From: "Tim" <tjp314@pacbell.net>

Date: April 17, 2008 11:57:35 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: Stacking Images

If you combine your stacks in something like Photoshop, you can cut

out the "bad" areas in each layer using a feathered selection tool

(like the lasso) after registering the stacks, feathering the edge of

the cut by several pixels. I do this all the time still with Mars

Orbiter image mosaics - it's a great way to trim off edges of frames.

-Tim.

--- In Astro_IIDC@yahoogroups.com, Milton Aupperle <milton@...> wrote:

Dean;

It depends.

If I have mediocre seeing, sometimes I pick multiple areas because I

can't predict whether I will get good matches or not. So I pick

several areas in case the "boiling" turbulence causes fewer frames to

be selected at say "High" matching tolerances than I want. Then I use

the text log file to see how many frames were actually use din the

stack and pick which one fits my needs best.

People like Alan Friedman do fine aligns on specific areas of the

image and then cut and paste the portions around them to make a

merged mosaic. I rarely have skies that good to bother with that sort

of thing.

I know that some app will try to re-assemble the selection areas into

a unified image, but my and other's experience with it is that it

only works under extremely good seeing. Otherwise you wind up with

mismatched areas and very obvious joins under average seeing conditions.

Hope That Helps..

Milton J. Aupperle

President

ASC - Aupperle Services and Contracting

Mac Software (Drivers, Components and Application) Specialist

#1005 - 815 14th Avenue. S.W.

Calgary Alberta T2R0N5

1-(403)-229-9456

milton@...

www.outcastsoft.com

On 17-Apr-08, at 11:20 AM, dean_drumheller wrote:

Is there an advantage to choosing more than one alignment point?

Thanks, Dean--- In Astro_IIDC@yahoogroups.com, Milton Aupperle

<milton@> wrote:

Dear Dean;

On 17-Apr-08, at 9:12 AM, dean_drumheller wrote:

After running an align & stack procedure, the result is 4 images

instead of one. I'm choosing

four alignment points manually. What are the 4 images the

result

of? How do I change

settings to combine these four images ?

There is no combination of the resulting stacks. Astro IIDC creates

stacked image for each alignment area you selected.