[ATMoB-discuss] First photo from C14/ST7

[Buonomo, John]

 Hi Bruce
I jumping in here late..
Mario has hit most of the major topics 

About the blur, I would say if you have limited images to stack... a
slight blur would work, but more time on a target is always best.
As for Darks, yes they are to remove the hot pixels as well as other
noise 
A bias frames are for the electronic chip noise. 
I use a software tool that creates a hot pixel map this is better then
darks because is can be scaled and created ahead of time...I have
learned that taking many dark frames and stacking them into a master
dark will get rid of most of the hot pixels, Flats are good to remove
the optical artifacts like dust motes and vignetting.

This m57 just needs more images stacked but it is a EXCELLENT start for
the C14 

Not sure if this will help but my average processing steps for a given
evening and optical config
As sky is darkening I take as many sky flats as possible 
Stack these for a master sky flat and apply a matching hot pixel map to
this master flat.
Take my evening's images (as night progresses my camera's amp glow and
hot pixels increase)
At sign of clouds or twilight I cover the scope's objective and take as
many dark frames as I can before the sun rises, or begins to rain...:)

Later I stack the darks and create a master dark and I use a master bias
that I created during a rainy day...(many chances there:)

I will  then apply the master flat dark and bias to each raw image and
then stack the raw for a summed master for processing

Depending on the target it is either Stretching or DDP for brining out
the detail and other various tricks I picked up from reading the e-book
Photoshop for astrophotography 

As for the image did you use a auto guider at all? And what was each
exposures set at?

Thanks
John


John Buonomo
http://www.astronight.com/




-----Original Message-----
From: atmob-discuss-bounces at atmob.org
[mailto:atmob-discuss-bounces at atmob.org] On Behalf Of Bruce Berger
Sent: Tue., Aug. 08, 2006 2:17 PM
To: atmob-discuss at atmob.org
Subject: RE: [ATMoB-discuss] First photo from C14/ST7

I may be misunderstanding something. I thought the dark exposures were
supposed to null out the hot & dark pixels. How do you subtract them
separately? Should I apply a 2-4 pixel Gaussian blur?

Bruce

-----Original Message-----
From: mmotta at massmed.org [mailto:mmotta at massmed.org] 
Sent: Tuesday, August 08, 2006 1:53 PM
To: bruce at scopemaker.com
Subject: RE: [ATMoB-discuss] First photo from C14/ST7

Choose only those that have tracked well.
do basic processing on each (Dark/ flatt field/ bias).
Then, do the hot and dark pixels on each.
Then, stack your best ones, and do all higher level processing (digital
processing, masking, etc ) on the combined deeper stacked image.

Mario

On Tue, 8 Aug 2006 13:44:17 -0400, "Bruce Berger" wrote:

> 
> Thank you. So here's a question - I have about 8
images
> @ 3 or 5 minute
> exposures. Should I align and stack, and THEN apply Dark & Bias 
> frames, or should the Dark & Bias be applied to each frame before 
> stacking?
> 
> I do not have MaxIm, but I do have Registax, CCDSoft 5.0 and Photoshop

> CS2.
> 
> Bruce
> 
> -----Original Message-----
> From: mmotta at massmed.org [mailto:mmotta at massmed.org]
> Sent: Tuesday, August 08, 2006 1:35 PM
> To: valleli at rcn.com
> Cc: bruce at scopemaker.com; atmob-discuss at atmob.org
> Subject: Re: [ATMoB-discuss] First photo from C14/ST7
> 
> Look on the black "sky" and you will see single pixel white dots. 
> Those are hot pixels.
> Mario
> 
> On Tue,  8 Aug 2006 13:19:35 -0400 (EDT), valleli at rcn.com wrote:
> 
> > 
> > Mario,
> > 
> > I see the dark pixels, no problem. Not sure what you
> are referring to
> > for 'hot' pixels.
> > 
> > Is it the mottled (grainy) background?
> > 
> > I downloaded the JPG and then viewed it in
Photoshop.
> > 
> > What I saw on the laptop screen had a lot more
detail
> in the ring than
> > this processed exposure shows.
> > 
> > Would binning for such a small object have been
> helpful?
> > 
> > Paul
> 
> 
> _______________________________________________
> ATMoB-discuss mailing list
> ATMoB-discuss at atmob.org
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