats before you perform the math.
The New CCD Astronomy
From: jeffh@... [mailto:jeffh@...]
Sent: Saturday, March 31, 2001 7:15 PM
Subject: [ccd-newastro] Re: Can someone let me use their M101 B channel?
Yeah, I already thought of that--but I wasn't sure of how to do it
with the software I have available. Actually, I thought someone like
you would see this and tell me how <g>. I've got MaxImDL and PS
Anyone know how to do this subtraction?
--- In ccd-newastro@y..., "Eddie Trimarchi" <eddiet@b...> wrote:
> You could try synthesising a B image from what you have.
> Theoretically L = R + G + B
> so B = L - R - G
> The trick is matching the levels first so that the B data is
> It can be done though.
> Eddie Trimarchi
> >-----Original Message-----
> >From: jeffh@n... [mailto:jeffh@n...]
> >Sent: Sunday, April 01, 2001 9:43 AM
> >To: ccd-newastro@y...
> >Subject: [ccd-newastro] Can someone let me use their M101 B
> >It's snowing again here in WI, and I'm Jonesin' for some
> >A few weeks back I got 1 hour of L, and 30 minutes each of R and G
> >M101 at full resolution on my ST8E. I'd like to be able to stitch
> >together the whole image, but my blue image was lost when my mount
> >broke and stopped tracking (Ron W, if you're reading this you may
> >pleased to know that I traded up to an NJP).
> >Anyway, I would prefer a full-resolution image from an ST8E,
> >somewhere in the 30-45 minute range, but I'll take whatever. I
> >using a 5" refractor at f/8 if that gives any else any idea of
> >but again, that's less relevant.
> >I'd just like to get some practice with my LRGB processing of
> >galaxies, and besides an M51 shot that I have whipped like a dead
> >horse, this is the only other I have.
> >Anybody willing to help? I have broadband, so you can send me
> >files...you'll save me from the "snowy, cloudy skies blues."
> >Feel free to email them to me.
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