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Re: [APML] Stacking Software



Roland;
    I don't have the latest version of RegiStar loaded, so perhaps someone else can comment on whether or not there are more methods of stacking beyond average and overlay. I believe median combine is available. Where RegiStar really shines is in areas that you don't have problems with CCD. Film can distort or change dimensions slightly with humidity, or can buckle slightly. My understanding of Maxim suggests that when an image is rescaled or rotated, it is applied equally to the entire image. If one image has non-linear distortion due to humidity, the stars could never line up across the entire image. With PW this can be done, but requires many registration points to set up and a lot of checking in "difference" mode. Registar aligns on EVERY star in the image.
    As Bobby pointed out, alignment of mosaics against a widefield image to reduce edge distortion is easy in RegiStar. I don't know if Maxim will align just the outer edges of an image. Registar is often used to clean up lateral chromatic problems with cheap refractors. Within Registar you can break an image into RGB, align the colours and recombine. This really helps clean up blue halos which are displaced more around the edges of an image than they are in the center. Not that you would have to worry about this.... <g>
 
John Mirtle
Calgary, Ab. Canada
----- Original Message -----
Sent: Thursday, September 26, 2002 12:20 PM
Subject: Re: [APML] Stacking Software

In a message dated 9/25/2002 2:44:46 PM Central Daylight Time, jml@astropix.com writes:


>I'm looking for a better stacking software program I can use with my
>negatives and digital images. I've been using Picture Window, but manual
>alignment of more than 1 or 2 shots gets very tedious. Any one have a
>suggestion?
>Astrostack isn't bad but its very limited.


I use Maxim DL which has several different methods of alignment, both manual and automatic. It will align images at 16 bit, avarage them or sum them. the sum fuction is useful when combining images with different levels of exposure. Does Registar have any additional features that would be more useful than Maxim?

Roland Christen