PixInsight Forum (historical)

PixInsight => General => Off-topic => Topic started by: h0ughy on 2010 February 15 18:57:51

Title: star alignment process with different sized images?
Post by: h0ughy on 2010 February 15 18:57:51
Can the star alignment process be used to align say a widefield image (lets say taken with a canon 20D and a 200mm lens) and a narrower image (lets say a 8" f4 scope image? but with same camera) so as to provide finer detail to the final image.   like say an orion widefield shot normally overexposing the core of M42, and adding in a processed closeup image of m42?
Title: Re: star alignment process with different sized images?
Post by: dhalliday on 2010 February 15 20:07:42
Hmmmnnn...(!!!)
I think SA will ALIGN just about ANYTHING...including two photos of you,taken 40 years apart...,as long as your eyes and two teeth remain >:D
BUT...to COMBINE them,somehow....the wide field is going to be contributing about 4 pixels to the image.
I would combine two disparate images with DYNAMIC alignment,for starters...
But with vastly different scale,I think the point of combining is lost,no?
Try and flesh out for me how you feel that sticking these two images together will help you...(!!)
Dave
Title: Re: star alignment process with different sized images?
Post by: h0ughy on 2010 February 15 21:40:54
Hmmmnnn...(!!!)
I think SA will ALIGN just about ANYTHING...including two photos of you,taken 40 years apart...,as long as your eyes and two teeth remain >:D
BUT...to COMBINE them,somehow....the wide field is going to be contributing about 4 pixels to the image.
I would combine two disparate images with DYNAMIC alignment,for starters...
But with vastly different scale,I think the point of combining is lost,no?
Try and flesh out for me how you feel that sticking these two images together will help you...(!!)
Dave

well i watched the video Juan did and that filled me with hope - -will try it sometime soon and get a result - LOL good or bad
Title: Re: star alignment process with different sized images?
Post by: Jack Harvey on 2010 February 16 06:05:50
Not exactly what you asked but a bit related?  http://www.pixinsight.com/nsaunders/Combining_Different_Exposures.wmv
Title: Re: star alignment process with different sized images?
Post by: h0ughy on 2010 February 16 11:36:47
Not exactly what you asked but a bit related?  http://www.pixinsight.com/nsaunders/Combining_Different_Exposures.wmv
Jack I get a HTTP 404 error on the link
Title: Re: star alignment process with different sized images?
Post by: Jack Harvey on 2010 February 16 11:37:50
Hmmm Niall posted the video so maybe he took it down?
Title: Re: star alignment process with different sized images?
Post by: Juan Conejero on 2010 February 16 14:59:33
Sorry, this video is still on the old server. You can download it here:

http://74.50.19.20/nsaunders/Combining_Different_Exposures.wmv

I'll try to move all pending files to the new server ASAP. Sorry for the inconvenience!
Title: Re: star alignment process with different sized images?
Post by: Juan Conejero on 2010 February 16 15:04:36
Quote
Can the star alignment process be used to align say a widefield image (lets say taken with a canon 20D and a 200mm lens) and a narrower image (lets say a 8" f4 scope image? but with same camera) so as to provide finer detail to the final image.

Probably not with the default SA parameters. If the scale difference is large and the images are dissimilar in their contents, you'll have to tweak star detection parameters.

Although it can register images under these conditions, StarAlignment has not been designed specifically to carry out these tasks. In this case, the DynamicAlignment process is probably your best option in PixInsight.
Title: Re: star alignment process with different sized images?
Post by: h0ughy on 2010 February 16 17:05:53
Quote
Can the star alignment process be used to align say a widefield image (lets say taken with a canon 20D and a 200mm lens) and a narrower image (lets say a 8" f4 scope image? but with same camera) so as to provide finer detail to the final image.

Probably not with the default SA parameters. If the scale difference is large and the images are dissimilar in their contents, you'll have to tweak star detection parameters.

Although it can register images under these conditions, StarAlignment has not been designed specifically to carry out these tasks. In this case, the DynamicAlignment process is probably your best option in PixInsight.

so how does that work?
Title: Re: star alignment process with different sized images?
Post by: Niall Saunders on 2010 February 16 23:44:25
Quote
so how does that work?

I have a video almost completed, not quite ready for upload, which deals with Dynamic Alignment.

I just need some more spare time - maybe by this weekend . . .


Cheers,
Title: Re: star alignment process with different sized images?
Post by: h0ughy on 2010 February 17 02:32:16
Quote
so how does that work?

I have a video almost completed, not quite ready for upload, which deals with Dynamic Alignment.

I just need some more spare time - maybe by this weekend . . .


Cheers,
oh fantastic Mr Saunders- i will be looking forward to this. Between you and Harry and  Juan the videos are brilliant, thanks for your help.
Title: Re: star alignment process with different sized images?
Post by: Harry page on 2010 February 17 02:43:15
Hi


If you look at this video http://www.harrysastroshed.com/lrgb.HTML (http://www.harrysastroshed.com/lrgb.HTML)

It does show how to use it  ;D

The reason I used it in this video was there was a scale difference between my rgb and lum  ;)


Harry

I will forgive you for not watching it earlier